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diff --git a/34114-8.txt b/34114-8.txt new file mode 100644 index 0000000..a6148ad --- /dev/null +++ b/34114-8.txt @@ -0,0 +1,9326 @@ +The Project Gutenberg EBook of Soap-Making Manual, by E. G. Thomssen + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: Soap-Making Manual + A Practical Handbook on the Raw Materials, Their + Manipulation, Analysis and Control in the Modern Soap Plant. + +Author: E. G. Thomssen + +Release Date: October 22, 2010 [EBook #34114] + +Language: English + +Character set encoding: ISO-8859-1 + +*** START OF THIS PROJECT GUTENBERG EBOOK SOAP-MAKING MANUAL *** + + + + +Produced by David Clarke, Josephine Paolucci and the Online +Distributed Proofreading Team at https://www.pgdp.net. (This +file was produced from images generously made available +by The Internet Archive/American Libraries.) + + + + + + + +Soap-Making Manual + +A practical handbook on the raw materials, their manipulation, analysis +and control in the modern soap plant. + +By + +_E. G. Thomssen, Ph. D._ + +ILLUSTRATED + + +NEW YORK + +D. VAN NOSTRAND COMPANY + +EIGHT WARREN STREET + +1922 + +COPYRIGHT 1922 + +BY + +D. VAN NOSTRAND COMPANY + +Printed in the United States of America + + * * * * * + +Transcriber's note: + +This is a series of articles collected into a book. There are +differences in spelling and punctuation in the different chapters (e.g. +cocoanut in one chapter and coconut in another). These differences were +left in the text as they appeared. + +For Text: A word surrounded by a tilde such as ~this~ signifies that +the word is bolded in the text. A word surrounded by underscores like +_this_ signifies the word is italics in the text. + +For numbers and equations: Parentheses have been added to clarify +fractions. Underscores before bracketed numbers in equations denote a +subscript. + +Minor typos have been corrected and footnotes moved to the end of the +chapters. + + * * * * * + + +PREFATORY NOTE. + + +The material contained in this work appeared several years ago in serial +form in the American Perfumer and Essential Oil Review. Owing to the +numerous requests received, it has been decided to now place before +those interested, these articles in book form. While it is true that the +works pertaining to the soapmaking industry are reasonably plentiful, +books are quite rare, however, which, in a brief volume, will clearly +outline the processes employed together with the necessary methods of +analyses from a purely practical standpoint. In the work presented the +author has attempted to briefly, clearly, and fully explain the +manufacture of soap in such language that it might be understood by all +those interested in this industry. In many cases the smaller plants find +it necessary to dispense with the services of a chemist, so that it is +necessary for the soapmaker to make his own tests. The tests outlined, +therefore, are given as simple as possible to meet this condition. The +formulae submitted are authentic, and in many cases are now being used +in soapmaking. + +In taking up the industry for survey it has been thought desirable to +first mention and describe the raw materials used; second, to outline +the processes of manufacture; third, to classify the methods and +illustrate by formulae the composition of various soaps together with +their mode of manufacture; fourth, to enumerate the various methods of +glycerine recovery, including the processes of saponification, and, +fifth, to give the most important analytical methods which are of value +to control the process of manufacture and to determine the purity and +fitness of the raw material entering into it. + +It is not the intention of the author to go into great detail in this +work, nor to outline to any great extent the theoretical side of the +subject, but rather to make the work as brief as possible, keeping the +practical side of the subject before him and not going into concise +descriptions of machinery as is very usual in works on this subject. +Illustrations are merely added to show typical kinds of machinery used. + +The author wishes to take this opportunity of thanking Messrs. L. S. +Levy and E. W. Drew for the reading of proof, and Mr. C. W. Aiken of the +Houchin-Aiken Co., for his aid in making the illustrations a success, as +well as others who have contributed in the compiling of the formulae for +various soaps. He trusts that this work may prove of value to those +engaged in soap manufacture. + +E. G. T. + +January, 1922 + + + + +TABLE OF CONTENTS. + + +CHAPTER I. Page. + +RAW MATERIALS USED IN SOAP MAKING 1-30 + + 1. Soap Defined 1 + + 2. Oils and Fats 1-2 + + 3. Saponification Defined 2-3 + + 4. Fats and Oils Used in Soap Manufacture 3-4 + Fullers' Earth Process for Bleaching Tallow 4-6 + Method for Further Improvement of Color in Tallow 6 + Vegetable Oils 6-9 + Chrome Bleaching of Palm Oil 9-12 + Air Bleaching of Palm Oil 12-16 + + 5. Rancidity of Oils and Fats 16-18 + Prevention of Rancidity 18 + + 6. Chemical Constants of Oils and Fats 18-19 + + 7. Oil Hardening or Hydrogenating 19-21 + + 8. Grease 21-22 + + 9. Rosin (Colophony, Yellow Rosin, Resina) 22-23 + + 10. Rosin Saponification 23-24 + + 11. Naphthenic Acids 24-25 + + 12. Alkalis 25-26 + Caustic Soda 26 + Caustic Potash 26-28 + Sodium Carbonate (Soda Ash) 28-29 + Potassium Carbonate 29 + + 13. Additional Material Used in Soap Making 29-30 + + +CHAPTER II. + +CONSTRUCTION AND EQUIPMENT OF A SOAP PLANT 31-34 + + +CHAPTER III. + +CLASSIFICATION OF SOAP MAKING METHODS 35-46 + + 1. Full Boiled Soaps 36-42 + + 2. Cold Process 43-44 + + 3. Carbonate Saponification 45-46 + + +CHAPTER IV. + +CLASSIFICATION OF SOAPS 47-104 + + 1. Laundry Soap 48 + Semi-Boiled Laundry Soap 49-50 + Settled Rosin Soap 50-54 + + 2. Chip Soap 54-55 + Cold Made Chip Soap 55-56 + Unfilled Chip Soap 56 + + 3. Soap Powders 56-59 + Light Powders 60-61 + + 4. Scouring Powders 61 + + 5. Scouring Soap 61-62 + + 6. Floating Soap 62-65 + + 7. Toilet Soap 65-68 + Cheaper Toilet Soaps 68-69 + Run and Glued-up Soaps 69-71 + Curd Soap 71-72 + Cold Made Toilet Soaps 72-73 + Perfuming and Coloring Toilet Soaps 73-75 + Coloring Soap 75-76 + + 8. Medicinal Soaps 76-77 + Sulphur Soaps 77 + Tar Soap 77 + Soaps Containing Phenols 77-78 + Peroxide Soap 78 + Mercury Soaps 78 + Less Important Medicinal Soaps 78-79 + + 9. Castile Soap 79-81 + + 10. Eschweger Soap 81-82 + + 11. Transparent Soap 82-84 + Cold Made Transparent Soap 84-87 + + 12. Shaving Soaps 87-90 + Shaving Powder 90 + Shaving Cream 90-93 + + 13. Pumice or Sand Soaps 93-94 + + 14. Liquid Soaps 94-95 + + 15. Use of Hardened Oils in Toilet Soaps 96-98 + + 16. Textile Soaps 98 + Scouring and Fulling Soaps for Wool 98-100 + Wool Thrower's Soap 100-101 + Worsted Finishing Soaps 101 + Soaps Used in the Silk Industry 101-103 + Soaps Used for Cotton Goods 103-104 + + 17. Sulphonated Oils 104-105 + + +CHAPTER V. + +GLYCERINE RECOVERY 105-126 + + 1. Methods of Saponification 105-106 + Recovery of Glycerine from Spent Lye 106-113 + Twitchell Process 113-118 + Autoclave Saponification 118 + Lime Saponification 118-120 + Acid Saponification 120-121 + Aqueous Saponification 121 + Splitting Fats with Ferments 121-123 + Krebitz Process 123-125 + + 2. Distillation of Fatty Acids 125-126 + + +CHAPTER VI. + +ANALYTICAL METHODS 127-164 + + 1. Analysis of Oils and Fats 128 + Free Fatty Acids 128-130 + Moisture 130 + Titer 130-132 + Determination of Unsaponifiable Matter 132-133 + Test for Color of Soap 133-134 + Testing of Alkalis Used in Soap Making 134-137 + + 2. Soap Analysis 137-138 + Moisture 138-139 + Free Alkali or Acid 139-142 + Insoluble Matter 143 + Starch and Gelatine 143-144 + Total Fatty and Resin Acids 144 + Determination of Rosin 144-147 + Total Alkali 147-148 + Unsaponifiable Matter 148 + Silica and Silicates 148-149 + Glycerine in Soap 149-150 + Sugar in Soap 150 + + 3. Glycerine Analysis 150-151 + Sampling 151 + Analysis 151-154 + Acetin Process for the Determination of Glycerol 155-156 + The Method 156-159 + Ways of Calculating Actual Glycerol Contents 159-160 + Bichromate Process for Glycerol Determination + Reagents Required 160-161 + The Method 161-162 + Sampling Crude Glycerine 162-164 + + +CHAPTER VII + +STANDARD METHODS FOR THE SAMPLING AND ANALYSIS OF +COMMERCIAL FATS AND OILS 165-195 + + 1. Scope, Applicability and Limitations of the Methods 165-166 + Scope 165 + Applicability 166 + Limitations 166 + Sampling 166-169 + Tank Cars 166-167 + Barrels, Tierces, Casks, Drums, and Other Packages 168 + + 2. Analysis 169-183 + Sample 169 + Moisture and Volatile Matter 170-172 + Insoluble Impurities 172-173 + Soluble Mineral Matter 173 + Free Fatty Acids 174 + Titer 174-175 + Unsaponifiable Matter 176-177 + Iodine Number-Wijs Method 177-181 + Saponification Number (Koettstorfer Number) 181 + Melting Point 181-182 + Cloud Test 182-184 + + 3. Notes of the Above Methods 184-196 + Sampling 183 + Moisture and Volatile Matter 184-187 + Insoluble Impurities 187 + Soluble Mineral Matter 187-188 + Free Fatty Acid 188-189 + Titer 189 + Unsaponified Matter 190-193 + Melting Point 193-196 + +Plant and Machinery 198-219 + Illustrations of Machinery and Layouts of the Plant + of a Modern Soap Making Establishment 198-219 + +Appendix 219-237 + + Useful Tables + +Index 239 + + + + +CHAPTER I + +Raw Materials Used in Soap Making. + + +Soap is ordinarily thought of as the common cleansing agent well known +to everyone. In a general and strictly chemical sense this term is +applied to the salts of the non-volatile fatty acids. These salts are +not only those formed by the alkali metals, sodium and potassium, but +also those formed by the heavy metals and alkaline earths. Thus we have +the insoluble soaps of lime and magnesia formed when we attempt to wash +in "hard water"; again aluminum soaps are used extensively in polishing +materials and to thicken lubricating oils; ammonia or "benzine" soaps +are employed among the dry cleaners. Commonly, however, when we speak of +soap we limit it to the sodium or potassium salt of a higher fatty acid. + +It is very generally known that soap is made by combining a fat or oil +with a water solution of sodium hydroxide (caustic soda lye), or +potassium hydroxide (caustic potash). Sodium soaps are always harder +than potassium soaps, provided the same fat or oil is used in both +cases. + +The detergent properties of soap are due to the fact that it acts as an +alkali regulator, that is, when water comes into contact with soap, it +undergoes what is called hydrolytic dissociation. This means that it is +broken down by water into other substances. Just what these substances +are is subject to controversy, though it is presumed caustic alkali and +the acid alkali salt of the fatty acids are formed. + + +OILS AND FATS. + +There is no sharp distinction between fat and oil. By "oil" the layman +has the impression of a liquid which at warm temperature will flow as a +slippery, lubricating, viscous fluid; by "fat" he understands a greasy, +solid substance unctuous to the touch. It thus becomes necessary to +differentiate the oils and fats used in the manufacture of soap. + +Inasmuch as a soap is the alkali salt of a fatty acid, the oil or fat +from which soap is made must have as a constituent part, these fatty +acids. Hydrocarbon oils or paraffines, included in the term "oil," are +thus useless in the process of soap-making, as far as entering into +chemical combination with the caustic alkalis is concerned. The oils and +fats which form soap are those which are a combination of fatty acids +and glycerine, the glycerine being obtained as a by-product to the +soap-making industry. + + +NATURE OF A FAT OR OIL USED IN SOAP MANUFACTURE. + +Glycerine, being a trihydric alcohol, has three atoms of hydrogen which +are replaceable by three univalent radicals of the higher members of the +fatty acids, _e. g._, + + OH OR + C_{3} H_{5} OH + 3 ROH = C_{3} H_{5} OR + 3 H_{2}O + OH OR + +Glycerine plus 3 Fatty Alcohols equals Fat or Oil plus 3 Water. + +Thus three fatty acid radicals combine with one glycerine to form a true +neutral oil or fat which are called triglycerides. The fatty acids which +most commonly enter into combination of fats and oils are lauric, +myristic, palmitic, stearic and oleic acids and form the neutral oils or +triglycerides derived from these, _e. g._, stearin, palmatin, olein. +Mono and diglycerides are also present in fats. + + +SAPONIFICATION DEFINED. + +When a fat or oil enters into chemical combination with one of the +caustic hydrates in the presence of water, the process is called +"saponification" and the new compounds formed are soap and glycerine, +thus: + + OR OH + C_{3}H_{5} OR + 3 NaOH = C_{3}H_{5} OH + 3 NaOR + OR OH + +Fat or Oil plus 3 Sodium Hydrate equals Glycerine plus 3 Soap. + +It is by this reaction almost all of the soap used today is made. + +There are also other means of saponification, as, the hydrolysis of an +oil or fat by the action of hydrochloric or sulfuric acid, by autoclave +and by ferments or enzymes. By these latter processes the fatty acids +and glycerine are obtained directly, no soap being formed. + + +FATS AND OILS USED IN SOAP MANUFACTURE. + +The various and most important oils and fats used in the manufacture of +soap are, tallow, cocoanut oil, palm oil, olive oil, poppy oil, sesame +oil, soya bean oil, cotton-seed oil, corn oil and the various greases. +Besides these the fatty acids, stearic, red oil (oleic acid) are more or +less extensively used. These oils, fats and fatty acids, while they vary +from time to time and to some extent as to their color, odor and +consistency, can readily be distinguished by various physical and +chemical constants. + +Much can be learned by one, who through continued acquaintance with +these oils has thoroughly familiarized himself with the indications of a +good or bad oil, by taste, smell, feel and appearance. It is, however, +not well for the manufacturer in purchasing to depend entirely upon +these simpler tests. Since he is interested in the yield of glycerine, +the largest possible yield of soap per pound of soap stock and the +general body and appearance of the finished product, the chemical tests +upon which these depend should be made. Those especially important are +the acid value, percentage unsaponifiable matter and titer test. + +A short description of the various oils and fats mentioned is sufficient +for their use in the soap industry. + +_Tallow_ is the name given to the fat extracted from the solid fat or +"suet" of cattle, sheep or horses. The quality varies greatly, depending +upon the seasons of the year, the food and age of the animal and the +method of rendering. It comes to the market under the distinction of +edible and inedible, a further distinction being made in commerce as +beef tallow, mutton tallow or horse tallow. The better quality is white +and bleaches whiter upon exposure to air and light, though it usually +has a yellowish tint, a well defined grain and a clean odor. It consists +chiefly of stearin, palmitin and olein. Tallow is by far the most +extensively used and important fat in the making of soap. + +In the manufacture of soaps for toilet purposes, it is usually necessary +to produce as white a product as possible. In order to do this it often +is necessary to bleach the tallow before saponification. The method +usually employed is the Fuller's Earth process. + + +FULLER'S EARTH PROCESS FOR BLEACHING TALLOW. + +From one to two tons of tallow are melted out into the bleaching tank. +This tank is jacketed, made of iron and provided with a good agitator +designed to stir up sediment or a coil provided with tangential downward +opening perforations and a draw-off cock at the bottom. The coil is the +far simpler arrangement, more cleanly and less likely to cause trouble. +By this arrangement compressed air which is really essential in the +utilization of the press (see later) is utilized for agitation. A dry +steam coil in an ordinary tank may be employed in place of a jacketed +tank, which lessens the cost of installation. + +The tallow in the bleaching tank is heated to 180° F. (82° C.) and ten +pounds of dry salt per ton of fat used added and thoroughly mixed by +agitation. This addition coagulates any albumen and dehydrates the fat. +The whole mass is allowed to settle over night where possible, or for at +least five hours. Any brine which has separated is drawn off from the +bottom and the temperature of the fat is then raised to 160° F. (71° C). + +Five per cent. of the weight of the tallow operated upon, of dry +Fuller's earth is now added and the whole mass agitated from twenty to +thirty minutes. + +The new bleached fat, containing the Fuller's earth is pumped directly +to a previously heated filter press and the issuing clear oil run +directly to the soap kettle. + +One of the difficulties experienced in the process is the heating of the +press to a temperature sufficient to prevent solidification of the fat +without raising the press to too great a temperature. To overcome this +the first plate is heated by wet steam. Air delivered from a blower and +heated by passage through a series of coils raised to a high temperature +by external application of heat (super-heated steam) is then substituted +for the steam. The moisture produced by the condensation of the steam is +vaporized by the hot air and carried on gradually to each succeeding +plate where it again condenses and vaporizes. In this way the small +quantity of water is carried through the entire press, raising its +temperature to 80°-100° C. This temperature is subsequently maintained +by the passage of hot air. By this method of heating the poor +conductivity of hot air is overcome through the intermediary action of a +liquid vapor and the latent heat of steam is utilized to obtain the +initial rise in temperature. To heat a small press economically where +conditions are such that a large output is not required the entire +press may be encased in a small wooden house which can be heated by +steam coils. The cake in the press is heated for some time after the +filtration is complete to assist drainage. After such treatment the cake +should contain approximately 15 per cent. fat and 25 per cent. water. +The cake is now removed from the press and transferred to a small tank +where it is treated with sufficient caustic soda to convert the fat +content into soap. + +Saturated brine is then added to salt out the soap, the Fuller's earth +is allowed to settle to the bottom of the tank and the soap which +solidifies after a short time is skimmed off to be used in a cheap soap +where color is not important. The liquor underneath may also be run off +without disturbing the sediment to be used in graining a similar cheap +soap. The waste Fuller's earth contains about 0.1 to 0.3 per cent. of +fat. + + +METHOD FOR FURTHER IMPROVEMENT OF COLOR. + +A further improvement of the color of the tallow may be obtained by +freeing it from a portion of its free fatty acids, either with or +without previous Fuller's earth bleaching. + +To carry out this process the melted fat is allowed to settle and as +much water as possible taken off. The temperature is then raised to 160° +F. with dry steam and enough saturated solution of soda ash added to +remove 0.5 per cent. of the free fatty acids, while agitating the mass +thoroughly mechanically or by air. The agitation is continued ten +minutes, the whole allowed to settle for two hours and the foots drawn +off. The soap thus formed entangles a large proportion of the impurities +of the fat. + + +VEGETABLE OILS. + +_Cocoanut Oil_, as the name implies, is obtained from the fruit of the +cocoanut palm. This oil is a solid, white fat at ordinary temperature, +having a bland taste and a characteristic odor. It is rarely +adulterated and is very readily saponified. In recent years the price of +this oil has increased materially because cocoanut oil is now being used +extensively for edible purposes, especially in the making of +oleomargarine. Present indications are that shortly very little high +grade oil will be employed for soap manufacture since the demand for +oleomargarine is constantly increasing and since new methods of refining +the oil for this purpose are constantly being devised. + +The oil is found in the market under three different grades: (1) Cochin +cocoanut oil, the choicest oil comes from Cochin (Malabar). This +product, being more carefully cultivated and refined than the other +grades, is whiter, cleaner and contains a smaller percentage of free +acid. (2) Ceylon cocoanut oil, coming chiefly from Ceylon, is usually of +a yellowish tint and more acrid in odor than Cochin oil. (3) Continental +cocoanut oil (Copra, Freudenberg) is obtained from the dried kernels, +the copra, which are shipped to Europe in large quantities, where the +oil is extracted. These dried kernels yield 60 to 70 per cent oil. This +product is generally superior to the Ceylon oil and may be used as a +very satisfactory substitute for Cochin oil, in soap manufacture, +provided it is low in free acid and of good color. The writer has +employed it satisfactorily in the whitest and finest of toilet soaps +without being able to distinguish any disadvantage to the Cochin oil. +Since continental oil is usually cheaper than Cochin oil, it is +advisable to use it, as occasion permits. + +Cocoanut oil is used extensively in toilet soap making, usually in +connection with tallow. When used alone the soap made from this oil +forms a lather, which comes up rapidly but which is fluffy and dries +quickly. A pure tallow soap lathers very much slower but produces a more +lasting lather. Thus the advantage of using cocoanut oil in soap is +seen. It is further used in making a cocoanut oil soap by the cold +process also for "fake" or filled soaps. The fatty acid content readily +starts the saponification which takes place easily with a strong lye +(25°-35° B.). Where large quantities of the oil are saponified care must +be exercised as the soap formed suddenly rises or puffs up and may boil +over. Cocoanut oil soap takes up large quantities of water, cases having +been cited where a 500 per cent. yield has been obtained. This water of +course dries out again upon exposure to the air. The soap is harsh to +the skin, develops rancidity and darkens readily. + +_Palm Kernel Oil_, which is obtained from the kernels of the palm tree +of West Africa, is used in soap making to replace cocoanut oil where the +lower price warrants its use. It resembles cocoanut oil in respect to +saponification and in forming a very similar soap. Kernel oil is white +in color, has a pleasant nutty odor when fresh, but rapidly develops +free acid, which runs to a high percentage. + +_Palm Oil_ is produced from the fruit of the several species of the palm +tree on the western coast of Africa generally, but also in the +Philippines. The fresh oil has a deep orange yellow tint not destroyed +by saponification, a sweetish taste and an odor of orris root or violet +which is also imparted to soap made from it. The methods by which the +natives obtain the oil are crude and depend upon a fermentation, or +putrefaction. Large quantities are said to be wasted because of this +fact. The oil contains impurities in the form of fermentable fibre and +albuminous matter, and consequently develops free fatty acid rapidly. +Samples tested for free acid have been found to have hydrolized +completely and one seldom obtains an oil with low acid content. Because +of this high percentage of free fatty acid, the glycerine yield is +small, though the neutral oil should produce approximately 12 per cent. +glycerine. Some writers claim that glycerine exists in the free state +in palm oil. The writer has washed large quantities of the oil and +analyzed the wash water for glycerine. The results showed that the +amount present did not merit its recovery. Most soap makers do not +attempt to recover the glycerine from this oil, when used alone for soap +manufacture. + +There are several grades of palm oil in commerce, but in toilet soap +making it is advisable to utilize only Lagos palm oil, which is the best +grade. Where it is desired to maintain the color of the soap this oil +produces, a small quantity of the lower or "brass" grade of palm oil may +be used, as the soap made from the better grades of oil gradually +bleaches and loses its orange yellow color. + +Palm oil produces a crumbly soap which cannot readily be milled and is +termed "short." When used with tallow and cocoanut oil, or 20 to 25 per +cent. cocoanut oil, it produces a very satisfactory toilet soap. In the +saponification of palm oil it is not advisable to combine it with tallow +in the kettle, as the two do not readily mix. + +Since the finished soap has conveyed to it the orange color of the oil, +the oil is bleached before saponification. Oxidation readily destroys +the coloring matter, while heat and light assist materially. The methods +generally employed are by the use of oxygen developed by bichromates and +hydrochloric acid and the direct bleaching through the agency of the +oxygen of the air. + + +CHROME BLEACHING OF PALM OIL. + +The chrome process of bleaching palm oil is more rapid and the oxygen +thus derived being more active will bleach oils which air alone cannot. +It depends upon the reaction: + + Na_{2}Cr_{2}O_{7} + 8HCl = Cr_{2}Cl_{6} + 2NaCl + 7O. + +in which the oxygen is the active principle. In practice it is found +necessary to use an excess of acid over that theoretically indicated. + +For the best results an oil should be chosen containing under 2 per +cent. impurities and a low percentage of free fatty acids. Lagos oil is +best adapted to these requirements. The oil is melted by open steam from +a jet introduced through the bung, the melted oil and condensed water +running to the store tank through two sieves (about 1/8 inch mesh) to +remove the fibrous material and gross impurities. The oil thus obtained +contains fine earthy and fibrous material and vegetable albuminous +matter which should be removed, as far as possible, since chemicals are +wasted in their oxidation and they retard the bleaching. This is best +done by boiling the oil for one hour with wet steam and 10 per cent. +solution of common salt (2 per cent. dry salt on weight of oil used) in +a lead-lined or wooden tank. After settling over night the brine and +impurities are removed by running from a cock at the bottom of the vat +and the oil is run out into the bleaching tank through an oil cock, +situated about seven inches from the bottom. + +The bleaching tank is a lead-lined iron tank of the approximate +dimensions of 4 feet deep, 4 feet long and 3-1/2 feet wide, holding +about 1-1/2 tons. The charge is one ton. A leaden outlet pipe is fixed +at the bottom, to which is attached a rubber tube closed by a screw +clip. A plug also is fitted into the lead outlet pipe from above. Seven +inches above the lower outlet is affixed another tap through which the +oil is drawn off. + +The tank is further equipped with a wet steam coil and a coil arranged +to allow thorough air agitation, both coils being of lead. A good +arrangement is to use one coil to deliver either air or steam. These +coils should extend as nearly as possible over the entire bottom of the +tank and have a number of small downward perforations, so as to spread +the agitation throughout the mass. + +The temperature of the oil is reduced by passing in air to 110° F. and +40 pounds of fine common salt per ton added through a sieve. About +one-half of the acid (40 pounds of concentrated commercial hydrochloric +acid) is now poured in and this is followed by the sodium bichromate in +concentrated solution, previously prepared in a small lead vat or +earthen vessel by dissolving 17 pounds of bichromate in 45 pounds +commercial hydrochloric acid. This solution should be added slowly and +should occupy three hours, the whole mass being thoroughly agitated with +air during the addition and for one hour after the last of the bleaching +mixture has been introduced. The whole mixture is now allowed to settle +for one hour and the exhausted chrome liquors are then run off from the +lower pipe to a waste tank. About 40 gallons of water are now run into +the bleached oil and the temperature raised by open steam to 150° to +160° F. The mass is then allowed to settle over night. + +One such wash is sufficient to remove the spent chrome liquor +completely, provided ample time is allowed for settling. A number of +washings given successively with short periods of settling do not remove +the chrome liquors effectually. The success of the operation depends +entirely upon the completeness of settling. + +The wash water is drawn off as before and the clear oil run to storage +tanks or to the soap kettle through the upper oil cock. + +The waste liquors are boiled with wet steam and the oil skimmed from the +surface, after which the liquors are run out through an oil trap. + +By following the above instructions carefully it is possible to bleach +one ton of palm oil with 17 pounds of bichromate of soda and 85 pounds +hydrochloric acid. + +The spent liquors should be a bright green color. Should they be of a +yellow or brownish shade insufficient acid has been allowed and more +must be added to render the whole of the oxygen available. + +If low grade oils are being treated more chrome will be necessary, the +amount being best judged by conducting the operation as usual and after +the addition of the bichromate, removing a sample of the oil, washing +the sample and noting the color of a rapidly cooled sample. + +A little practice will enable the operator to judge the correspondence +between the color to be removed and the amount of bleaching mixture to +be added. + +To obtain success with this process the method of working given must be +adhered to even in the _smallest detail_. This applies to the +temperature at which each operation is carried out particularly. + + +AIR BLEACHING OF PALM OIL. + +The method of conducting this process is identical with the chrome +process to the point where the hydrochloric acid is to be added to the +oil. In this method no acid or chrome is necessary, as the active +bleaching agent is the oxygen of the air. + +The equipment is similar to that of the former process, except that a +wooden tank in which no iron is exposed will suffice to bleach the oil +in. The process depends in rapidity upon the amount of air blown through +the oil and its even distribution. Iron should not be present or exposed +to the oil during bleaching, as it retards the process considerably. + +After the impurities have been removed, as outlined under the chrome +process, the temperature of the oil is raised by open steam to boiling. +The steam is then shut off and air allowed to blow through the oil until +it is completely bleached, the temperature being maintained above 150° +F. by occasionally passing in steam. Usually a ton of oil is readily and +completely bleached after the air has been passed through it for 18 to +20 hours, provided the oil is thoroughly agitated by a sufficient flow +of air. + +If the oil has been allowed to settle over night, it is advisable to run +off the condensed water and impurities by the lower cock before +agitating again the second day. + +When the oil has been bleached to the desired color, which can be +determined by removing a sample and cooling, the mass is allowed to +settle, the water run off to a waste tank from which any oil carried +along may be skimmed off and the supernatant clear oil run to the +storage or soap kettle. + +In bleaching by this process, while the process consumes more time and +is not as efficient in bleaching the lower grade oils, the cost of +bleaching is less and with a good oil success is more probable, as there +is no possibility of any of the chrome liquors being present in the oil. +These give the bleached oil a green tint when the chrome method is +improperly conducted and they are not removed. + +Instead of blowing the air through it, the heater oil may be brought +into contact with the air, either by a paddle wheel arrangement, which, +in constantly turning, brings the oil into contact with the air, or by +pumping the heated oil into an elevated vessel, pierced with numerous +fine holes from which the oil continuously flows back into the vessel +from which the oil is pumped. While in these methods air, light and heat +act simultaneously in the bleaching of the oil, the equipment required +is too cumbersome to be practical. + +Recent investigations[1] in bleaching palm oil by oxygen have shown that +not only the coloring matter but the oil itself was affected. In +bleaching palm oil for 30 hours with air the free fatty acid content +rose and titer decreased considerably. + +_Olive Oil_, which comes from the fruit of the olive trees, varies +greatly in quality, according to the method by which it is obtained and +according to the tree bearing the fruit. Three hundred varieties are +known in Italy alone. Since the larger portion of olive oil is used for +edible purposes, a lower grade, denatured oil, denatured because of the +tariff, is used for soap manufacture in this country. The oil varies in +color from pale green to golden yellow. The percentage of free acid in +this oil varies greatly, though the oil does not turn rancid easily. It +is used mainly in the manufacture of white castile soap. + +Olive oil foots, which is the oil extracted by solvents after the better +oil is expressed, finds its use in soap making mostly in textile soaps +for washing and dyeing silks and in the production of green castile +soaps. + +Other oils, as poppy seed oil, sesame oil, cottonseed oil, rape oil, +peanut (arachis) oil, are used as adulterants for olive oil, also as +substitutes in the manufacture of castile soap, since they are cheaper +than olive oil. + +_Cottonseed Oil_ is largely used in the manufacture of floating and +laundry soaps. It may be used for toilet soaps where a white color is +not desired, as yellow spots appear on a finished soap in which it has +been used after having been in stock a short time. + +_Corn Oil and Soya Bean Oil_ are also used to a slight extent in the +manufacture of toilet soaps, although the oils form a soap of very +little body. Their soaps also spot yellow on aging. + +Corn oil finds its greatest use in the manufacture of soap for washing +automobiles. It is further employed for the manufacture of cheap liquid +soaps. + +_Fatty Acids_ are also used extensively in soap manufacture. While the +soap manufacturer prefers to use a neutral oil or fat, since from these +the by-product glycerine is obtained, circumstances arise where it is +an advantage to use the free fatty acids. Red oil (oleic acid, elaine) +and stearic acid are the two fatty acids most generally bought for soap +making. In plants using the Twitchell process, which consists in +splitting the neutral fats and oils into fatty acids and glycerine by +dilute sulphuric acid and producing their final separation by the use of +so-called aromatic sulphonic acids, these fatty acids consisting of a +mixture of oleic, stearic, palmitic acids, etc., are used directly after +having been purified by distillation, the glycerine being obtained from +evaporating the wash water. + +Oleic acid (red oil) and stearic acid are obtained usually by the +saponification of oils, fats and greases by acid, lime or water under +pressure or Twitchelling. The fatty acids thus are freed from their +combination with glycerine and solidify upon cooling, after which they +are separated from the water and pressed at a higher or lower +temperature. The oleic acid, being liquid at ordinary temperature, +together with some stearic and palmitic acid, is thus pressed out. These +latter acids are usually separated by distillation, combined with the +press cake further purified and sold as stearic acid. + +The red oil, sometimes called saponified red oil, is often semi-solid, +resembling a soft tallow, due to the presence of stearic acid. The +distilled oils are usually clear, varying in color from light to a deep +brown. Stearic acid, which reaches the trade in slab form, varies in +quality from a soft brown, greasy, crumbly solid of unpleasant odor to a +snow white, wax-like, hard, odorless mass. The quality of stearic acid +is best judged by the melting point, since the presence of any oleic +acid lowers this. The melting point of the varieties used in soap +manufacture usually ranges from 128° to 132° F. Red oil is used in the +manufacture of textile soaps, replacing olive oil foots soap for this +purpose, chlorophyll being used to color the soap green. Stearic acid, +being the hard firm fatty acid, may be used in small quantities to give +a better grade of soap body and finish. In adding this substance it +should always be done in the crutcher, as it will not mix in the kettle. +It finds its largest use for soap, however, in the manufacture of +shaving soaps and shaving creams, since it produces the non-drying +creamy lather so greatly desired for this purpose. Both red oil and +stearic acid being fatty acids, readily unite with the alkali +carbonates, carbon dioxide being formed in the reaction and this method +is extensively used in the formation of soap from them. + + +RANCIDITY OF OILS AND FATS. + +Rancidity in neutral oils and fats is one of the problems the soap +manufacturer has to contend with. The mere saying that an oil is rancid +is no indication of its being high in free acid. The two terms rancidity +and acidity are usually allied. Formerly, the acidity of a fat was +looked upon as the direct measure of its rancidity. This idea is still +prevalent in practice and cannot be too often stated as incorrect. Fats +and oils may be _acid_, or _rancid_, or _acid and rancid_. In an acid +fat there has been a hydrolysis of the fat and it has developed a rather +high percentage of free acid. A rancid fat is one in which have been +developed compounds of an odoriferous nature. An acid and rancid fat is +one in which both free acid and organic compounds of the well known +disagreeable odors have been produced. + +It cannot be definitely stated just how this rancidity takes place, any +more than just what are the chemical products causing rancidity. The +only conclusion that one may draw is that the fats are first hydrolyzed +or split up into glycerine and free fatty acids. This is followed by an +oxidation of the products thus formed. + +Moisture, air, light, enzymes (organized ferments) and bacteria are all +given as causes of rancidity. + +It seems very probable that the initial splitting of the fats is caused +by enzymes, which are present in the seeds and fruits of the vegetable +oils and tissue of animal fats, in the presence of moisture. Lewkowitsch +strongly emphasizes this point and he is substantiated in his idea by +other authorities. Others hold that bacteria or micro-organisms are the +cause of this hydrolysis, citing the fact that they have isolated +various micro-organisms from various fats and oils. The acceptance of +the bacterial action would explain the various methods of preservation +of oils and fats by the use of antiseptic preparations. It cannot, +however, be accepted as a certainty that bacteria cause the rancidity of +fats. + +The action of enzymes is a more probable explanation. + +The hydrolysis of fats and oils is accelerated when they are allowed to +remain for some time in the presence of organic non-fats. Thus, palm +oil, lower grades of olive oil, and tallow, which has been in contact +with the animal tissue for a long time, all contain other nitrogenous +matter and exhibit a larger percentage of free fatty acid than the oils +and fats not containing such impurities. + +Granting this initial splitting of the fat into free fatty acids and +glycerine, this is not a sufficient explanation. The products thus +formed must be acted upon by air and light. It is by the action of these +agents that there is a further action upon the products, and from this +oxidation we ascertain by taste and smell (chemical means are still +unable to define rancidity) whether or not a fat is rancid. While some +authorities have presumed to isolate some of these products causing +rancidity, we can only assume the presence of the various possible +compounds produced by the action of air and light which include oxy +fatty acids, lactones, alcohols, esters, aldehydes and other products. + +The soap manufacturer is interested in rancidity to the extent of the +effect upon the finished soap. Rancid fats form darker soaps than fats +in the neutral state, and very often carry with them the disagreeable +odor of a rancid oil. Further, a rancid fat or oil is usually high in +free acid. It is by no means true, however, that rancidity is a measure +for acidity, for as has already been pointed out, an oil may be rancid +and not high in free acid. + +The percentage of free fatty acid is of even greater importance in the +soap industry. The amount of glycerine yield is dependent upon the +percentage of free fatty acid and is one of the criterions of a good fat +or oil for soap stock. + + +PREVENTION OF RANCIDITY. + +Since moisture, air, light and enzymes, produced by the presence of +organic impurities, are necessary for the rancidity of a fat or oil, the +methods of preventing rancidity are given. Complete dryness, complete +purification of fats and oils and storage without access of air or light +are desirable. Simple as these means may seem, they can only be +approximated in practice. The most difficult problem is the removal of +the last trace of moisture. Impurities may be lessened very often by the +use of greater care. In storing it is well to store in closed barrels or +closed iron tanks away from light, as it has been observed that oils and +fats in closed receptacles become rancid less rapidly than those in open +ones, even though this method of storing is only partially attained. +Preservatives are also used, but only in edible products, where their +effectiveness is an open question. + + +CHEMICAL CONSTANTS OF OILS AND FATS. + +Besides the various physical properties of oils and fats, such as +color, specific gravity, melting point, solubility, etc., they may be +distinguished chemically by a number of chemical constants. These are +the iodine number, the acetyl value, saponification number, +Reichert-Meissl number for volatile acids, Hehner number for insoluble +acids. These constants, while they vary somewhat with any particular oil +or fat, are more applicable to the edible products and are criterions +where any adulteration of fat or oil is suspected. The methods of +carrying out the analyses of oils and fats to obtain these constants are +given in the various texts[2] on oils and fats, and inasmuch as they are +not of great importance to the soap industry they are merely mentioned +here. + + +OIL HARDENING OR HYDROGENATING. + +It is very well known that oils and fats vary in consistency and +hardness, depending upon the glycerides forming same. Olein, a +combination of oleic acid and glycerine, as well as oleic acid itself +largely forms the liquid portion of oils and fats. Oleic acid +(C_{18}H_{34}O_{2}) is an unsaturated acid and differs from stearic acid +(C_{18}H_{36}O_{2}), the acid forming the hard firm portion of oils and +fats, by containing two atoms of hydrogen less in the molecule. +Theoretically it should be a simple matter to introduce two atoms of +hydrogen into oleic acid or olein, and by this mere addition convert +liquid oleic acid and olein into solid stearic acid and stearine. + +For years this was attempted and all attempts to apply the well known +methods of reduction (addition of hydrogen) in organic chemistry, such +as treatment with tin and acid, sodium amalgam, etc., were unsuccessful. +In recent years, however, it has been discovered that in the presence of +a catalyzer, nickel in finely divided form or the oxides of nickel are +usually employed, the process of hydrogenating an oil is readily +attained upon a practical basis. + +The introduction of hardened oils has opened a new source of raw +material for the soap manufacturer in that it is now possible to use +oils in soap making which were formerly discarded because of their +undesirable odors. Thus fish or train oils which had up to the time of +oil hydrogenating resisted all attempts of being permanently deodorized, +can now be employed very satisfactorily for soap manufacture. A Japanese +chemist, Tsujimoto[3] has shown that fish oils contain an unsaturated +acid of the composition C_{18}H_{28}O_{2}, for which he proposed the +name clupanodonic acid. By the catalytic hardening of train oils this +acid passes to stearic acid and the problem of deodorizing these oils is +solved.[4] + +At first the introduction of hardened oils for soap manufacture met with +numerous objections, due to the continual failures of obtaining a +satisfactory product by the use of same. Various attempts have now shown +that these oils, particularly hardened train oils, produce +extraordinarily useful materials for soap making. These replace +expensive tallow and other high melting oils. It is of course impossible +to employ hardened oils alone, as a soap so hard would thus be obtained +that it would be difficultly soluble in water and possess very little +lathering quality. By the addition of 20-25% of tallow oil or some other +oil forming a soft soap a very suitable soap for household use may be +obtained. Ribot[5] discusses this matter fully. Hardened oils readily +saponify, may be perfumed without any objections and do not impart any +fishy odor to an article washed with same. Meyerheim[6] states that +through the use of hydrogenated oils the hardness of soap is +extraordinarily raised, so that soap made from hardened cottonseed oil +is twelve times as hard as the soap made from ordinary cottonseed oil. +This soap is also said to no longer spot yellow upon aging, and as a +consequence of its hardness, is able to contain a considerably higher +content of rosin through which lathering power and odor may be improved. +Hardened oils can easily be used for toilet soap bases, provided they +are not added in too great a percentage. + +The use of hardened oils is not yet general, but there is little doubt +that the introduction of this process goes a long way toward solving the +problem of cheaper soap material for the soap making industry. + + +GREASE. + +Grease varies so greatly in composition and consistency that it can +hardly be classed as a distinctive oil or fat. It is obtained from +refuse, bones, hides, etc., and while it contains the same constituents +as tallow, the olein content is considerably greater, which causes it to +be more liquid in composition. Grease differs in color from an off-white +to a dark brown. The better qualities are employed in the manufacture of +laundry and chip soap, while the poorer qualities are only fit for the +cheapest of soaps used in scrubbing floors and such purposes. There is +usually found in grease a considerable amount of gluey matter, lime and +water. The percentage of free fatty acid is generally high. + +The darker grades of grease are bleached before being used. This is done +by adding a small quantity of sodium nitrate to the melted grease and +agitating, then removing the excess saltpeter by decomposing with +sulphuric acid. A better method of refining, however, is by +distillation. The chrome bleach is also applicable. + + +ROSIN (COLOPHONY, YELLOW ROSIN, RESINA). + +Rosin is the residue which remains after the distillation of turpentine +from the various species of pines. The chief source of supply is in the +States of Georgia North and South Carolina. It is a transparent, amber +colored hard pulverizable resin. The better grades are light in color +and known as water white (w. w.) and window glass (w. g.). These are +obtained from a tree which has been tapped for the first year. As the +same trees are tapped from year to year, the product becomes deeper and +darker in color until it becomes almost black. + +The constituents of rosin are chiefly (80-90%) abietic acid or its +anhydride together with pinic and sylvic acids. Its specific gravity is +1.07-1.08, melting point about 152.5 C., and it is soluble in alcohol, +ether, benzine, carbon disulfide, oils, alkalis and acetic acid. The +main use of rosin, outside of the production of varnishes, is in the +production of laundry soaps, although a slight percentage acts as a +binder and fixative for perfumes in toilet soaps and adds to their +detergent properties. Since it is mainly composed of acids, it readily +unites with alkaline carbonates, though the saponification is not quite +complete and the last portion must be completed through the use of +caustic hydrates, unless an excess of 10% carbonate over the theoretical +amount is used. A lye of 20° B. is best adapted to the saponification of +rosin when caustic hydrates are employed for this purpose, since weak +lyes cause frothing. While it is sometimes considered that rosin is an +adulterant for soap, this is hardly justifiable, as it adds to the +cleansing properties of soap. Soaps containing rosin are of the well +known yellowish color common to ordinary laundry soaps. The price of +rosin has so risen in the last few years that it presents a problem of +cost to the soap manufacturer considering the price at which laundry +soaps are sold. + + +ROSIN SAPONIFICATION. + +As has been stated, rosin may be saponified by the use of alkaline +carbonates. On account of the possibility of the soap frothing over, the +kettle in which the operation takes place should be set flush with the +floor, which ought to be constructed of cement. The kettle itself is an +open one with round bottom, equipped with an open steam coil and skimmer +pipe, and the open portion is protected by a semi-circular rail. A +powerful grid, having a 3-inch mesh, covers one-half of the kettle, the +sharp edges protruding upwards. + +The staves from the rosin casks are removed at the edge of the kettle, +the rosin placed on the grid and beaten through with a hammer to break +it up into small pieces. + +To saponify a ton of rosin there are required 200 lbs. soda ash, 1,600 +lbs. water and 100 lbs. salt. Half the water is run into the kettle, +boiled, and then the soda ash and half the salt added. The rosin is now +added through the grid and the mixture thoroughly boiled. As carbon +dioxide is evolved by the reaction the boiling is continued for one hour +to remove any excess of this gas. A portion of the salt is gradually +added to grain the soap well and to keep the mass in such condition as +to favor the evolution of gas. The remainder of the water is added to +close the soap and boiling continued for one or two hours longer. At +this point the kettle must be carefully watched or it will boil over +through the further escape of carbon dioxide being hindered. The mass, +being in a frothy condition, will rapidly settle by controlling the flow +of steam. The remaining salt is then scattered in and the soap allowed +to settle for two hours or longer. The lyes are then drained off the +top. If the rosin soap is required for toilet soaps, it is grained a +second time. The soap is now boiled with the water caused by the +condensation of the steam, which changes it to a half grained soap +suitable for pumping. A soap thus made contains free soda ash 0.15% or +less, free rosin about 15%. The mass is then pumped to the kettle +containing the soap to which it is to be added at the proper stage. The +time consumed in thus saponifying rosin is about five hours. + + +NAPHTHENIC ACIDS. + +The naphtha or crude petroleum of the various provinces in Europe, as +Russia, Galacia, Alsace and Roumania yield a series of bodies of acid +character upon refining which are designated under the general name of +naphthenic acids. These acids are retained in solution in the alkaline +lyes during the distillation of the naphtha in the form of alkaline +naphthenates. Upon adding dilute sulphuric acid to these lyes the +naphthenates are decomposed and the naphthenic acids float to the +surface in an oily layer of characteristic disagreeable odor and varying +from yellow to brown in color[7]. In Russia particularly large +quantities of these acids are employed in the manufacture of soap. + +The soaps formed from naphthenic acids have recently been +investigated[8] and found to resemble the soaps made from cocoanut oil +and palm kernel oil, in that they are difficult to salt out and +dissociate very slightly with water. The latter property makes them +valuable in textile industries when a mild soap is required as a +detergent, e. g., in the silk industry. These soaps also possess a high +solvent power for mineral oils and emulsify very readily. The mean +molecular weight of naphthenic acids themselves is very near that of the +fatty acids contained in cocoanut oil, and like those of cocoanut oil a +portion of the separated acids are volatile with steam. The iodine +number indicates a small content of unsaturated acids. + +That naphthenic acids are a valuable soap material is now recognized, +but except in Russia the soap is not manufactured to any extent at the +present time. + + +ALKALIS. + +The common alkali metals which enter into the formation of soap are +sodium and potassium. The hydroxides of these metals are usually used, +except in the so called carbonate saponification of free fatty acids in +which case sodium and potassium carbonate are used. A water solution of +the caustic alkalis is known as lye, and it is as lyes of various +strengths that they are added to oils and fats to form soap. The density +or weight of a lye is considerably greater than that of water, depending +upon the amount of alkali dissolved, and its weight is usually +determined by a hydrometer. This instrument is graduated by a +standardized scale, and while all hydrometers should read alike in a +liquid of known specific gravity, this is generally not the case, so +that it is advisable to check a new hydrometer for accurate work against +one of known accuracy. In this country the Baumé scale has been adopted, +while in England a different graduation known as the Twaddle scale is +used. The strength of a lye or any solution is determined by the +distance the instrument sinks into the solution, and we speak of the +strength of a solution as so many degrees Baumé or Twaddle which are +read to the point where the meniscus of the lye comes on the graduated +scale. Hydrometers are graduated differently for liquids of different +weights. In the testing of lyes one which is graduated from 0° to 50° B. +is usually employed. + +_Caustic soda_ is received by the consumer in iron drums weighing +approximately 700 lbs. each. The various grades are designated as 60, +70, 74, 76 and 77%. These percentages refer to the percentage of sodium +oxide (Na_{2}O) in 100 parts of pure caustic soda formed by the +combination of 77-1/2 parts of sodium oxide and 22-1/2 parts of water, +77-1/2% being chemically pure caustic soda. There are generally +impurities present in commercial caustic soda. These consist of sodium +carbonate, sodium chloride or common salt and sometimes lime. It is +manufactured by treating sodium carbonate in an iron vessel with calcium +hydroxide or slaked lime, or by electrolysis of common salt. The latter +process has yet been unable to compete with the former in price. +Formerly all the caustic soda used in soap making was imported, and it +was only through the American manufacturer using a similar container to +that used by foreign manufacturers that they were able to introduce +their product. This prejudice has now been entirely overcome and most of +the caustic soda used in this country is manufactured here. + + +CAUSTIC POTASH. + +The output of the salts containing potassium is controlled almost +entirely by Germany. Formerly the chief source of supply of potassium +compounds was from the burned ashes of plants, but about fifty years ago +the inexhaustible salt mines of Stassfurt, Germany, were discovered. +The salt there mined contains, besides the chlorides and sulphates of +sodium, magnesium, calcium and other salts, considerable quantities of +potassium chloride, and the Stassfurt mines at present are practically +the entire source of all potassium compounds, in spite of the fact that +other localities have been sought to produce these compounds on a +commercial basis, especially by the United States government. + +After separating the potassium chloride from the magnesium chloride and +other substances found in Stassfurt salts the methods of manufacture of +caustic potash are identical to those of caustic soda. In this case, +however, domestic electrolytic caustic potash may be purchased cheaper +than the imported product and it gives results equal to those obtained +by the use of the imported article, opinions to the contrary among soap +makers being many. Most of the caustic potash in the United States is +manufactured at Niagara Falls by the Niagara Alkali Co., and the Hooker +Electrochemical Co., chlorine being obtained as a by-product. The latter +concern employs the Townsend Cell, for the manufacture of electrolytic +potash, and are said to have a capacity for making 64 tons of alkali +daily. + +Since the molecular weight of caustic potash (56) is greater than that +of caustic soda (40) more potash is required to saponify a pound of fat. +The resulting potash soap is correspondingly heavier than a soda soap. +When salt is added to a potassium soap double decomposition occurs, the +potassium soap being transformed to a sodium soap and the potassium +uniting with the chlorine to form potassium chloride. This was one of +the earliest methods of making a hard soap, especially in Germany, where +potash was derived from leeching ashes of burned wood and plants. + + +SODIUM CARBONATE (SODA ASH). + +While carbonate of soda is widely distributed in nature the source of +supply is entirely dependent upon the manufactured product. Its uses are +many, but it is especially important to the soap industry in the so +called carbonate saponification of free fatty acids, as a constituent of +soap powders, in the neutralization of glycerine lyes and as a filler +for laundry soaps. + +The old French Le Blanc soda process, which consists in treating common +salt with sulphuric acid and reducing the sodium sulphate (salt cake) +thus formed with carbon in the form of charcoal or coke to sodium +sulphide, which when treated with calcium carbonate yields a mixture of +calcium sulphide and sodium carbonate (black ash) from which the +carbonate is dissolved by water, has been replaced by the more recent +Solvay ammonia soda process. Even though there is a considerable loss of +salt and the by-product calcium chloride produced by this process is +only partially used up as a drying agent, and for refrigerating +purposes, the Le Blanc process cannot compete with the Solvay process, +so that the time is not far distant when the former will be considered a +chemical curiosity. In the Solvay method of manufacture sodium chloride +(common salt) and ammonium bicarbonate are mixed in solution. Double +decomposition occurs with the formation of ammonium chloride and sodium +bicarbonate. The latter salt is comparatively difficultly soluble in +water and crystallizes out, the ammonium chloride remaining in solution. +When the sodium bicarbonate is heated it yields sodium carbonate, carbon +dioxide and water; the carbon dioxide is passed into ammonia which is +set free from the ammonium chloride obtained as above by treatment with +lime (calcium oxide) calcium chloride being the by-product. + +Sal soda or washing soda is obtained by recrystallizing a solution of +soda ash in water. Large crystals of sal soda containing but 37% sodium +carbonate are formed. + + +POTASSIUM CARBONATE. + +Potassium carbonate is not extensively used in the manufacture of soap. +It may be used in the forming of soft soaps by uniting it with free +fatty acids. The methods of manufacture are the same as for sodium +carbonate, although a much larger quantity of potassium carbonate than +carbonate of soda is obtained from burned plant ashes. Purified +potassium carbonate is known as _pearl ash_. + + +ADDITIONAL MATERIAL USED IN SOAP MAKING. + +Water is indispensable to the soap manufacturer. In the soap factory +_hard_ water is often the cause of much trouble. Water, which is the +best solvent known, in passing through the crevices of rocks dissolves +some of the constituents of these, and the water is known as hard. This +hardness is of two kinds, _temporary_ and _permanent_. Temporarily hard +water is formed by water, which contains carbonic acid, dissolving a +portion of calcium carbonate or carbonate of lime. Upon boiling, the +carbonic acid is driven from the water and the carbonate, being +insoluble in carbon dioxide free water, is deposited. This is the cause +of boiler scale, and to check this a small amount of sal ammoniac may be +added to the water, which converts the carbonate into soluble calcium +chloride and volatile ammonium carbonate. Permanent hardness is caused +by calcium sulphate which is soluble in 400 parts of water and cannot be +removed by boiling. + +The presence of these salts in water form insoluble lime soaps which act +as inert bodies as far as their value for the common use of soap is +concerned. Where the percentage of lime in water is large this should be +removed. A method generally used is to add about 5% of 20° B. sodium +silicate to the hard water. This precipitates the lime and the water is +then sufficiently pure to use. + +_Salt_, known as sodium chloride, is used to a large extent in soap +making for "salting out" the soap during saponification, as well as +graining soaps. Soap ordinarily soluble in water is insoluble in a salt +solution, use of which is made by adding salt to the soap which goes +into solution and throws any soap dissolved in the lyes out of solution. +Salt may contain magnesium and calcium chlorides, which of course are +undesirable in large amounts. The products on the market, however, are +satisfactory, thus no detail is necessary. + +_Filling materials_ used are sodium silicate, or water glass, talc, +silex, pumice, starch, borax, tripoli, etc. + +Besides these other materials are used in the refining of the oils and +fats, and glycerine recovery, such as Fuller's earth, bichromates of +soda or potash, sulphate of alumina, sulphuric and hydrochloric acids +and alcohol. + +A lengthy description of these substances is not given, as their modes +of use are detailed elsewhere. + +FOOTNOTES: + +[1] Seifensieder Zeit, 1913, 40, p. 687, 724, 740. + +[2] Official Methods, see Bull. 107, A. O. A. C., U. S. Dept. Agricult. + +[3] Journ. Coll. of Engin. Tokyo Imper. Univ. (1906), p. 1. Abs. Chem. +Revue f. d. Fett-u. Harz, Ind. 16, p. 84; 20, p. 8. + +[4] Meyerheim--Fort. der Chem., Physik. und Physik. Chem. (1913), 8. 6, +p. 293-307. + +[5] Seifs. Ztg. (1913), 40, p. 142. + +[6] Loc. cit. + +[7] Les Matieres Graisses (1914), 7, 69, p. 3367. + +[8] Zeit. f. Angew. Chem. (1914), 27, 1, p. 2-4. + + + + +CHAPTER II + +Construction and Equipment of a Soap Plant. + + +No fixed plan for the construction and equipment of a soap plant can be +given. The specifications for a soap factory to be erected or remodeled +must suit the particular cases. Very often a building which was +constructed for a purpose other than soap manufacture must be adapted +for the production of soap. In either case it is a question of +engineering and architecture, together with the knowledge obtained in +practice and the final decision as to the arrangement is best solved by +a conference with those skilled in each of these branches. + +An ideal soap plant is one in which the process of soap making, from the +melting out of the stock to the packing and shipping of the finished +product, moves downward from floor to floor, since by this method it is +possible to utilize gravitation rather than pumping liquid fats and +fluid soaps. Convenience and economy are obtained by such an +arrangement. + +The various machinery and other equipment for soap manufacture are well +known to those connected with this industry. It varies, of course, +depending upon the kind of soap to be manufactured, and full +descriptions of the necessary machinery are best given in the catalogs +issued by the manufacturers of such equipment, who in this country are +most reliable. + +To know just what equipment is necessary can very easily be described by +a brief outline of the process various soaps undergo to produce the +finished article. After the saponification has taken place in the _soap +kettle_ the molten soap is run directly into the soap _frames_, which +consist of an oblong compartment, holding anywhere from 400 to 1,200 +pounds, with removable steel sides and mounted upon trucks, in which it +solidifies. In most cases it is advisable to first run the soap into a +_crutcher_ or mixer which produces a more homogeneous mass than if this +operation is omitted. Color and perfume may also be added at this point, +although when a better grade of perfume is added it must be remembered +that there is considerable loss due to volatilization of same. When a +_drying machine_ is employed the molten soap is run directly upon the +rollers of this machine, later adding about 1.0% zinc oxide to the soap +from which it passes continuously through the drying chamber and is +emitted in chip form ready for milling. After the soap has been framed, +it is allowed to cool and solidify, which takes several days, and then +the sides of the frame are stripped off. The large solid cake is cut +with wires by hand or by a _slabber_ into slabs of any desired size. +These slabs are further divided into smaller divisions by the _cutting +table_. In non-milled soaps (laundry soaps, floating soaps, etc.), these +are pressed at this stage, usually by automatic presses, after a thin +hard film has been formed over the cake by allowing it to dry slightly. +In making these soaps they are not touched by hand at any time during +the operation, the pressing, wrapping and packing all being done by +machinery. For a milled soap the large slabs are cut into narrow oblong +shapes by means of the cutting table to readily pass into the feeder of +the _chipper_, the chips being spread upon _trays_ and dried in a _dry +house_ until the moisture content is approximately 15%. + +The process of milling is accomplished by passing the dried soap chips +through a _soap mill_, which is a machine consisting of usually three or +four contiguous, smooth, granite rollers operated by a system of gears +and set far enough apart to allow the soap to pass from a hopper to the +first roller, from which it is constantly conveyed to each succeeding +roller as a thin film, and finally scraped from the last roller to fall +into the _milling box_ in thin ribbon form. These mills are often +operated in tandem, which necessitates less handling of soap by the +operator. The object of milling is to give the soap a glossy, smooth +finish and to blend it into a homogeneous mass. The perfume, color, +medication or any other material desired are added to the dried soap +chips prior to milling. Some manufacturers use an _amalgamator_ to +distribute these uniformly through the soap, which eliminates at least +one milling. When a white soap is being put through the mill, it is +advisable to add from 0.5% to 1% of a good, fine quality of zinc oxide +to the soap, if this substance has not been previously added. This +serves to remove the yellowish cast and any translucency occasioned by +plodding. Too great a quantity of this compound added, later exhibits +itself by imparting to the soap a dead white appearance. Inasmuch as the +milling process is one upon which the appearance of a finished cake of +toilet soap largely depends, it should be carefully done. The number of +times a soap should be milled depends upon the character of a soap being +worked. It should of course be the object to mill with as high a +percentage of moisture as possible. Should the soap become too dry it is +advisable to add water directly, rather than wet soap, since water can +more easily be distributed through the mass. As a general statement it +may be said it is better policy to overmill a soap, rather than not mill +it often enough. + +After the soap has been thoroughly milled it is ready for plodding. A +_plodder_ is so constructed as to take the soap ribbons fed into the +hopper by means of a worm screw and continuously force it under great +pressure through a jacketed cylinder through which cold water circulates +in the rear to compensate the heat produced by friction and hot water at +the front, to soften and polish the soap which passes out in solid form +in bars of any shape and size depending upon the form of the _shaping +plate_ through which it is emitted. The bars run upon a _roller board_, +are cut into the required length by a special _cake cutting table_, +allowed to dry slightly and pressed either automatically or by a foot +power _press_ in any suitable soap _die_. The finished cake is then +ready for wrapping and after due time in stock reaches the consumer. + +Besides the various apparatus mentioned above there are many other parts +for the full equipment of a modern soap plant, such as remelters, pumps, +mixers, special tanks, power equipment, etc. As has been stated, +however, practical experience will aid in judging the practicability as +to installation of these. The various methods of powdering soap are, +however, not generally known. Where a coarse powder is to be produced, +such as is used for common washing powders, no great difficulty is +experienced with the well known Blanchard mill. In grinding soap to an +impalpable powder the difficulties increase. The methods adapted in +pulverizing soaps are by means of disintegrators, pebble mills and +chaser mills. The disintegrator grinds by the principle of attrition, +that is, the material is reduced by the particles being caused to beat +against each other at great velocity; a pebble mill crushes the +substance by rubbing it between hard pebbles in a slowly revolving +cylinder; the chaser mill first grinds the material and then floats it +as a very fine powder above a curb of fixed height. The last method is +particularly adapted for the finest of powder (140 mesh and over). + + + + +CHAPTER III + +Classification of Soap-Making Methods. + + +In the saponification of fats and oils to form soap through the agency +of caustic alkalis, as has been stated, the sodium or potassium salts of +the mixed fatty acids are formed. Sodium soaps are usually termed hard +soaps, and potassium soaps soft. There are, however, a great many +varieties of soaps the appearance and properties of which depend upon +their method of manufacture and the oils or fats used therein. + +The various methods adopted in soap making may be thus classified: + +1. Boiling the fats and oils in open kettles by open steam with +indefinite quantities of caustic alkali solutions until the finished +soap is obtained; ordinarily named _full boiled soaps_. These may be +sub-divided into (a) hard soaps with sodium hydrate as a base, in which +the glycerine is recovered from the spent lyes; (b) hard soaps with soda +as a base, in which the glycerine remains in the soap, e. g., marine +cocoanut oil soaps; (c) soft potash soaps, in which the glycerine is +retained by the soap. + +2. Combining the required amount of lye for complete saponification of a +fat therewith, heating slightly with dry heat and then allowing the +saponification to complete itself. This is known as the _cold process_. + +3. Utilizing the fatty acid, instead of the neutral fat, and combining +it directly with caustic alkali or carbonate, which is incorrectly +termed _carbonate saponification_, since it is merely neutralizing the +free fatty acid and thus is not a saponification in the true sense of +the word. No glycerine is directly obtained by this method, as it is +usually previously removed in the clearage of the fat by either the +Twitchell or autoclave saponification method. + +In the methods thus outlined the one most generally employed is the full +boiled process to form a sodium soap. This method of making soap +requires close attention and a knowledge which can only be obtained by +constant practice. The stock, strength of lyes, heat, amount of salt or +brine added, time of settling, etc., are all influencing factors. + +The principles involved in this process are briefly these: + +The fat is partly saponified with weak lyes (usually those obtained from +a previous boiling in the strengthening change are used), and salt is +added to grain the soap. The mass is then allowed to settle into two +layers. The upper layer is partly saponified fat; the lower layer, or +spent lye, is a solution of salt, glycerine, and contains any albuminous +matter or any other impurity contained in the fat. This is known as the +_killing_ or glycerine change. Strong lyes are now added and the fat +entirely saponified, which is termed the _strengthening change_. The +mass is then allowed to settle and the fluid soap run off above the +"nigre." This operation is called the finish or _finishing_ change. + +The method may be more fully illustrated by a concrete example of the +method of manufacture of a tallow base: + + Charge-- + + Tallow 88 per cent. + Cocoanut oil 10 per cent. + Rosin w. w. 2 per cent. + + Amount charge 10 tons + +About five tons of tallow and one ton of cocoanut oil are pumped or run +into the soap kettle and brought to a boil with wet steam until it +briskly comes through the hot fat. The caustic soda (strengthening lyes +from former boilings may be used here) is gradually added by the +distributing pipe, any tendency to thicken being checked by the +introduction of small quantities of brine ("salt pickle"). If the lye is +added too rapidly the soap assumes a granular appearance, indicating +that the addition of same must be discontinued. Water should then be +added and the mass boiled through until it again closes. When the +addition of the proper amount of caustic soda is nearing its completion +the soap gradually thins. The steam is now cut down to about one turn of +the valve, and brine is rapidly added or salt shoveled in. In ten to +fifteen minutes the steam again breaks through and, from the appearance +of the soap, it can be seen whether sufficient brine has been added. A +sample taken out by means of a long wooden paddle should show the soap +in fine grains with the lyes running from it clear. The steam is then +shut off and the soap allowed to settle from one and one-half to two +hours. In all settlings the longer time this operation is permitted to +continue, the better will the subsequent operations proceed. + +The mixture now consists of a partly saponified layer of fat above the +spent lyes. The lyes are drawn off until soap makes its appearance at +the exit pipe. The valve is then closed and the soap blown back into the +kettle by steam. The lyes thus obtained are known as _spent lyes_, from +which the glycerine is recovered. They should show an alkalinity of +approximately 0.5 per cent. if the operation is carefully carried out. + +The remaining tallow is now added and the above operations repeated. + +After the spent lyes have been drawn off, the soap is closed with water +and the proper percentage of rosin soap previously formed, or rosin +itself is added to the mass in the kettle. More lye is then allowed to +flow in until the mixture is up to "strength." This is usually tested +by the "bite" on the tongue of a small cooled sample. After boiling +until the steam comes through, the mass is grained with salt as before +and allowed to settle one and one-half to three hours. These lyes, known +as _strengthening lyes_ are run to storage to be used subsequently with +fresh fat to take up the caustic soda contained therein. + +The soap is now ready for finishing and is first boiled through and +tried for strength. A drop of phenolphthalein (1 per cent. +phenolphthalein in 98 per cent. alcohol) is allowed to drop on the +molten soap taken up on a trowel. The red color should be instantly +produced and develop to a full deep crimson in a few seconds, or more +lye must be added until this condition is realized. Should it flash a +deep crimson immediately it is on the strong side. This cannot be +conveniently remedied; it can only serve as a guide for the next boil, +but in any case it is not of any serious consequence, unless it is too +strong. + +With the steam on, the soap is now examined with a trowel which must be +thoroughly heated by working it about under the surface of the hot soap. +The appearance of the soap as it runs from the face of the trowel +indicates its condition. It is not possible to absolutely describe the +effect, which can only be properly judged by practice, yet the following +points may serve as a guide. The indications to be noticed are the shape +and size of the flakes of soap as the sample on the trowel breaks up and +runs from the hot iron surface, when the latter is turned in a vertical +position, as well as the condition of the iron surface from which the +soap flakes have fallen. A closed soap will run slowly into a +homogeneous sheet, leaving the trowel's surface covered with a thin +layer of transparent soap; a grained mass will run rapidly down in tiny +grains, about one-half an inch in diameter or less, leaving the hot +trowel absolutely dry. The object of the finish is to separate the +soaps of the lower fatty acids from those of the higher, and both from +excess of liquid. A point midway between "open" and "closed" is required +to arrive at this point. + +Having arrived at the above condition, the soap is allowed to settle +anywhere from one to three days and then run off through the skimmer +pipes to the nigre and framed or pumped to the tank feeding the drying +machine. + +The stock thus obtained should be fairly white, depending upon the grade +of tallow used and slightly alkaline to an alcoholic phenolphthalein +solution. If removed at exactly the neutral point or with a content of +free fat the soap will sooner or later develop rancidity. The soap thus +obtained is an ordinary tallow base, and the one by far greatest used in +the manufacture of toilet soaps. The percentage of cocoanut oil +indicated is not fixed and may readily be varied, while in fine toilet +soap the rosin is usually eliminated. + +In the manufacture of full boiled soda soaps in which no glycerine is +obtained as a by-product, it being retained in the soap itself, the soap +formed is known as a "run" soap. The process is used most extensively in +the manufacture of marine soaps by which the method may be best +illustrated. This soap is known as marine soap because of its property +of readily forming a lather with salt water and is mostly consumed +aboard vessels. + +Marine soaps are manufactured by first placing in the kettle a +calculated amount of lye of 25 deg. to 35 deg. B., depending upon the +amount of moisture desired in the finished soaps, plus a slight excess +required to saponify a known weight of cocoanut oil. With open steam on, +the cocoanut oil is then gradually added, care being taken that the soap +does not froth over. Saponification takes place readily and when the oil +is entirely saponified the finished soap is put through the process +known as running. This consists in constantly pumping the mass from the +skimmer pipe back into the top of the kettle, the object being to +prevent any settling of the nigre or lye from the soap, as well as +producing a homogeneous mass. It is customary to begin the +saponification in the morning, which should be completed by noon. The +soap is then run for about three hours and framed the next morning. +After having remained in the frame the time required to solidify and +cool, the soap is slabbed and cut into cakes. This process is difficult +to carry out properly, and one not greatly employed, although large +quantities of marine soap are purchased by the government for use in the +navy and must fulfill certain specifications required by the purchasing +department. + +In making potash soaps it is practically impossible to obtain any +glycerine directly because of the pasty consistency of the soap, and no +graining is possible because the addition of salt to a soft soap, as +already explained, would form a soda soap. Large quantities of soft +soaps are required for the textile industries who desire mostly a strong +potash soap, and the large number of automobiles in use at the present +time has opened a field for the use of a soft soap for washing these. A +soap for this purpose must be neutral so as not to affect the varnish or +paint of automobiles. + +A suitable soap for textile purposes may be made as follows: + + Red oil 80 parts + House grease 20 parts + Caustic soda lye, 36 degs. B. 3 parts + Carbonate of potash 5-1/2 parts + Caustic potash 23-1/4 parts + +Olive oil, corn oil, soya bean oil, olive oil foots or cottonseed oil +may replace any of the above oils. A large quantity of cottonseed oil +will cause the soap to fig. + +To carry out the process, the caustic potash and carbonate of potash are +dissolved and placed in the kettle together with the soda lye, and the +oils added. This is most satisfactorily accomplished by being finished +the day before the boiling is begun. The next day the boiling is begun +and water added to bring the soap up to the desired percentage of fatty +acid, due allowance being made for the water formed by the condensation +of the open steam in boiling. Care must be taken that the soap in the +kettle does not swell and run over during the saponification. A good +procedure is to use open steam for a period of about two hours, then +close the valve and allow the saponification to continue without +boiling, and repeat this until it is entirely saponified. After the +saponification has been completed the soap is briskly boiled all day and +the proper corrections made; that is, if too alkaline, more oil is +added, and if free fat is present, more potash. About 2 per cent. +carbonate of potash is the proper amount for a soap containing 50 per +cent. fatty acid. The soap is sampled by allowing it to drop on a clean, +cold glass surface. In so doing, the soap should not slide or slip over +the glass surface when pressed thereon, but should adhere to the glass, +or it is too alkaline. A sample worked between the fingers showing too +much stringiness should have more strong potash and oil added. A sample +taken out in a pail and allowed to cool over night will serve as a guide +as to the body of the soap in the kettle. When the soap has thus been +properly finished it is run into barrels. + +For an automobile soap the following is a good working formula: + + Corn oil 1,000 parts + Potash lye, 31-1/2 degs. B. 697 parts + +Proceed as in the directions just given for textile soap in placing +charge in the kettle. When the kettle is boiling up well, shut off the +steam and the saponification will complete itself. The soap may be run +into the barrels the next day. + +A heavy soap with a smaller percentage of fat may be made as follows: + + Corn oil 1,000 parts + Potash lye, 24-1/2 degs. B. 900 parts + +Boil until the soap bunches, and shovel the finished soap into barrels. +Upon standing it will clear up. By the addition of more water the yield +of soap per pound of oil may be run up to 300 per cent. + +After soft soaps have been allowed to stand for some time the phenomenon +known as "figging" often occurs. This term is applied to a +crystalline-like formation, causing spots of a star-like shape +throughout the soap. This is undoubtedly due to the stearine content of +the soap crystallizing out as it cools, and forming these +peculiarly-shaped spots. It more generally occurs in the winter and may +be produced artificially by adding a small quantity of soda to the +potash lye before saponification. + +The oils usually employed in the manufacture of potash soaps are +cottonseed oil, corn oil, soya bean oil, olive oil foots, red oil, +cocoanut oil, grease and the various train oils. The usual percentage +yield is from 225 per cent. to 300 per cent., based upon the weight of +oil used. In calculating the weight of a soft soap it is to be +remembered that since potassium has a higher molecular weight (56) than +sodium (40), the corresponding soap formed is that much greater in +weight when compared with a sodium soap. Rosin may be added to soft +soaps as a cheapening agent. + + +COLD PROCESS. + +The cold process for manufacturing soap is the simplest method of soap +making, and the equipment required is small when compared to the other +methods. All the more expensive equipment that is necessary is a +crutcher, a tank to hold the lye, frames, a slabber or cutting table, +and a press. Yet, in spite of the simplicity of thus making soap, the +disadvantages are numerous for the production of a good piece of soap. +The greatest difficulty is to obtain a thorough combination of oil or +fat and lye so that there will not be an excess of one or the other in +the finished soap. At its best there is either a considerable excess of +free fat which later exhibits itself in producing rancidity or +uncombined caustic, which produces an unpleasant effect on the skin when +the soap is consumed for washing. The latter objection, of course, can +only be applied to toilet soaps. + +Cocoanut oil is used very largely in the manufacture of cold-made soaps +as it is well adapted for this purpose, although it is by no means true +that other oils may not be employed. Since by this process of +manufacture no impurity contained in the fat or oil is removed in the +making of the soap, it is necessary that in order to obtain a fine +finished product, any impurity contained in these may be removed if +present, or that the fats be as pure as can be obtained. If inedible +tallow is used for cold-made soap, it is advisable to bleach it by the +Fuller's Earth Process. + +The carrying out of this method is best illustrated by an example of a +cold-made cocoanut oil soap. + + Charge: + + Cochin cocoanut oil 846 parts + Lye (soda), 35 degs. B. 470 parts + Water 24 parts + +The oil is run into the crutcher and the temperature of the oil raised +to 100 degs. F. by dry steam. The lye and water are at room temperature. +After all the oil is in the crutcher, the lye and water are slowly added +to prevent any graining of the soap. Toward the end the lye may be added +more rapidly. When all the lye is in, the mass is crutched for about +three hours, or until upon stopping the crutcher a finger drawn over the +surface of the soap leaves an impression. If this condition is not +realized, the soap must be mixed until such is the case. Having arrived +at this point, the mixture is dropped into a frame which should remain +uncovered. The heat produced by the further spontaneous saponification +will cause the soap to rise in the middle of the frame. After having set +for some days it is ready to be slabbed and cut into cakes. + +A potash soap may be made by the cold process just as readily as a soda +soap. Soaps of this type may be made by either of these formulae in a +crutcher: + + Olive oil foots 600 + Potash lye, 18 degs. B. hot, 20 degs. B. cold 660 + + or + + Corn oil 800 + Rosin 200 + Potash lye, 27 degs. B. 790 + Water 340 + +Heat the oils to 190 degs. F., add the lye and crutch until the soap +begins to bunch, when it is ready to be run into barrels where the +saponification will be completed. + +Semi-boiled soaps differ from those made by the cold process in +temperature. In making semi-boiled soaps the fats are usually heated to +140° F. The addition of the lye raises the temperature to 180°--200° F. +when saponification takes place. + + +CARBONATE SAPONIFICATION. + +The method of the formation of soap by the utilization of the fatty acid +directly, from which the glycerine has already been removed by some +method of saponification other than with caustic soda, and neutralizing +this with alkali, is becoming increasingly popular. The glycerine is +more easily recovered from a previous cleavage of the fats or oils, but +a soap made from the mixed fatty acids thus obtained is seldom white in +color and retains an unpleasant odor. Since soda ash or sodium carbonate +is cheaper than caustic soda and readily unites with a fatty acid, it is +used as the alkali in the carbonate saponification. The process is +similar to that already given under Rosin Saponification. About 19 per +cent. by weight of the fatty acids employed of 58 per cent. soda ash is +dissolved in water until it has a density of 30 degs. B., and the +solution is run into the kettle, which is usually equipped with a +removable agitator. The fatty acids, previously melted, are then slowly +added while the mixture is boiled with open steam and agitated with the +stirring device. The fatty acids instantly unite with the carbonate and +rise in the kettle, due to the generation of carbon dioxide, and care +must be exercised to prevent boiling over. After all the fatty acid has +been added, and the mass is boiled through the saponification must be +completed with caustic soda, as there is as yet no practical method +known which will split a fat entirely into fatty acid and glycerine. +Thus about 10 per cent. of the fatty acids are true neutral fats and +require caustic soda for their saponification. This is then added and +the soap completed, as in full-boiled soaps. + +In carrying out this method upon a large scale, large +sue\Neanderthal\doroteer\Neanderthal\Josephine\ quantities of carbon +dioxide are formed during the boiling of the soap, which replaces a +quantity of the air contained therein. The kettle room should therefore +be well ventilated, allowing for a large inflow of fresh air from out of +doors. + + + + +CHAPTER IV + +Classification of Soaps. + + +In considering the many different varieties of soaps, their +classification is purely an arbitrary one. No definite plan can be +outlined for any particular brand to be manufactured nor can any very +sharp distinction be drawn between the many soaps of different +properties which are designated by various names. It is really a +question to what use a soap is to be put, and at what price it may be +sold. There is, of course, a difference in the appearance, form and +color, and then there are soaps of special kinds, such as floating +soaps, transparent soaps, liquid soaps, etc., yet in the ultimate sense +they are closely allied, because they are all the same chemical +compound, varying only in their being a potash or soda soap, and in the +fatty acids which enter into combination with these alkalis. Thus we can +take a combination of tallow and cocoanut oil and make a great many +presumably different soaps by combining these substances with caustic +soda, by different methods of manufacture and by incorporating various +other ingredients, as air, to form a floating soap, alcohol to make a +transparent soap, dyestuffs to give a different color, etc., but +essentially it is the same definite compound. + +The manufacturer can best judge the brand of soaps he desires to +manufacture, and much of his success depends upon the name, package, +shape, color or perfume of a cake of soap. It is the consumer whom he +must please and many of the large selling brands upon the market today +owe their success to the above mentioned details. The great majority of +consumers of soap know very little concerning soap, except the fact +that it washes or has a pleasant odor or looks pretty, and the +manufacturer of soap must study these phases of the subject even more +carefully than the making of the soap itself. + +For a matter of convenience we will classify soap under three general +divisions: + +I. Laundry soaps, including chip soaps, soap powders and scouring soaps. + +II. Toilet soaps, including floating soap, castile soap, liquid soap, +shaving soap, etc. + +III. Textile soaps. + + +LAUNDRY SOAP. + +The most popular household soap is laundry soap. A tremendous amount of +this soap is consumed each day in this country, and it is by far +manufactured in larger quantities than any other soap. It is also a soap +which must be sold cheaper than any other soap that enters the home. + +The consumers of laundry soap have been educated to use a full boiled +settled rosin soap and to make a good article at a price this method +should be carried out, as it is the one most advisable to use. The +composition of the fats entering into the soap depends upon the market +price of these, and it is not advisable to keep to one formula in the +manufacture of laundry soap, but rather to adjust the various fatty +ingredients to obtain the desired results with the cheapest material +that can be purchased. It is impossible to use a good grade of fats and +make a profit upon laundry soap at the price at which it must be +retailed. The manufacturer of this grade of soap must look to the +by-product, glycerine, for his profit and he is fortunate indeed if he +realizes the entire benefit of this and still produces a superior piece +of laundry soap. + + +SEMI-BOILED LAUNDRY SOAPS. + +It is advantageous at times to make a laundry soap by a method other +than the full boiled settled soap procedure as previously outlined. This +is especially the condition in making a naphtha soap, in which is +incorporated naphtha, which is very volatile and some of the well known +manufacturers of this class of soap have adopted this process entirely. +A laundry soap containing rosin cannot be advantageously made by the +cold process, as the soap thus made grains during saponification and +drops a portion of the lye and filling materials. By making a +semi-boiled soap this objection is overcome. The half boiled process +differs from the cold process by uniting the fats and alkalis at a +higher temperature. + +To carry out this process the following formulae have been found by +experience to give satisfactory results. + + I. lbs. + + Tallow 100 + Rosin 60 + Soda Lye, 36° B. 80 + + II. + + Tallow 100 + Rosin 60 + Silicate of Soda 25 + Soda Lye, 36° B. 85 + + III. + + Tallow 100 + Rosin 100 + Lye, 36° B. 105 + Silicate of Soda 25 + Sal Soda Solution 20 + +In any of these formulas the sodium silicate (40° B.) may be increased +to the same proportion as the fats used. By so doing, however, twenty +pounds of 36° B. lye must be added for every hundred pounds of silicate +additional to that indicated or in other words, for every pound of +silicate added 20 per cent. by weight of 36° B. lye must be put into the +mixture. The rosin may also be replaced by a previously made rosin soap. + +To make a semi-boiled soap, using any of the above formulae, first melt +the rosin with all or part of the fat, as rosin when melted alone +readily decomposes. When the mixture is at 150° F. run it into the +crutcher and add the lye. Turn on sufficient dry steam to keep the +temperature of the soap at about 150° F. in the winter or 130° F. in +summer. After the mass has been mixed for half an hour, by continuously +crutching the soap it will at first thicken, then grain and it may again +become thick before it becomes smooth. When the mass is perfectly smooth +and homogeneous drop into a frame and crutch in the frame by hand to +prevent streaking. After standing the required length of time the soap +is finished into cakes as usual. + + +SETTLED ROSIN SOAP. + +Settled rosin soaps are made from tallow, grease, cottonseed oil, +bleached palm oils of the lower grades, corn oil, soya bean oil, arachis +oil, distilled garbage grease, cottonseed foots or fatty acids together +with an addition of rosin, varying from 24 per cent. to 60 per cent. of +the fatty acids which should titer from 28 to 35. A titer lower than 28 +will prevent the finished kettle of soap from being capable of later +taking up the filling materials. As has already been stated under +hardened oils, these being very much higher in titer allow a greater +percentage of rosin to be added. Thus hardened fish oils and cottonseed +oil are gradually being more extensively employed in soaps of this +character. + +The procedure of handling the kettle is similar to that given under full +boiled soap. The stock is steamed out into a settling tank and allowed +to settle over night, after which it is pumped into the soap kettle. +Having stocked the kettle, open steam is turned on and 10°-12° B. lye is +run in, while using a steam pressure of ninety to one hundred pounds in +order to prevent too great a quantity of condensation of the steam, the +water thus being formed weakening the lye. If a steam pressure of fifty +to sixty pounds is available, a stronger lye (20° B.) should be added. +Care must be taken not to allow the lye to flow in too rapidly or the +soap will not grain. The saponification is only attained by prolonged +boiling with sufficient lye of proper strength. When saponification has +taken place, the mass begins to clear and a sample taken out with a +paddle and cooled should show a slight pink with a 1 per cent. alcoholic +phenolphthalein solution. + +It may be stated here that in using this indicator or any other to test +the alkalinity of soap, the soap should always be cooled and firm, as +whenever water is present, the dissociation of the soap thereby will +always react alkaline. When this state is reached the mass is ready for +graining, which is accomplished by distributing salt brine or pickle or +spreading dry salt over the surface of the soap. The kettle is then +thoroughly boiled until the mass shows a soft curd and the lye drops +clearly from a sample taken out with a trowel or paddle. The steam is +then shut off and the soap allowed to settle over night. The lyes are +then run off to the spent lye tank for glycerine recovery. In +saponifying a freshly stocked kettle it is apt to bunch. To prevent this +salt is added at various times to approximately one per cent. of the fat +used. + +If, by any possibility the soap has bunched, this condition may be +remedied by the addition of more strong lye and boiling until it is +taken up. To work a kettle to its full capacity it is advisable to make +two "killing" changes. First add about 75 per cent. of the fat and grain +as directed. Run off the spent lyes and then add the remainder of the +stock and repeat the process. When the spent lye has been run to +storage, the open steam is again turned on and 18° B. lye gradually +allowed to run in. The rosin is now broken up and put into the kettle, +or a previously made rosin soap is pumped in. + +Lye is then added until the soap has a sharp taste after about three +hours of continuous boiling, or when the soap is in the closed state. +More lye should then be run into the kettle to grain the soap well, the +grain not being too small. Then allow the soap to settle over night and +draw off the strengthening lye. The next day again boil up the kettle +and add water until the soap thins out and rises or swells high in the +kettle. A sample taken out at this stage upon a hot trowel should run +off in large flakes. The surface of the soap should be bright and shiny. + +If the sample clings to the trowel, a slight addition of lye will remedy +this defect. The kettle is then allowed to rest, to drop the nigre and +to cool for some time, depending upon the size of the kettle. The proper +temperature is such that after having been pumped to the crutcher and +the filling materials having been added, a thermometer placed into the +mass should indicate 128°-135° F. after the crutcher has run from ten to +fifteen minutes. The filling material may consist of from 7-9 per cent. +of sal soda solution, 36°-37° B. warm or just enough to close up the +soap and make it rise high in the center of a screw crutcher and make it +cling close to a warm trowel. Other fillers such as outlined below are +added at this point. + +An addition of from 2-3 per cent. of a special mineral oil for this +purpose will impart a finish to the soap and 3-5 per cent. starch added +prevents the soap from cracking in the frames. Other filling material as +silicate of soda, borax, talc or silex are used. After the filling +material has been thoroughly crutched through the soap it is framed, +and, after being several days in the frame to solidify and cool the soap +is ready for slabbing, pressing and wrapping. + +In order to more definitely illustrate the composition of the mixture of +fats and oils entering into the formation of a laundry soap a typical +formula may be given for such a soap containing 40 per cent. rosin added +to the amount of fats used: + + lbs. + Grease 7,000 + Tallow 4,000 + Corn Oil 7,000 + Cottonseed Oil 3,000 + Rosin 8,400 + +The following have been found to be satisfactory filling materials and +are calculated upon the basis of a 1,400-pound frame of soap. + + I. lbs. + + Sodium Silicate, 38°-40° B. 100 + Mineral Oil 25 + Sal Soda Solution, 36° B. 80 + Borax 1 + + II. + + Sal Soda Solution, 36° B. 80 + Mineral Oil 25 + Sodium Silicate 60 + + III. + Soda Ash 10 + Sal Soda 55 + Sodium Silicate 115 + Mineral Oil 40 + Brine (Saturated Solution) 10 + Sodium Silicate, 38°-40° B. 100 + + IV. + Sodium Silicate 100 + Silex or Talc 200 + Soda Ash 50 + + V. + + Sal Soda Solution, 36° B. 90 + Sodium Silicate 50-60 + Mineral Oil 25 + Borax Solution, 25° B. (hot) 15 + + +CHIP SOAP. + +Chip soap is used extensively in laundries but is also used largely in +other branches. It may be made either as a settled soap or by the cold +made process. + +To make a full boiled settled chip soap, proceed as directed under +settled laundry soap. The kettle is stocked with light grease or a +mixture of grease with corn oil or other cheap oils. For this kind of +soap the rosin is eliminated. + +Chip soap may be filled as well as laundry soap. This is done in the +crutcher and the following adulterations are suitable. + + lbs. + Settled Soap 700 + Soda Ash 35 + Sodium Silicate 215 + or + Settled Soap 700 + Silicate of Soda 560 + Soda Ash 18 + Carbonate of Potash, 26° B. 50 + +The cheapest method of drying is by running this soap through a drying +machine and this is the procedure usually carried out for making dried +chip soap. + + +COLD MADE CHIP SOAPS. + +To make chip soaps by the cold process a sweet tallow of low percentage +of free fatty acid should be employed. The tallow is heated to 120° to +135° F. and the lye run in slowly at first and then the silicate of soda +is added. The mass is then mixed until a finger drawn through the soap +leaves a slight impression, then dropped into frames or barrels. Soaps +containing a small percentage of fat should be well covered in the frame +for twenty-four hours to retain their heat and insure proper +saponification. The following formulae are suitable: + + I. lbs. + Tallow 1,200 + Soda Lye, 35° B. 850 + Sodium Silicate 750 + + II. + Tallow 475 + Ceylon Cocoanut Oil 100 + Soda Lye, 37° B. 325 + Potash Lye, 37° B. 56 + + III. + Tallow 500 + Soda Lye, 37-1/2° B. 297 + Sodium Silicate 416 + Potash Lye, 37-1/2° B. 37-1/2 + + IV. + Tallow 450 + Soda Lye, 37-1/2° B. 255 + Sodium Silicate 450 + Potash Lye, 37-1/2° B. 50 + + V. + Tallow 450 + Soda Lye, 35° B. 470 + Sodium Silicate 650 + + VI. + Tallow 420 + Sodium Silicate 600 + Soda Lye, 37-12° B. 270 + + +UNFILLED CHIP SOAP. + +A very good grade of chip soap is made by employing no filling material +whatsoever, but unfortunately the price of this soap has been cut to +such an extent that these can not compete with a filled chip. A number +of the best soaps of this kind are made from a settled soap using a +light grease with corn oil. A soap of this nature is made as follows. + + lbs. + Settled Soap 800 + Sal Soda Solution, 36°-37° B. 252 + Soda Ash 182 + +If this soap is run into frames it may be stripped and chipped in two +days. + + +SOAP POWDERS. + +Soap powders have become so great a convenience as a general cleansing +agent that to eliminate them from the household necessities would mean +much unnecessary energy and work to the great number of consumers of +this product. They may be manufactured so cheaply and still be +efficient, that their use has almost become universal for cleansing and +scouring purposes. The uses to which soap and scouring powders are +adapted are too well known to enter into a description of their +employment. Since they offer a greater profit to the manufacturer than +ordinary household soap, many brands are extensively advertised. + +Numerous combinations for soap powders might be cited and it is a simple +matter to vary the ingredients as to fat content and manufacture a +powder of this sort as low as a cent a pound. Many substances are +incorporated with soap, such as salt, soda ash, tripoli, crushed +volcanic deposits, ground feldspar, infusorial earth of various kinds, +silex, etc. In addition to these various fillers, compounds with true +cleansing and bleaching properties, in addition to soap, are added, such +as the salts of ammonium (sal ammoniac, carbonate of ammonia), sodium +perborate and the peroxides of various metals. The public, however, have +been accustomed to receive a large package of soap or scouring powder +for a small amount of money and it is a difficult matter for the +manufacturer to add more expensive substances of this nature to his +product, to increase its efficiency, without raising the price or +decreasing the size of the package. + +In manufacturing soap powders, the dried soap chips might be mixed with +the filler and alkali and then pulverized. This method is not +extensively employed nevertheless. The process which is the most +economical is one whereby the ingredients are mixed in a specially +adapted mixer for heavy material until dry and then run directly to the +crusher and pulverizer, after which it is automatically packed, sealed +and boxed. Another method of procedure is to run out the mixture from +the crutcher to the frames, which are stripped before the soap cools, +and is cut up at once, for if it hardens it could not be cut with wires. +It is better, however, to run the mixture into sheets upon a specially +constructed floor and break up the mass when cool. + +Formulae for soap powders which have been found to be suitable for +running dry in the mixer follow: + + I + Soda ash, 58 per cent. 42 lbs. + Silica 220 " + Settled soap (usually cottonseed). 25 " + Salt 10 " + + II + Soap (settled cottonseed) 40 lbs. + Soda ash, 58 per cent. 60 " + + III + Settled soap 100 lbs. + Soda ash, 58 per cent. 400 " + +Fillers in varying proportions may replace the soda ash in the above +formulae. It is of course understood that the soap has been previously +made and run as molten soap into the crutcher. + +The following soap powders will not dry up in the crutcher upon running, +but are of the class which may be framed or run on the floor to +solidify: + + + I + Soap 850 lbs. + Filler 400 " + Sal soda solution, 20 degs. B 170 " + + II + Soap 650 lbs. + Filler 550 " + Sal soda solution, 20 degs. B. 340 " + + III + Soap 80 lbs. + Filler 550 " + Sal soda solution 170 " + + IV + Soap (settled tallow) 800 lbs. + Filler 400 " + Sal soda solution 170 " + Water 100 " + + V + +First saponify 100 parts house grease and 100 parts ordinary grease and +make a run soap. Then use in crutcher either: + + Soap 400 lbs. + Filler 575 " + Hot water 60 " + or + Soap 200 lbs. + Hot water 200 " + Filler 625 " + +It would be a simple matter to write numerous additional formulae, but +the above are typical. The manufacturer must judge for himself just what +filling material to use. The filler indicated in the above formulae is +therefore left open. A few formulae for more expensive powders than +those given recently appeared among others in the "Seifensieder +Zeitung"[9]: + + + I + + Powdered soap 90 lbs. + Sodium perborate 10 " + +The perborate should be added when the powder is perfectly dry or it +loses its bleaching properties. + + II + + Soap powder, 20 per cent. fat. + Cocoanut oil fatty acids 25 lbs. + Olein 25 " + Bone fat 70 " + Soda lye, 30 degs. B. 90 " + Water 150 " + Ammonium carbonate 125 " + + III + + Soap powder, 10 per cent. fat. + Cocoanut oil fatty acids 20 lbs. + Olein 10 " + Bone fat 20 " + Soda lye, 30 degs. B. 30 " + Water 175 " + Ammonium carbonate 175 " + + +LIGHT OR FLUFFY POWDERS. + +Light or fluffy powders containing 35-45% moisture can be made in two +ways. The first method requiring a minimum equipment is to mix the +powder and sal soda in a mixer, allow it to stand in frames for a week +to crystallize or spread it on the floor for a few hours to dry and then +grinding it. + +The continuous method finishes the powder in a few minutes and with a +minimum amount of labor. By this process the various ingredients, soap, +soda ash solution, etc., are measured, run by gravity into the mixer, +mixed and the molten mass run over the crystallizer or chilling rolls +thru which either cold water or brine is pumped. From the roll the +powder is scraped off clean by a knife, passes to a screen which sends +the tailings to a grinder, falls into a storage bin from whence it is +weighed and packed by an automatic weighing machine into cartons made up +in most cases by another machine. Due to the large percentage of +moisture contained in these soap powders the carton is generally wrapped +in wax paper to aid in the prevention of the escape of moisture. + + +SCOURING POWDERS. + +Scouring powders are very similar to soap powders and differ only in the +filler used. We have already considered these fillers under scouring +soap, from which they do not differ materially. They are usually +insoluble in water to aid in scouring. The mixer used for substances of +this kind in incorporating the soap and alkali must be of strong +construction. + + +SCOURING SOAP. + +Scouring soaps resemble soap powders very closely in their composition, +in that they are a combination of soap and filling material. Since more +lather is required from a scouring soap than in soap powders, a cocoanut +oil soap is generally used. The usual filling material used is silex. +The greatest difficulty in the manufacture of scouring soap is the +cracking of the finished cake. This is usually due to the incorporation +of too great an amount of filler, or too high a percentage of moisture. + +In manufacturing these soaps the cocoanut oil is saponified in the +crutcher with 38 degs. B. lye, or previously saponified as a run soap, +as already described under "Marine Soaps." To twenty-five parts of soap +are added a percentage of 38 degs. B. sal soda or soda ash solution, +together with a small quantity of salt brine. To this mixture in the +crutcher seventy-five parts of silex are then added, and a sufficient +amount of hot water to make the mass flow readily. Care must be +exercised to not add too great a quantity of water or the mass will +crack when it cools. The mass is then framed and cut before it sets, or +poured into molds and allowed to set. While silex is the most +extensively used filler for scouring soaps, it is feasible to +incorporate other substances of like character, although it is to be +remembered that the consumer is accustomed to a white cake, such as +silex produces. Any other material used to replace silex should also be +as fine as this product. + + +FLOATING SOAP. + +Floating soap occupies a position midway between laundry and toilet +soap. Since it is not highly perfumed and a large piece of soap may be +purchased for small cost, as is the case with laundry soap, it is +readily adaptable to general household use. Floating soap differs from +ordinary soap in having air crutched into it which causes the soap to +float in water. This is often advantageous, especially as a bath soap, +and undoubtedly the largest selling brand of soap on the American market +today is a floating soap. + +In the manufacture of floating soap a high proportion of cocoanut oil is +necessary. A most suitable composition is one part cocoanut oil to one +part of tallow. This is an expensive stock for the highest grade of soap +and is usually cheapened by the use of cottonseed or various other +liquid oils. Thus it is possible to obtain a floating soap from a kettle +stocked with 30 per cent. cocoanut oil, 15 per cent. cottonseed oil and +55 per cent. tallow. With this quality of soap, however, there is a +possibility of sweating and rancidity, and of the soap being too soft +and being poor in color. + +The process of manufacture is to boil the soap in an ordinary soap +kettle, after which air is worked into the hot soap by a specially +constructed crutcher, after which the soap is framed, slabbed, cut into +cakes and pressed. + +Concerning the boiling of the soap, the saponification must be carefully +carried out, as the high proportion of cocoanut oil may cause a violent +reaction in the kettle causing it to boil over. + +The method of procedure is the same as for a settled soap up to the +finishing. When the mass is finally settled after the finish, the soap +should be more on the "open" side, and the object should be to get as +long a piece of goods as possible. + +Due to its high melting point, a much harder crust forms on the surface +of a floating soap and in a greater proportion than on a settled soap +during the settling. In a large kettle, in fact, it has been found +impossible to break through this crust by the ordinary procedure to +admit the skimmer pipe. Much of the success of the subsequent operations +depends upon the completeness of the settling, and in order to overcome +the difficulties occasioned by the formation of the crust everything +possible should be done in the way of covering the kettle completely to +enable this period of settling to continue as long as possible. + +When the soap is finished it is run into a specially constructed U-shape +crutcher, a Strunz crutcher is best adapted to this purpose, although a +rapidly revolving upright screw crutcher has been found to give +satisfaction upon a smaller scale, and a sufficient quantity of air +beaten into the soap to make it light enough to float. Care must be +taken not to run the crutcher too rapidly or the soap will be entirely +too fobby. During this operation the mass of soap increases in bulk, +and after it has been established how much air must be put into the soap +to satisfy the requirements, this increase in bulk is a criterion to +estimate when this process is completed. + +It is of course understood that the longer the crutching continues the +greater quantity of air is incorporated and the increase of volume must +be established for a particular composition by sampling, cooling the +sample rapidly and seeing if it floats in water. If the beating is +continued too long an interval of time, the finished soap is too spongy +and useless. + +The temperature of the mass during crutching is most important. This +must never exceed 158 degrees F. At 159 degrees F. the operation is not +very successful, yet the thermometer may indicate 140 degrees F. without +interfering with this operation. If, however, the temperature drops too +low, trouble is liable to be met with, by the soap solidifying too +quickly in the frames. + +When the crutching is completed, the soap is allowed to drop into frames +through the valve at the bottom of the crutcher and rapidly crutched by +the hand in the frames to prevent large air spaces and then allowed to +cool. It is an improvement to jolt the frames as they are drawn away as +this tends to make the larger air bubbles float to the surface and thus +reduce the quantity of waste. When the soap has cooled, the frame is +stripped and the soap slabbed as usual. At this point a layer of +considerable depth of spongy soap will be found to have formed. This of +course must be cut away and returned to the kettle. The last few slabs +are also often rejected, inasmuch as the weight of the soap above them +has forced out so much of the air that the soap no longer floats. As a +fair average it may be estimated that not more than 50 to 60 per cent. +of the soap in the kettle will come out as finished cakes. the +remaining 40 to 50 per cent. being constituted by the heavy crust in the +kettle, the spongy tops, the bottom slabs and scrapings. This soap is of +course reboiled and consequently not lost, but the actual cakes obtained +are produced at a cost of practically double labor. + +It is advisable to add a small quantity of soap blue color to the mass +while crutching to neutralize the yellowish tint a floating soap is +liable to have. + +Some manufacturers add a percentage of carbonate of soda, about 3 per +cent., to prevent the soap from shrinking. Floating soap may also be +loaded with sodium silicate to the extent of about 5 per cent. + + +TOILET SOAP. + +It is not a simple matter to differentiate between toilet soaps and +various other soaps, because numerous soaps are adaptable to toilet +purposes. While some soaps of this variety are manufactured by the cold +made or semi-boiled process, and not milled, the consumer has become +accustomed to a milled soap for general toilet use. + +The toilet base most extensively employed is a tallow and cocoanut base +made as a full boiled settled soap. The manufacture of this base has +already been outlined and really needs no further comment except that it +is to be remembered that a suitable toilet soap should contain no great +excess of free alkali which is injurious to the skin. Cochin cocoanut +oil is preferable to the Ceylon cocoanut oil or palm kernel oil, to use +in conjunction with the tallow, which should be a good grade and color +if a white piece of goods is desired. The percentage of cocoanut oil may +be anywhere from 10 to 25 per cent., depending upon the kind of lather +required, it being remembered that cocoanut oil increases the lathering +power of the soap. + +In addition to a tallow base, numerous other oils are used in the +manufacture of toilet soaps, especially palm oil, palm kernel oil, olive +oil and olive oil foots, and to a much less extent arachis or peanut +oil, sesame oil and poppy seed oil, oils of the class of cottonseed, +corn and soya bean oils are not adapted to manufacturing a milled soap, +as they form yellow spots in a finished cake of soap which has been kept +a short time. + +Palm oil, especially the Lagos oil, is much used in making a palm base. +As has already been stated, the oil is bleached before saponification. A +palm base has a yellowish color, a sweetish odor, and a small quantity +added to a tallow base naturally aids the perfume. It is especially good +for a violet soap. The peculiarity of a palm oil base is that this oil +makes a short soap. By the addition of some tallow or twenty to +twenty-five per cent. of cocoanut oil, or both, this objection is +overcome. It is a good plan in using a straight palm base to add a +proportion of yellow color to hold the yellowish tint of this soap, as a +soap made from this oil continues bleaching upon exposure to air and +light. + +Olive oil and olive oil foots are used most extensively in the +manufacture of castile soaps. The peculiarity of an olive oil soap is +that it makes a very slimy lather, and like palm oil gives the soap a +characteristic odor. An olive oil soap is usually considered to be a +very neutral soap and may readily be superfatted. Much olive oil soap is +used in bars or slabs as an unmilled soap and it is often made by the +cold process. Peanut oil or sesame and poppy seed oil often replaces +olive oil, as they form a similar soap to olive oil. + +In the manufacture of a toilet soap it is hardly practical to lay down a +definite plan for the various bases to be made. From the combination of +tallow, palm oil, cocoanut oil, palm kernel oil, olive oil and olive oil +foots, a great many bases of different proportions might be given. The +simplest method is to make a tallow base, a palm base and an olive oil +base. Then from these it is an easy matter to weigh out any proportion +of these soap bases and obtain the proper mixture in the mill. If, +however, as is often the case, a large quantity of soap base of certain +proportions of these, four or even more of these fats and oils is +required, it is not only more economical to stock the kettle with the +correct proportion of these oils, but a more thorough mixture is thus +obtained by saponifying these in the kettle. In view of the fact that it +is really a question for the manufacturer to decide for himself what +combination of oils he desires for a particular soap we will simply +outline a few typical toilet soap bases in their simplest combination. +It is understood that these soaps are suitable for milled soaps and are +to be made as fully boiled settled soaps. Palm kernel oil may be +substituted for cocoanut oil in all cases. + + +TALLOW BASE. + + Tallow 75-90 parts + Cocoanut oil 25-10 parts + + +PALM BASE. + + Bleached Lagos palm oil 75-80 parts + Cocoanut oil 25-20 parts + + or + + Tallow 30 parts + Palm oil 60 parts + Cocoanut oil 10 parts + + +OLIVE OIL BASE (WHITE). + + Olive oil 75-90 parts + Cocoanut oil 25-10 parts + + or + + Olive oil 40 parts + Tallow 40 parts + Cocoanut 20 parts + +Where a green olive oil base is desired, olive oil foots are substituted +for the olive oil. Peanut oil may replace the olive oil or part of it, +the same being true of sesame oil and poppy seed oil. + + +PALM AND OLIVE BASE. + + Palm oil 50 parts + Olive oil 30 parts + Cocoanut oil 20 parts + + or + + Palm oil 20 parts + Olive oil 10 parts + Tallow 50 parts + Cocoanut oil 20 parts + + +CHEAPER TOILET SOAPS. + +It is often necessary to manufacture a cheaper grade of soap for toilet +purposes to meet the demand of a certain class of trade as well as for +export. To accomplish this it is of course necessary to produce a very +inferior product and run down the percentage of fatty acids contained in +the soaps by the addition of fillers or to use cheaper oils in +manufacturing. The most simple method of filling a soap is to load it at +the mill with some substance much less expensive than the soap itself. +Many of the cheaper toilet soaps, however, are not milled and it is, +therefore, necessary to follow out some other procedure. + +Milled soaps, as has just been stated, are loaded at the mill. The +consumers of cheaper toilet soaps in this country are accustomed to a +milled soap and this grade of soap for home consumption is very often +filled with numerous substances, but most generally by adding starch +and talc. The addition of such materials of course later exhibit +themselves by imparting to the cake of soap a dead appearance. Talc is +more readily detected in the soap than starch by washing with it, as +talc is insoluble and imparts a roughness to the soap, like sand or +pumice, as the soap wears down. It may readily be added to 20 per cent. +by weight. Starch is to be preferred to talc, in loading a soap, as it +is not so readily noticeable in washing. It leaves the cake itself +absolutely smooth although the lather formed is more shiny. This +substance may be employed to as high a percentage as one-third the +weight of the soap. It is, of course, possible to cheapen the best soap +base by this method and the price may be further lowered by using the +less expensive oils and fats to make the soap base. + + +RUN AND GLUED UP SOAPS. + +A very cheap grade of soap may be made by making a run soap and adding +the filler e. g. sodium silicate in the kettle during saponification. +The percentage of fatty acids may be brought down to 10 per cent., +although of course a soap of this type shrinks a whole lot upon +exposure. + +In making a "glued up" soap the procedure is the same for making the +soap itself as with a settled soap, except that the soap is finished +"curd" and later filled in the crutcher. The percentage of fatty acids +in a soap of this type is seldom below 50 per cent. + +The method of "gluing up" a soap is best illustrated by a typical soap +of this character in which the kettle is charged with the following +stock. + + Bleached palm oil 5 parts + Distilled grease 2 " + Cotton oil foots stock, 63% fatty acid 1 " + Rosin 4 " + +The palm oil is first run into the kettle, saponified and washed to +extract any glycerine, then the rest of the fats and finally the rosin. +The soap is then finished and settled as with a boiled settled soap. To +assure success it is absolutely necessary that the soap settle as long a +period as possible, or until the temperature is about 150 degs. F. The +ideal temperature for carrying out the "gluing up" process is 140 degs. +F., as at a lower temperature than this the soap is liable to cool too +quickly and not be thoroughly glued up. A higher temperature than 150 +degs. F. causes delay in that the soap does not properly take the filler +at a higher temperature and the soap must be kept in the crutcher until +the temperature drops to the right point. + +The soap is run into the crutcher and the percentage of fatty acids run +down to 50-55 per cent. with one of the following mixtures: + + Sodium silicate, 59-1/2° B. 1 part + Potassium carbonate, 51° B. 1 " + + or + + Sodium silicate, 59-1/2° B. 1 part + Potassium carbonate, 51° B. 1 " + Sodium sulfate, 28° B. 1 " + +From 230 to 300 pounds of either of these mixtures are required for a +crutcher holding 2,600 pounds of soap. + +The crutching is continued until the mass is well "spiked," that is to +say, a freshly broken surface of the soap, as the crutcher blade is +jerked away, stands up like shattered sheets in triangular form +[Transcriber's note: three triangles]), which retain their shape +perfectly. When this condition is realized the soap is run into frames +which are carefully crutched by hand to remove any air spaces. The +surface of the soap is then smoothed down and heaped up in the center. +After standing a day to contract, the surface is again leveled and a +snugly-fitting board placed on the top of the soap upon which a weight +is placed or upon which the workman treads and stamps until the surface +is flat, thus assuring the further removal of air spaces. The soap +remains in the frame from six to eight days and is then slabbed, barred +and pressed by the usual method employed for soaps thus handled without +milling. + +In a soap of this nature no hard and fast rule can be laid down as to +the quantity of solution to be used for "gluing up" or the strength of +the solution. In a soap of the type described the most satisfactory +appearing cake will be obtained from a soap containing 58 per cent. +fatty acids. That is to say, about 8 per cent. to 10 per cent. filling +solution is added per hundred pounds of soap. The filling solutions +given are very satisfactory. Carbonate of soda should be avoided in +connection with sodium silicate as the property of efflorescing on the +surface of the finished cake after a short time will prove detrimental. +To assure successful gluing up it is advisable to experiment upon a +small scale to determine the exact extent to which the filling solution +should be diluted. Various proportions of water are added to a certain +quantity of the filled soap. After the soap has been filled in a small +receptacle a sample is taken and rubbed between the fingers. If the +freshly exposed surface is smooth and glossy, the filling solution is +weak enough, if rough it is too strong. It is of course understood that +the temperature must be correct, 140 degs. to 150 degs. F., or the soap +will be rough. By this means the operator can readily judge the correct +strength of his filling solution. When properly carried out a perfectly +satisfactory soap is obtained. + + +CURD SOAP. + +The object of a soap which is finished "curd" or grained, is to obtain a +harder piece of goods from low titer fat or to increase the percentage +of fatty acids in the finished soap. This is still another method of +producing a cheap grade of soap as by its adoption the cheaper oils and +fats may be used to obtain a firm piece of soap. + +A typical charge for curd soap is: + + Red oil 63 parts + Tallow 10 " + Rosin 27 " + +Cotton seed foots may be employed in place of red oil and a tallow of +too high titer is not suitable for this kind of soap. + +The red oil and tallow are first saponified with 15 degs. B. lye, boiler +pressure 80-90 pounds, 18 degs. B. lye for lower steam pressure, and two +washings given to extract the glycerine. The rosin is added at the +strengthening change and at the finish the soap is "pitched," that is to +say, the soap is settled over night only. The next day the lyes are +drawn off and a portion of the nigre pumped to another kettle which +prevents later streaking of the soap. The soap is then boiled with 18 +degs. B. lye as with another strengthening change under closed steam. +Salt brine or "pickle," 15 degs. B. is then added and the mass boiled +with closed steam until the brine reaches a density of 18 degs. B. and +the kettle pumped the next day. A soap of this type requires either hand +or power crutching to assure homogeneity and prevention of streaks. To +obviate any air spaces it is advisable to place over the top of the +frame a tightly-fitted board which is heavily weighted down. This soap +is also pressed without any milling. + + +COLD MADE TOILET SOAPS. + +Comparatively little toilet soap is made by the cold or semi-boiled +processes. While these are the simplest methods of manufacturing soaps +the drawbacks of using them are numerous and only in a few cases are +they very extensively employed. To make a toilet soap by the cold +process a combination of good grade tallow and cocoanut oil is required. +It requires 50 per cent. by weight of 36 degs. B. lye to saponify a +given weight of tallow and 50 per cent. of 38 degs. B. lye for cocoanut +oil. The lyes are used full strength or may be reduced slightly with +water and the method of procedure is the same as already given in the +general directions for cold made soaps. + +Cold made soaps are readily filled with sodium silicate which is added +at the same time the stock is put into the crutcher. In adding the +silicate it is necessary to add additional lye to that required for +saponifying the fats, about 20 per cent. of 36 degs. B. lye is the +proper amount. There is of course a certain amount of shrinking due to +the addition of this filler and the finished cake is exceedingly hard, +yet the author has seen a good looking cake of cheap soap made from as +high a proportion as 420 parts of tallow to 600 parts of silicate. + +Cold made soaps are usually pressed without milling, although it is +readily feasible to mill a cold made soap provided it is not a filled +soap such as has just been described. + + +PERFUMING AND COLORING TOILET SOAPS. + +Equally important as the soap itself or even to a greater extent is the +perfume of a toilet soap. A prominent manufacturer recently made the +statement, which is often the truth, that it makes no difference to the +public what kind of soap you give them, as long as you put plenty of +odor into it. The perfuming of soaps is an art in itself and a subject +to be treated by one versed in this particular branch. We can only take +into account the importance of the perfume as related to toilet soap +not only, but the necessity of adding a certain proportion of the +cheaper products of odoriferous nature to laundry soap to cover and +disguise the odor of even this type of soap. + +The price of a cake of toilet soap to a great extent depends upon the +perfume, and the manufacturer should aim to give the best possible +perfume for a certain price. He should not allow his personal likes or +dislikes to enter into the judgment of whether an odor is good or not, +but submit it to a number of persons to obtain the concensus of opinion. +In giving or selling a piece of soap to the consumer, it is second +nature for him to smell it, and in the great majority of cases his +opinion is formed not from any quality the soap itself may have during +use, but from the odor. This only emphasizes the fact that the perfume +must be pleasing, not to one person, but to the majority, and many +brands owe their popularity to nothing more than the enticing perfume. + +Perfuming of soap is closely allied to the soap making industry, but as +stated a branch in itself. It is, therefore, not our purpose to give +numerous formulae of how to perfume a soap, but rather to advise to go +for information to some one who thoroughly understands the +characteristics of the numerous essential oils and synthetics and give +positive information for the particular odor desired. Under no +circumstances is it advisable to purchase a perfume already compounded, +but since all perfumes are a blend of several or many essential oils and +synthetics, it is a more positive assurance of obtaining what is +desired, by purchasing the straight oils and blending or mixing them as +one desires. + +The perfume is added to a milled soap just before the milling process in +the proper proportion per hundred pounds of soap. In cold made or +unmilled soaps it is added in the crutcher while the soap is still hot. +By this method, of course, a proportion of the perfume is lost due to +its being more or less volatile. + + +COLORING SOAP. + +While much toilet soap is white or natural in color, many soaps are also +artificially colored. The soap colors used for this purpose are mostly +aniline dyestuffs. The price of these dyestuffs is no criterion as to +their quality, as the price is usually regulated by the addition of some +inert, water soluble substance like common salt or sugar. + +The main properties that a dyestuff suitable for producing a colored +soap should have are fastness to light and to alkali. They should +further be of such a type that the color does not come off and stain a +wash cloth or the hands when the soap is used and should be soluble in +water. Under no circumstances is it advisable to add these in such a +quantity that the lather produced in the soap is colored. It is +customary to first dissolve the dye in hot water as a standardized +solution. This can then be measured out in a graduate and added to the +soap the same time as the perfume is put in. About one part of color to +fifty parts of water is the proper proportion to obtain a perfect +solution, though this is by no means fixed. In making up a solution thus +it is an improvement to add to the same about one-half of one per cent. +of an alkali either as the hydroxide or carbonate. Then, if there is any +possibility of change of color due to alkalinity of the soap, it will +exhibit itself before the color is added. + +A particularly difficult shade to obtain is a purple, as there is up to +the present time no purplish aniline color known which is fast to light. +Very good results in soap may be obtained by mixing a fast blue, as +ultramarine or cobalt blue, with a red as rhodamine or eosine. + +Inasmuch as the colors for soap have been carefully tested by most of +the dyestuff manufacturers, and their information, usually reliable, is +open to any one desiring to know about a color for soap, it is better to +depend upon their experience with colors after having satisfied one's +self that a color is what it is represented for a particular shade, than +to experiment with the numerous colors one's self. + + +MEDICINAL SOAPS. + +Soap is often used for the conveyance of various medicants, antiseptics +or other material presumably beneficial for treatment of skin diseases. +While soap is an ideal medium for the carrying of such materials, it is +an unfortunate condition that when incorporated with the soap, all but a +very few of the numerous substances thus employed lose their medicinal +properties and effectiveness for curing skin disorders, as well as any +antiseptic value the substance may have. Soap is of such a nature +chemically that many of the substances used for skin troubles are either +entirely decomposed or altered to such an extent so as to impair their +therapeutic value. Thus many of the claims made for various medicated +soaps fall flat, and really have no more antiseptic or therapeutic merit +than ordinary soap which in itself has certain germicidal and cleaning +value. + +In medicating a soap the material used for this purpose is usually added +at the mill. A tallow and cocoanut oil base is best adapted for a soap +of this type. The public have been educated more or less to the use of +colored soap to accentuate its medicinal value, and green is undoubtedly +the most popular shade. This inference, however, is by no means true for +all soaps of this character. Possibly the best method of arranging +these soaps is briefly to outline some medicinal soaps. + + +SULPHUR SOAPS. + +The best known sulphur soaps contain anywhere from one to 20 per cent. +of flowers of sulphur. Other soaps contain either organic or inorganic +sulphur compounds. + + +TAR SOAP. + +The tar used in the manufacturing of tar soap is obtained by the +destructive distillation of wood, the pine tar being the most +extensively employed. While the different wood tars contain numerous +aromatic compounds, such as phenols, phenyl oxides, terpenes and organic +acids, these are present in such a slight proportion so as to render +their effectiveness practically useless. It has, therefore, been tried +to use these various compounds contained in the tar themselves to make +tar soap really effective, yet tar is so cheap a substance that it is +usually the substance used for medicating a tar soap. About 10 per cent. +of tar is usually added to the soap with 2 ounces of lamp black per +hundred pounds of soap. + + +SOAPS CONTAINING PHENOLS. + +Phenol (Carbolic Acid) is most extensively used in soaps of this kind, +which are called carbolic soaps. Carbolic soaps are generally colored +green and contain from 1 to 5 per cent. phenol crystals. + +The cresols are also extensively used for making soaps named carbolic. +These substances impart more odor to the soap and really have more +disinfecting powers than phenol when incorporated with soap. + +Other soaps, containing the phenol group, which are well known are +resorcinol soap, salol soap, thymol soap, naphthol soap, etc. From one +to five per cent of the compound after which the soap is named is +usually incorporated with the soap. + + +PEROXIDE SOAP. + +Hydrogen peroxide in itself is an excellent disinfectant. It loses all +its medicinal value, however, when added to the soap. To overcome this +objection various metallic peroxides are added to the soap, as sodium +peroxide, zinc peroxide and barium peroxide. These generate hydrogen +peroxide by the addition of water. Sodium perborate is also used in +peroxide soaps, as this substance is decomposed by water into hydrogen +peroxide and sodium metaborate. + + +MERCURY SOAPS. + +Mercuric chloride (corrosive sublimate) is most extensively used for the +production of mercury soaps. Because of its extremely poisonous +properties care should be taken in using it. Since it really eventually +loses any antiseptic value in the soap through forming an insoluble +mercury soap it might better be omitted entirely. + + +LESS IMPORTANT MEDICINAL SOAPS. + +While the above mentioned soaps are probably the best known medicated +soaps, there are numerous other soaps which may be classed under these +kinds of soaps. Thus we have cold cream soap, which can be made by +adding Russian Mineral Oil, 1 to 5 per cent., to the soap; witch hazel +soap, made by the addition of extract of witch hazel; iodine soap, made +by adding iodine or iodoform; formaldehyde soap, made by adding +formaldehyde; tannin soaps, made by adding tannin. In fact, there have +been incorporated in soap so great a number of substances that the list +might be greatly enlarged. + +Medicated soaps are not only used in solid form, but in powder, paste +and liquid soap as well. The only difference in a soap like those just +referred to is that the medicant is incorporated with these forms of +soaps as convenience directs. + + +CASTILE SOAP. + +A pure castile soap should be made from olive oil. This, however, is not +always the case, as a number of oils as well as tallow are used to +adulterate this oil to cheapen it, and there are even some soaps called +castile which contain no olive oil at all. Most of the pure castile soap +used in this country is imported, as it is a difficult matter for the +American manufacturer to compete with the pure imported castile soap, +since both labor and oil itself are so much cheaper in the vicinities of +Europe where this oil is produced, that this advantage is more than +compensated by the carrying and custom charges by importing the castile +soap. + +Castile soap may be made either by the full boiled or cold process. +There are numerous grades of olive oil, and those used for soap making +are denatured to lower the duty charges. Olive oil makes a hard white +soap, usually sold in bars, and olive oil foots a green soap, due to the +coloring matter contained in this oil. + +To make a boiled castile soap, a composition of 10 per cent. Cochin +cocoanut oil and 90 per cent. olive oil may be used. To cheapen this, +peanut oil (Arachis oil) may entirely replace the olive oil, or about 20 +per cent. of corn or soya bean oil may be added. The oils are saponified +as usual in making a settled soap and to prevent rancidity the soap is +boiled near the finish for some time in the closed state with +sufficient excess of alkali to give it a sharp taste, then grained with +lye, the lye drawn off, closed with water and then grained with salt. +This process is repeated until the desired strength is reached. The last +graining should not be too great, and on the last change the soap should +not be thinned out, as it will contain too great a quantity of water +when slabbed. + +In making a cold castile soap the usual method is pursued as already +directed under cold made soap. When the soap is taken from the crutcher +it is advisable, however, to keep the soap in the frame well covered to +assure complete saponification. Some manufacturers use very small frames +which are placed into compartments, well insulated to retain heat. +Several formulae for cold made castile soaps, follow. It may be noted +that some of these contain practically no olive oil. + + I + + Olive oil 2030 + Palm kernel 674 + Soda lye, 35 per cent. B. 1506 + + II + + Olive oil 2030 + Cochin cocoanut oil 674 + Soda lye, 36 per cent. B. 1523 + Sodium Silicate 82 + + III + + Palm kernel oil 1578 + Tallow 940 + Olive oil 7 + Sodium silicate, 20 per cent. 190 + Soda lye, 36 per cent. B. 1507 + + IV + + Olive oil (yellow) 1000 + Soda lye, 37 per cent. B. 500 + + V + + Olive oil 90 + or + Palm kernel } 10 + Cochin or cocoanut oil } 10 + Lye, 37 per cent. B. 51 + +If any of the soaps containing a high proportion of cocoanut oil are +boiled the soap will float. It is therefore necessary to keep the +temperature as low as possible. + + +ESCHWEGER SOAP (BLUE MOTTLED). + +Eschweger soap is a colored mottled or marbled soap made to a very +slight extent in this country. Inasmuch as it has been introduced to the +export trade, it is made for this purpose by some manufacturers. A high +percentage of cocoanut oil is usually used together with tallow and +grease. About one-third of each is a typical formula. In a soap of this +character the fact that cocoanut oil soap takes up a large quantity of +water and salts of various kinds and is difficult to salt out is made +use of. The tallow and grease are first saponified as usual, then the +cocoanut oil is pumped and saponified. When the saponification is nearly +completed either silicate or carbonate of soda or common salt are added +to make the soap "short" so as to form the mottle. The finishing of a +soap of this type can only be gained by practice and it is rather +difficult to explain the exact appearance of the kettle at this stage. +The surface of the soap should be bright and lustrous with the steam +escaping in numerous places in rose-like formation. A sample on the +trowel should have a slight sharpness to the tongue and be plastic. When +the soap slides from the trowel it should break short. When the soap has +reached this stage the desired coloring matter, usually ultramarine, is +added to the soap either in the kettle or crutcher and the soap framed. +The yield is 200-215 pounds per hundred pounds of stock. + +Several modifications of this general method for Eschweger soap are used +by adopting the half boiled or cold process. + + +TRANSPARENT SOAP. + +Transparent soap is really not a most desirable soap for toilet +purposes, as it contains an excess of free alkali. It has, nevertheless, +met with public approval because of the fact it is novel in being +transparent. Except for this fact very little merit can be claimed for a +soap of this kind. + +The transparency of soap is generally due to the presence of alcohol, +sugar or glycerine in the soap when it is made. It is very essential in +a soap of this character, where lightness and clearness of color are +desired, that the material for making the soap be carefully selected as +to color and purity. The perfumes also play an important part in the +color of the soap and many of the tinctures, balsams and infusions used +in perfuming soap may eventually cause trouble by spotting. If the soap +is artificially colored, which is almost always the case, the dyestuffs +used for this purpose should have careful attention and only those +should be used which are known to resist the action of alkalis. Where +rosin is used this product must be of the better grade. Distilled water +is always preferable for use in transparent soap. The government permits +the use of a specially denatured alcohol. This alcohol is not taxed and +consists of grain (ethyl) alcohol denatured with 5 per cent. wood +(methyl) alcohol. Some soapmakers prefer to use a more expensive refined +methyl alcohol, but outside of adding to the cost of the soap, there is +no particular advantage. The glycerine should be chemically pure. As to +the oils and fats these should be low in acid and of good color. Under +no circumstances should the crutcher or kettle in which the soap is made +be rusty or unclean in any way. For a light soap enameled utensils are +to be preferred. + +To obtain transparency in soap the following general methods may be +given. + +1. Where the transparency is due to sugar. + +2. Where alcohol and glycerine produce transparency. + +3. Where (1) or (2) is supplemented by the use of castor oil. + +4. Where transparency depends upon the percentage of fatty acid in a +soap and the number of times the soap is milled. + +Under the first method at least 25 per cent. of the charge should be +cocoanut oil, the other constituent being tallow or any fat or oil +capable of giving a sufficiently hard soap. The soap is boiled and +finished as usual, then run to the crutcher to be mixed with a strong +cane sugar solution, containing 10-20 per cent. sugar of the weight of +the soap. The sugar is dissolved in its own weight of water and the +solution heated to 175 degs. F. before being very slowly added to the +soap. As the water evaporates, soaps of this type show spots due to the +sugar thus being thrown out of solution. + +Transparent soap made under the second method may be saponified as usual +and consist of any good toilet base. The soap is run to the crutcher and +mixed with 95 per cent. alcohol in the proportion of one part alcohol to +two parts of fatty acid contained in the soap together with glycerine in +the same proportion. + +By the third method castor oil alone may be used to make the soap or +added to any of the above bases up to 33-1/3 per cent. of the charge. If +castor oil only is used, but 2 per cent. or 3 per cent. of sugar is +required. + +In the last method a combination of 80 per cent. tallow, very low in +free acid, 20 per cent. cocoanut oil and 5 per cent. W. W. rosin is a +suitable charge. The saponification and finishing is carried out as with +a full boiled soap. The soap is then placed into a jacketed vessel, +provided with dry-steam coils, by which the excess water is evaporated +from the soap until it contains 73 per cent. fatty acids. When the thick +mass reaches this stage it is framed and when cool is suitable for +obtaining a semi transparency which now depends upon the number of times +the soap is milled, it being, of course, inferred that no solid matter +of any sort be added to the soap. + + +COLD MADE TRANSPARENT SOAP. + +While transparent soaps may be made by the above general methods they +are usually made by the semi-boiled or cold process. By this process a +more satisfactory soap is obtained and it is more simple to carry out. A +detailed description of this method is best and most easily given by +using a typical formula. + + Charge: + + Tallow 193-1/2 lbs. + Cochin Cocoanut Oil 169-1/2 " + Castor Oil 89-1/2 " + Soda Ash 7-3/4 " + Soda Lye, 36 degs. B. 256 " + Sugar (Cane) 198 " + Alcohol 126 " + Water (Distilled) 80 " + +To proceed, first place into a crutcher or jacketed kettle the oils and +fat and heat to 140 degs. F. Then add the soda ash dissolved in about 30 +pounds of the water, after which the lye is added and the mass stirred +until a finger or stick run over the surface leaves an imprint. Where +the soap has reached this stage, it is well covered and allowed to stand +about two hours or until it bulges in the center, after which the rest +of the water which should contain no lime or other mineral substance and +which is preferably distilled water, is added. The sugar is then slowly +shoveled in while the mass is stirring and finally the alcohol is poured +in. The heat is then increased to 160 degs. F. by dry steam and the soap +crutched until dissolved. Under no circumstances should any soap be +allowed to remain above the surface of the mass on the sides of the +mixer. This crutching operation consumes about one hour, and when +finished the soap should stand in the vessel about half an hour when a +small sample is taken out to cool. This sample should be clear and show +an excess of alkali. If it is not clear more alcohol is added, if not of +sufficient strength more lye put in until the desired condition is +reached. The perfume and color are now added. + +The soap is then framed and allowed to set after which it is cut, +allowed to dry slightly and then pressed. To obtain a polished cake +transparent soaps are often planed before pressing and after pressing +polished with a soft cloth, dampened with alcohol. Instead of framing +this soap, it is sometimes "tubed," that is to say, the soap from the +crutcher is run into specially constructed tubes of a shape near that of +the desired cake and allowed to cool, after which it is cut and pressed. +All scraps are returned to the crutcher, but in so doing the soap is +slightly darkened in color. It is advisable to expose a finished cake of +transparent soap to the air for some time as by so doing it becomes +clearer. + +Other formulae for cold made transparent soaps made as just outlined +follow: + + I. + Bleached Tallow 134 lbs. + Cochin Cocoanut Oil 88 " + Castor Oil 20 " + W. W. Rosin 7 " + Cane Sugar 64 " + Water 32 " + Glycerine 34 " + Soda Lye, 38 degs. B. 135 " + Alcohol 16 gal. + + II. + Tallow 211 lbs. + Cochin Cocoanut Oil 185 " + Castor Oil 97-1/2 " + Soda Ash 8-1/2 " + Water 106 " + Soda Lye, 38 degs. B. 279 " + Sugar 216 " + Alcohol 137 " + + III. + Castor Oil 60 lbs. + Cochin Cocoanut Oil 195 " + Tallow 120 " + Alcohol 115 " + Sugar 90 " + Water 53 " + Glycerine 53 " + Soda Lye, 38 degs. B. 205-1/2 " + + IV. + Tallow 100 lbs. + Cochin Cocoanut Oil 100 " + Castor Oil 60 " + Glycerine 20 " + Rosin, W. W. 20 " + Sugar 40 " + Water 50 " + Soda Lye, 36 degs. B. 164 " + Alcohol 8 gal. + + V. + Tallow 174 lbs. + Cocoanut Oil 114 " + Soda Lye, 38 degs. B. 170 " + Sugar 80 " + Water 72 " + Alcohol 16 gal. + +Rosin may be added in this formula up to 20 per cent. of fats used and +the tallow cut down correspondingly. + + +SHAVING SOAPS. + +The requirements of a shaving soap are somewhat different than those of +other soaps. To be a good shaving soap the lather produced therefrom +must be heavy, creamy, but not gummy, and remain moist when formed on +the face. The soap itself should be of a soft consistency so as to +readily adhere to the face when used in stick form. It should +furthermore be neutral or nearly so to prevent the alkali from smarting +during shaving. + +Shaving soap is made in the form of a stick, and a tablet for use in the +shaving mug. Some shavers prefer to have the soap as a powder or cream, +which are claimed to be more convenient methods of shaving. While a +liquid shaving soap is not as well known because it has not yet become +popular, some soap for shaving is made in this form. + +Formerly shaving soap was extensively made from a charge of about 80 +parts tallow and 20 parts cocoanut oil as a boiled settled soap, but +either making the strengthening change with potash lye or using potash +lye in saponifying the stock and graining with salt. Soaps for shaving +made in this manner are very unsatisfactory, as they do not produce a +sufficiently thick or lasting lather and discolor very materially upon +ageing. Potassium stearate forms an ideal lather for shaving, but +readily hardens and hence needs some of the softer oils, or glycerine +incorporated with it to form a satisfactory soap for shaving. + +The selection of materials for making a shaving soap is important. The +tallow used should be white and of high titer. Cochin cocoanut oil is to +be preferred to the other kinds, and the alkalis should be the best for +technical use that can be purchased--76 per cent. caustic soda and 88-92 +per cent. caustic potash are suitable. By the use of stearic acid it is +a simple matter to reach the neutral point which can be carefully +approximated. + +The following are shaving soap formulae which have been found to give +good satisfaction: + + I. lbs. + Tallow 360 + Stearic acid 40 + Soda lye, 41° B. 147 + Potash lye, 34° B. 87 + Water 32 + Gum tragacanth 1 + + II. lbs. + Tallow 282 + Cocoanut oil 60 + Stearic acid 50 + Bayberry wax 18 + Soda lye, 41° B. 147 + Potash lye, 34° B. 90 + Water 32 + + III. lbs. + Tallow 400 + Cocoanut oil 176 + Stearic acid 415 + Caustic soda, 40° B. 182 + Caustic potash, 38° B. 108 + +To proceed, first run into the crutcher the tallow, cocoanut oil and +bayberry wax when used, and bring the temperature of the mass up to +140°-160° F. by dry steam. Then add the caustic soda lye and keep on +heat with occasional mixing until it is all taken up. When this stage is +reached gradually add all but about 5 per cent. of the potash lye, and +complete the saponification. This point having been reached, the heat is +turned off; the crutcher is run and the stearic acid, previously melted +by dry steam in a lead-lined or enameled vessel, is run in in a +continuous stream and the crutching continued for fifteen minutes to +half an hour. Samples are taken at this time, cooled and tested by +alcoholic phenolphthalein solution. If too alkaline more stearic acid is +added, if too acid more potash lye from that previously reserved. After +each addition of lye or stearic acid the mass is crutched from 10 to 15 +minutes longer, another sample is taken, cooled and again tested. When +the phenolphthalein shows a very light pink after several minutes, the +soap is practically neutral, although at this point one can better judge +by dissolving a sample in hot neutralized alcohol made by putting into +the alcohol a few drops of phenolphthalein, and then adding weak alkali +drop by drop from a burette until a slight pink, not yellow, tint is +obtained, and noting the color of the solution. The solution should show +a very light pink when the soap is properly neutralized. When this stage +is arrived at the gum tragacanth, previously softened in water, is +crutched in if it is to be added. The soap is then framed, stripped in +three or four days, dried and milled. + +The formulae as given are for shaving sticks, and do not readily press +unless thoroughly dried. A more satisfactory result is obtained by +adding at the mill 25 per cent. of white tallow base to obtain a +satisfactory mug soap. + + +SHAVING POWDER. + +Shaving powder differs from the soaps just described in being +pulverized, usually adding up to 5 per cent. starch to prevent caking. +Any of the above soaps, dried bone dry, with or without the addition of +tallow base make a satisfactory powder for shaving. + + +SHAVING CREAM. + +Shaving cream is now a very popular shaving medium due to the rapidity +and convenience with which one can shave by the use of this product. +Formerly shaving cream was made from the liquid oils like olive oil and +a soft fat like lard, together with cocoanut oil. Now, however, most of +the popular shaving creams are made from stearic acid and cocoanut oil, +as a far superior product is obtained by the use of these substances. By +using these a more satisfactory cream is obtained, and it is far more +convenient to make. The lather also produced therefrom is more suitable +for shaving, being thick, creamy and remaining moist. + +A few typical formulae for shaving creams of this type are as follows: + + I. lbs. + Cochin cocoanut oil 26 + Stearic acid 165 + Caustic potash lye, 50° B. 69 + Glycerine C. P. 76 + Water 38 + + II. lbs. + Cochin cocoanut oil 18 + Stearic acid 73 + Caustic potash lye, 39° B. 54 + Glycerine 33 + Water 27 + + III. lbs. + Cochin cocoanut oil 18 + Stearic acid 73 + Caustic potash lye, 39° B. 54 + Glycerine 20 + Water 40 + + and lbs. + + Stearic acid 60 + Glycerine C. P. 85 + Water 165 + Sodium carbonate 50 + Borax 1 + +To make a shaving cream by Formula I or II, the cocoanut oil and +glycerine are first put into a suitable mixing apparatus or crutcher, +and heated to 120° F. A part or all the potash lye is then added and the +cocoanut oil saponified. The rest of the potash lye and the water are +then added, and with the mixer running the stearic acid, previously +melted in a lead-lined or enameled vessel, is then poured in in a stream +and the mass stirred until smooth, care being exercised not to aerate it +too much. The cream is then tested for alkalinity, the best method being +by that described under shaving soap, in which the sample is dissolved +in alcohol. Because of the large quantity of water present, +phenolphthalein is unsatisfactory, as dissociation of the soap may show +a pink indication in spite of the fact the mass is on the acid side. For +a quick method of testing the bite on the tongue is a satisfactory +criterion. If a cooled sample bites the tongue more stearic acid is +added until there is a 3% excess of this. When the proper neutralization +has taken place the cream is perfumed and framed in a special frame, or +it may be allowed to cool in the mixer and perfumed the next day. When +cool the cream is strained, or put through an ointment mill, after which +it is ready to fill into tubes. + +The procedure for the first part of Formula III is the same as that just +given. The second part of the formula is made the same as a vanishing +cream for toilet purposes. To make this, first melt the stearic acid as +already directed. Dissolve the sodium carbonate and borax in water and +when dissolved add the glycerine and stir. Then heat this solution to +about 100°-120° F. and while stirring in a suitable mixing machine into +which this solution has been poured after being heated, or better still +in which it has been heated by dry steam, add the stearic acid. Continue +mixing until smooth and then allow to cool, or run into frames to cool. + +When the shaving cream and vanishing cream are both cool, they are mixed +in the proportion of one of the former to two of the latter. It is +claimed that in thus making a shaving cream a smoother product is +obtained, although it may be said that the vanishing cream is merely a +soft soap and the ultimate result is the same as though the various +ingredients were added in one operation, rather than making two separate +products and then mixing them, thereby considerably increasing the cost +of manufacture. + + +PUMICE OR SAND SOAPS. + +Pumice and sand are at times added to soap to aid in the removal of dirt +in cleansing the hands. In some cases these soaps are made in the form +of a cake, in others they are sold in cans in the form of a paste. + +A hand paste is usually made by merely dissolving ordinary tallow base +in two or three times its weight of hot water and mixing in the desired +quantity of pumice or sand and in some instances adding a little +glycerine to keep it soft or a solvent of some kind for grease. It may +also be made by directly incorporating any of these in a potash soap. + +A cold made or semi-boiled cocoanut or palm kernel oil soap is the base +used to add the pumice or sand to in making a cake soap of this sort. +The following formulae serve as a guide for these soaps. + + I. + + Palm Kernel or Ceylon Cocoanut Oil 705 lbs. + Pumice (Powdered) 281 " + Soda Lye, 38° B. 378 " + + II. + + Cocoanut Oil 100 " + Soda Lye, 38° B. 55 " + Water 6 " + Silver Sand (fine) 60 " + +To proceed place the oil in a crutcher and heat to 140° F. Sift in the +pumice and mix thoroughly. The lye is then added which causes a curdling +of the grain. The stirring is continued until the grain closes and the +soap is smooth, after which the desired perfume is added and the soap +dropped into a frame and crutched by hand. When the soap is set, it is +slabbed, cut into cakes, dried slightly and pressed. + + +LIQUID SOAPS. + +Liquid soaps are merely solutions of a potash soap, usually cocoanut oil +soap, although corn oil is used to make a cheap soap. One of the +difficulties encountered in liquid soap is to keep it clear. At a low +temperature a sediment is often formed, but this can be overcome by the +use of sugar and filtering the soap through a filter press at a low +temperature. In order to prevent the soap from freezing, it is necessary +to lower the freezing point by the addition of glycerine or alcohol. + +To make liquid soap by any of the formulae given below, the oil is first +run into a jacketed kettle with a stirring device, and heated to about +120° F. The potash lye is then added and the oil saponified. When the +saponification takes place, especially when cocoanut oil is used, the +mass swells rapidly and may foam over the sides of the kettle unless +water is used to check this, or a kettle of about four to five times the +capacity of the total charge of soap is used. When the saponification +has occurred, the sugar, borax and glycerine are added, the water run in +and the mixture stirred until the soap is thoroughly dissolved. Heat +aids materially in dissolving the soap. The soap is then allowed to cool +and if color or perfume is to be added this is stirred in, after which +the soap is cooled and filtered or else run directly into barrels. + +Tallow is not suitable for making a clear liquid soap since it is too +high in stearine which when formed into the stearate makes an opaque +solution. The formulae herewith given have been found to give good +practical results. + + I. lbs. + Cocoanut oil 130 + Caustic potash lye, 28° B. 135 + Sugar 72 + Borax 2 + Water 267 + + II. lbs. + Corn oil 130 + Caustic potash lye, 26° B. 135 + Sugar 72 + Borax 2 + Water 267 + + III. lbs. + Cocoanut oil 100 + Caustic potash lye, 28° B. 102 + Glycerine 100 + Sugar 70 + Water 833 + +Formulae I and II contain about 20 per cent. fatty acids. It is +possible, of course, to either increase or decrease the percentage of +fatty acid by varying the amount of water. The water used in making +liquid soaps, of course, should be soft, for hard water forms insoluble +soaps which precipitate and cause a sediment. + + +USE OF HARDENED OILS IN TOILET SOAPS. + +While the introduction of the hydrogenation of oils is a decided advance +in the production of suitable cheaper oils for soap making, +comparatively little hardened oil is employed for soap making in America +up to the present time. In Europe, however, considerable advance has +been made by the use of such oils for manufacturing soap therefrom and a +number of plants turn out large quantities of hydrogenated oils for soap +making as well as for edible purposes. Recently a company has been +formed in this country for hardening oils and it is very probable that +the future will see this material extensively used in our own country, +as these appear to be the one present hope of the soap manufacturer as a +check on the ever increasing cost of fats and oils now used in making +soap. + +It is an unfortunate condition that hydrogenated oils produced abroad +are sold under names which give absolutely no indication as to the oil +which has been hardened. The softer and cheaper oils like fish oil, +linseed oil, cottonseed oil, etc., are generally hardened for soap +manufacture to different degrees of hardness. While it is impossible to +definitely state just what products as Candelite, Talgol, Krutolin or +several other coined names of hardened oils are, various investigators +have experimented with them as to their adaptability for producing +toilet soaps and found that suitable toilet soaps may be made from them. +While many objections were at first met with concerning soaps made from +these products, as to their unsatisfactory saponification, the poor +lathering quality of the soaps and their odor and consequent difficulty +in perfuming, the results of most investigators along these lines +indicate that these in many cases were due to prejudice against or +unfamiliarity with handling oils of this type for soap making. + +In manufacturing soap from hardened oils it is usually necessary to +incorporate with the charge lard, tallow, tallow oil or some other soft +oil of this nature. Satisfactory bases for toilet soaps, made as boiled +settled soap by the use of Talgol (undoubtedly hardened fish oil), are +said to be made by the formulae[10] below. + + I. + + Tallow 45 parts + Talgol 40 " + Cocoanut Oil 15 " + + II. + + Cocoanut Oil (Ceylon) 6 " + Tallow 12 " + Talgol, Extra 12 " + +The method of boiling a soap of this type does not differ materially +from that of making settled tallow soap base. The soap itself has a +different odor than a straight tallow base, but is said to make a very +satisfactory soap for milling and to be of good appearance. + +Satisfactory transparent soaps are made from the hardened oil Candelite, +which replaces the tallow in transparent soap formulae such as have +already been given in the section under "Transparent Soaps." The method +of manufacturing a soap by the use of this product varies in no way from +the usual method employed for making these soaps. + +Since hydrogenated oils are high in stearine, their use in shaving soaps +is a decided advantage. It has previously been pointed out that +potassium stearate forms an ideal lather for shaving, and in the +hydrogenating process the olein is converted to stearine. Thus a +hardened oil is advantageous in a shaving soap. As an example of a cold +made soap for shaving the following may be taken.[11] + + Talgol Extra 50 lbs. + Cocoanut Oil 10 " + Lard 10 " + Soda Lye, 38° B. 20 " + Potash Lye, 37° B. 21 " + +This soap may be made in a crutcher by the method generally used in +making soap by the cold process. + + +TEXTILE SOAPS. + +Soap is a very important product to every branch of the textile +industry. For woolen fabrics it is used for scouring, fulling and +throwing the wool; in the silk industry it is necessary for degumming +the raw silk, as well as for dyeing; in the cotton mills it is used to +finish cotton cloth and to some extent in bleaching; it is, furthermore, +employed in a number of ways in the manufacture of linen. Large +quantities of soap are thus consumed in an industry of so great an +extent and the requirements necessitate different soaps for the +different operations. We will, therefore, consider these in detail. + + +SCOURING AND FULLING SOAPS FOR WOOL. + +The soaps used to scour wool and for fulling the woven cloth are usually +made as cheaply as possible. They are, however, generally pure soaps, as +filling material such as sodium silicate does not readily rinse out of +the wool and if used at all must be added very sparingly. Both cold made +and boiled settled soaps are made for this purpose. The soap is +generally sold in barrels, hence is run directly to these from the +crutcher or soap kettle. As cold made soaps the following serve for wool +scouring or fulling. + + I. + + Palm Oil 200 lbs. + Bone Grease 460 " + Soda Lye, 36° B. 357 " + Water 113 " + Soda Ash 50 " + Citronella 2 " + + II. + + Palm Oil (Calabar, unbleached) 155 " + House Grease 360 " + Soda Lye, 36° B. 324 " + Water 268 " + Sodium Silicate 83 " + + III. + + House Grease 185 " + Palm Oil (unbleached) 309 " + Soda Lye, 36° B. 309 " + Water 391 " + Soda Ash 70 " + Sodium Silicate 60 " + Corn Starch 10 " + +These soaps are made in a crutcher by the usual process for cold-made +soaps, crutched until smooth, dropped into a barrel and crutched by hand +the next day or just before cooling. + +As a settled soap for these operations the following charge is typical: + + Palm Oil 34 parts + Cottonseed foots or its equivalent in fatty acids 33 " + Rosin 10 " + House Grease 23 " + +The method of boiling such a soap is the same as for any settled soap up +to the strengthening change. When this stage is reached, sufficient lye +is added to strengthen the kettle strongly. It is then boiled down with +closed steam on salt brine or "pickle" until a sample of the lye taken +from the bottom stands at 16°-22° B. The soap is then run into barrels +and after standing therein for a day is hand crutched until cool to +prevent streaking of the soap. + +Besides a soap of this type a settled tallow chip soap is used. + + +WOOL THROWER'S SOAP. + +Soaps for wool throwing are sometimes made from olive oil foots but +these are often objected to because of the sulphur-like odor conveyed to +the cloth due to the method by which this oil is extracted with carbon +disulphide. A potash soap hardened somewhat with soda is also used. As a +formula for a suitable soap of this type this may be given. + + Olive Oil Foots 12 parts + Corn Oil 46 " + House Grease 20 " + Soda Lye, 36° B. 3 " + Potassium Carbonate (dry) 5-3/4 " + Potassium Hydrate (solid) 23 " + +This soap is made as a "run" soap by the general directions already +given for a soap thus made. The kettle is boiled with open and closed +steam, adding water very slowly and aiming to obtain a 220-225 per cent. +yield or fatty acid content of the finished soap of 46 per cent. When +the soap is finished a sample cooled on a plate of glass should be +neither slippery or short, but should string slightly. The finished soap +is run directly into barrels. + +A soap for wool throwing by the semi-boiled process may be made from +olive oil foots in a crutcher thus: + + Olive Oil Foots 600 lbs. + Potash Lye, 20° B. 660 " + +The oil is heated to 180° F., the lye added and the mass stirred until +it bunches, when it is dropped into barrels. + + +WORSTED FINISHING SOAPS. + +For the finishing of worsted cloth soaps high in cocoanut oil or palm +kernel oil are preferred. These soaps are finished very neutral, being +made as settled soaps, but given an extra wash change after +strengthening strongly. They are then finished as usual and run into +barrels. If framed too hot, the high percentage of cocoanut oil causes +mottling, which is prevented by crutching by hand until the temperature +of the soap is 140°-145° F. Some typical charges, all of which are +saponified with soda lye, follow: + + I. + + Palm Kernel Oil 60 parts + Corn Oil 40 " + + II. + + Palm Kernel Oil 30 " + Red Oil (single pressed) 70 " + + III. + + Red Oil 33-1/3 " + Corn Oil 33-1/3 " + Cocoanut Oil or Palm Kernel Oil 33-1/3 " + + +SOAPS USED IN THE SILK INDUSTRY. + +Soap is used to a very large extent in silk mills, both for degumming +the raw silk and in silk dyeing. Raw silk consists of the true silk +fibre known as fibroin and a gummy coating, sericin, which dulls the +lustre of the silk unless removed. For this purpose a slightly alkaline +olive oil foots soap is best adapted, although palm oil and peanut oil +soaps are sometimes used, as well as soaps made from a combination of +house grease to the extent of 30 per cent., together with red oil or +straight olein soaps, both of which are artificially colored green. In +using house grease, if 30 per cent. is exceeded in combination with red +oil, the titer is raised to such an extent that the soap does not +readily rinse from the silk nor dissolve readily. They are also not +advisable because they impart a disagreeable odor to the silk. + +To make a soap for this purpose from olive oil foots it is made as a +settled soap, care being taken to thoroughly boil the mass on the +saponification change in the closed state to assure proper +saponification. The kettle is usually grained with lye and given a good +wash change to remove the excess strength. The change previous to the +finish should not be too heavy or too large a nigre results. The lighter +the grain is, the better the finished kettle is. A yield of 150 per +cent. is usually obtained. This soap is generally run to a frame, +slabbed upon cooling and packed directly into wooden cases. + +For silk dyeing the above soap is suitable, although any well-made soap +of good odor and not rancid is useable. While soap alone is often used +in the bath for silk dyeing, certain dyestuffs require the addition of +acetic or sulphuric acid, which sets free the fatty acids. If these be +of bad odor it is taken up by the silk and is difficult to remove. The +most generally used soaps are the just mentioned olive foots soap or a +soap made from a good grade red oil. + +Both kinds are extensively used. + + +SOAPS USED FOR COTTON GOODS. + +In the manufacture of cotton goods, as compared to the wool and silk +industries, very much less soap is used and it is only applied to the +finished fabric either to clean the cloth preparatory to dyeing or to +aid in dyeing with certain colors. It is also used in calico printing. +For cleansing the cloth ordinary chip soap is suitable although a more +alkaline soap finished as a curd soap is an advantage in that the free +alkali contained therein aids in removing the dirt and has no harmful +effect on the cotton. For dyeing cotton goods or to brighten certain +colors after dyeing an olive oil foots soap is most generally employed. +In calico printing soap is used to wash and clear the cloth after +printing. A soap for this purpose should be easily soluble in water and +contain no free alkali, rosin or filler. The best soaps for use in +calico printing are either an olive oil foots soap or an olein soap. + + +SULPHONATED OILS. + +While sulphonated oils are not used to any great extent in the +manufacture of soap, they are used very largely in the dyeing and +printing of turkey and alizarine reds on cotton as well as other colors. +Just what action these oils have is not known. Turkey red oil or +sulphonated castor oil is the best known sulphonated oil. + +The process of making these oils is simple. The equipment necessary is a +wooden tank or barrel of suitable capacity, approximately two and a half +times the amount of oil to be treated. There are furthermore required +other tanks or vessels to hold the solutions used such as caustic soda, +ammonia and acid. The tank to be used for the preparation of sulphonated +oil should be provided with a valve at the bottom of the tank and a +gauge to measure the quantity of liquid therein. + +The process is carried out as follows: + +Three hundred pounds of castor oil are placed in the tank and 80 pounds +at 66 deg. B. sulphuric acid are weighed out in another vessel. The acid +is run into the tank containing the oil in a very thin stream while the +oil is well stirred. At no time should the temperature exceed 40 deg. C. +This operation should consume at least an hour and stirring should be +continued half an hour longer to insure the thorough mixing of the oil +with the acid. The mass is then allowed to settle for 24 hours, after +which 40 gallons of water are added and the mixture stirred until it has +a uniform creamy color indicating no dark streaks. This mixing process +should be carefully carried out and when completed allowed to settle 36 +hours. At this point the mass will have separated into two layers, the +lower layer consisting of a water solution of acid and the upper layer +of oil. The former is run out through the valve located at the bottom of +the tank. Another wash may now be given or dispensed with as desired. In +this wash the addition of salt or sodium sulphate at the rate of 1-1/2 +pounds per gallon of water is advisable. A 24 deg. B. caustic soda +solution is prepared and added slowly to the acidified oil with constant +stirring. The mass first turns creamy, then becomes streaked, increasing +in streaks as the caustic solution is poured in, and finally becomes +clear and transparent. Water is now added to bring the volume to 75 +gallons. The oil is now milky in appearance, but the addition of a +little more soda solution restores the transparency. + +In some cases ammonia is used in addition to caustic soda in +neutralizing the oil. Three-fourths of the amount of caustic soda +required to complete the neutralization is first added and then the +neutralization is completed with a one to one liquid ammonia and water +solution. + +FOOTNOTES: + +[9] Seifensieder Ztg., 40, 47, 1266 (1913). + +[10] Seifensieder Ztg. (1913), p. 334 and 338. + " " (1912), p. 1229 and 1257. + +[11] Seifensieder Ztg. (1912), p. 954. + + + + +CHAPTER V + +Glycerine Recovery. + + +The recovery of glycerine is very closely allied with the soap-making +industry, because glycerine is the very valuable by-product obtained in +the saponification of oils and fats. No soap plant is, therefore, fully +equipped unless it has some method whereby the glycerine is recovered +and the importance of recovering this product cannot be too strongly +emphasized. + +It has already been pointed out that neutral fats or the glycerides are +a combination of fatty acid with glycerine. These are split apart in the +process of saponification. While by the term _saponification_ as used in +soap making it is inferred that this is the combination of caustic +alkalis with the fatty acids to form soap, this term is by no means +limited to this method of saponification, as there are various other +methods of saponifying a fat. The chemical definition of saponification +is the conversion of an ester, of which glycerides are merely a certain +type, into an alcohol and an acid or a salt of this acid. Thus, if we +use caustic alkali as our saponifying agent for a fat or oil, we obtain +the sodium or potassium salt of the higher fatty acids or soap and the +alcohol, glycerine. On the other hand, if we use a mineral acid as the +saponifying agent, we obtain the fatty acids themselves in addition to +glycerine. While the former is by far the most generally employed for +making soap, other processes consist in saponifying the fats by some +method other than caustic alkalis and then converting the fatty acids +into soap by either neutralizing them with sodium or potassium carbonate +or hydrate. + +It is important to again point out here that fats and oils develop free +fatty acid of themselves and that the development of this acid +represents a loss in glycerine. The selection of an oil or fat for soap +making should therefore to a large extent be judged as to its +adaptability by the free fatty acid content, as the higher this content +is, the greater is the loss in the glycerine eventually obtained. +Glycerine often represents the only profit to a soap manufacturer. It is +indeed necessary to determine the percentage of free fatty acid before +purchasing a lot of stock to be made into soap. + +In taking up the question of glycerine recovery we will consider the +various methods thus: + +1. Where the glycerine is obtained from spent lye by saponifying the +fats or oils with caustic alkali. + +2. Where the glycerine is obtained by saponifying the fats or oils by +some other method than the above, of which there are the following: + + (a) Twitchell process. + (b) Saponification by lime in autoclave. + (c) Saponification by acid. + (d) Saponification by water in autoclave. + (e) Fermentative (Enzymes). + (f) Krebitz process. + + +RECOVERY OF GLYCERINE FROM SPENT LYE. + +The spent lye obtained from the glycerine changes in making soap varies +greatly, the quality depending upon the stock saponified and the soap +maker's care in handling the operation. No two lyes run exactly alike as +to proportion of the various ingredients, although they are all similar +in containing the same substances either in solution or suspension. +Spent lye is a water solution of mainly glycerine, free alkali either as +caustic alkali or carbonate and salt, including sodium sulfate, but +furthermore contains some soap and albuminous matter either in solution +or suspension. Upon standing in the storage tank the greater part of +the soap usually separates when the lye cools. In order to assure the +greatest economical yield of glycerine by saponifying a fat with caustic +soda it is necessary to obtain a proportion of three parts of water to +every part of fat made into soap. Test runs have shown that this is the +proper proportion and that it is not economical to greatly exceed this +amount, and if a much less proportion is used the full yield of +glycerine is not obtained. + +The spent lyes contain varying amounts of glycerine, the first change +being richest in glycerine content, and this being reduced in the +subsequent changes. If the lyes always run high in glycerine it is an +indication that it is not all being obtained. The usual percentage is +from 0.5% to 5% or even more, although the average is somewhere around +2% to 3%. The lye as it comes from the kettle should not contain any +more than 0.5% to 0.6% of free alkali calculated as sodium carbonate, +Na_{2}CO_{3}. If the proportion is higher than this, it shows that the +saponification has been conducted with too high a proportion of alkali, +a condition which should be corrected in the kettle room. An excess of +free alkali does not interfere to any great extent with the successful +recovery of the glycerine, but is a waste of both alkali and the acid +used in neutralizing this. It is, therefore, more economical to run a +strong lye over fresh stock and neutralize the alkali thus, rather than +treating the lye for glycerine recovery. + +Before the spent lye can be run into the evaporator it is necessary to +remove the albuminous impurities and soap and to neutralize the excess +alkali to between exactly neutral and 0.02% alkalinity. The lye should +never be fed into the evaporator in the acid condition. + +In order to treat the spent lyes for evaporation, they are first allowed +to cool in the storage tank, after which any soap which may have +separated is skimmed off and returned to the soap kettle. This lye is +then pumped to the treatment tank, an ordinary tank equipped with some +method of agitating the liquor, either by a mechanical stirrer, steam +blower or compressed air, until it is about two feet from the top. + +After the lye has been skimmed off it is thoroughly agitated and a +sample taken. The amount of lye in the tank is then calculated. Spent +lye is about 1.09 times heavier than water, or weighs about 9 pounds to +the gallon. While the sample is being tested for alkalinity it is +advisable to add sulfate of alumina, which may be dissolving while the +sample is being titrated. This substance should be added in the +proportion of anywhere from 6 to 14 pounds per thousand pounds of lye, +depending upon the amount of impurities contained therein. For a clean +lye six pounds per thousand is sufficient, but for an impure lye a +greater quantity is necessary. The sulfate of alumina used should be +free from arsenic and sulfides and should contain a minimum amount of +grit (silica), as grit reduces the life of the pump valves. This may be +estimated with sufficient accuracy by rubbing the filtered-off portions, +insoluble in water between the fingers and a plate of glass. The object +of adding the sulfate of alumina is to transform the soap contained in +the lye into the insoluble aluminum soaps, and at the same time to +coagulate the albuminous impurities. It must be remembered that the +sulfate of alumina is added only for the fresh lye put into the tank. +Thus if there were 10,000 pounds of lye in the treating tank when the +fresh lye was run in, and 50,000 pounds when the tank is filled, adding +nine pounds of sulfate of alumina per thousand of lye, only 360 pounds +would be added or enough for 40,000 pounds. Sulfate of alumina +neutralizes one-third of its weight of caustic. + +To determine the alkali in the sample, 10 cubic centimeters are pipetted +into a beaker, a little distilled water added, then 3 or 4 drops of +phenolphthalein indicator. From a burette, quarter normal (N/4) sulfuric +acid is added until the pink color is just discharged. When this point +is reached 4 to 5 c. c. more of acid are added and the solution is +boiled to expel the carbon dioxide. Should the solution turn pink, it is +necessary to add more acid. After having boiled for 3 to 4 minutes, N/4 +caustic soda is added until the pink color just returns and the amount +of caustic soda used is read on the burette. The difference between the +number of cubic centimeters of N/4 sulfuric acid and N/4 caustic soda +gives the amount of alkali in the sample. By using a 10 c. c. sample and +N/4 sulfuric acid and N/4 caustic soda each c. c. obtained by the +difference of these two solutions is equal to one-tenth of one per cent. +(0.1%) of the total alkali in the lye. As an example, say we first used +7.7 c. c. of N/4 sulfuric acid to just discharge the pink, then added 4 +c. c. more, or 11.7 c. c. in total. After boiling it required 5.3 c. c. +to bring back a slight pink, the total alkalinity would be 11.7 c. c. - +5.3 c. c. = 6.4 c. c., or 0.64% total alkali in the lye in terms of +caustic soda. If there were 40,000 pounds of lye to be treated then we +should have to neutralize: + +40,000 × .0064 = 256 lbs. alkali. Since sulfate of alumina neutralizes +one-third of its weight in caustic, and there are say 9 lbs. of this +added per thousand pounds of lye we would add + +40,000 × 9 = 360 lbs. of sulfate of alumina. This would neutralize 360 × +1/3 = 120 lbs of alkali. There are then 256 - 120 = 136 lbs. of alkali +still to be neutralized. If 60° B. sulfuric acid is used it requires +about 1.54 lbs. of acid to one pound of caustic. Therefore to neutralize +the caustic soda remaining it requires: + +136 × 1.54 = 209.44 lbs. 60° B. sulfuric acid to neutralize the total +alkali in the 40,000 pounds of spent lye. + +The acid is added and the lye well stirred, after which another sample +is taken and again titrated as before. From this titration the amount of +acid to be added is again calculated and more acid is added if +necessary. Should too much acid have been added, caustic soda solution +is added until the lye is between exactly neutral and 0.02% alkaline. +The filtered lyes at this stage have a slight yellowish cast. + +To be sure that the lyes are treated correctly the precipitation test is +advisable. To carry this out filter about 50 c. c. of the treated lye +and divide into two portions in a test tube. To one portion add ammonia +drop by drop. If a cloudiness develops upon shaking, more alkali is +added to the lye in the tank. To the other portion add a few drops of 1 +to 5 sulfuric acid and shake the test tube. If a precipitate develops or +the solution clouds, more acid is needed. When the lyes are treated +right no cloudiness should develop either upon adding ammonia or the +dilute acid. + +The properly treated lye is then run through the filter press while +slightly warm and the filtered lye is fed to the evaporator from the +filtered lye tank. The lye coming from the filter press should be clear +and have a slight yellowish cast. As the pressure increases it is +necessary to clean the press or some of the press cake will pass through +the cloths. Where sodium silicate is used as a filler, the silicate +scrap should never be returned to the soap kettle until the glycerine +lyes have been withdrawn. This practice of some soapmakers is to be +strongly censured, as it causes decided difficulty in filtering the lye, +since during the treatment of the lye, free silicic acid in colloidal +form is produced by the decomposition of the sodium silicate by acid. +This often prevents filtering the treated lye even at excess pressure +and at its best retards the filtering. + +As to the filter press cake, this may be best thrown away in a small +factory. Where, however, the output of glycerine is very large it pays +to recover both the fatty acids and alumina in the press cakes. + +In some cases, especially when the lyes are very dirty and the total +residue in the crude glycerine runs high, for which there is a penalty +usually attached, a double filtration of the lye is advisable. This is +carried out by first making the lye slightly acid in reaction by the +addition of alum and acid, then filtering. This filtered lye is then +neutralized to the proper point with caustic, as already described, and +passed through the filter press again. + +While in the method of treating the lyes as given sulfuric acid is used +for neutralizing, some operators prefer to use hydrochloric acid, as +this forms sodium chloride or common salt, whereas sulfuric acid forms +sodium sulfate, having 3/5 the graining power of salt, which eventually +renders the salt useless for graining the soap, as the percentage of +sodium sulfate increases in the salt. When the salt contains 25 per +cent. sodium sulfate it is advisable to throw it away. Sulfuric acid, +however, is considerably cheaper than hydrochloric and this more than +compensates the necessity of having to eventually reject the recovered +salt. It may here also be mentioned that recovered salt contains 5-7 per +cent. glycerine which should be washed out in the evaporator before it +is thrown away. The following tables give the approximate theoretical +amounts of acids of various strengths required to neutralize one pound +of caustic soda: + +For 1 pound of caustic soda-- + + 3.25 lbs. 18° B. hydrochloric (muriatic) acid are required. + 2.92 " 20° B. " " " " " + 2.58 " 22° B. " " " " " + +For 1 pound of caustic soda-- + + 1.93 lbs. 50° B. sulphuric acid are required. + 1.54 " 60° B. " " " " + 1.28 " 66° B. " " " " + +It is, of course, feasible to neutralize the spent lye without first +determining the causticity by titrating a sample and this is often the +case. The operator under such conditions first adds the sulfate of +alumina, then the acid, using litmus paper as his indicator. +Comparatively, this method of treatment is much slower and not as +positive, as the amount of acid or alkali to be added is at all times +uncertain, for in the foaming of the lyes their action on litmus is +misleading. + +After the lye has been filtered to the filtered lye tank it is fed to +the evaporator, the method of operation of which varies somewhat with +different styles or makes. When it first enters the evaporator the lye +is about 11°-12° B. After boiling the density will gradually rise to 27° +B. and remain at this gravity for some time and during which time most +of the salt is dropped out in the salt filter. As the lye concentrates +the gravity gradually rises to 28°-30° B., which is half crude glycerine +and contains about 60 per cent. glycerine. Some operators carry the +evaporation to this point and accumulate a quantity of half crude before +going on to crude. After half crude is obtained the temperature on the +evaporator increases, the vacuum increases and the pressure on the +condensation drain goes up (using the same amount of live steam). As the +liquor grows heavier the amount of evaporation is less, and less steam +is required necessitating the regulation of the steam pressure on the +drum. When a temperature of 210° F. on the evaporator, with 26 or more +inches vacuum on the pump is arrived at, the crude stage has been +reached and the liquor now contains about 80 per cent. glycerine in +which shape it is usually sold by soap manufacturers. A greater +concentration requires more intricate apparatus. After settling a day in +the crude tank it is drummed. + +Crude glycerine (about 80 per cent. glycerol) free from salt is 33° B., +or has a specific gravity of 1.3. A sample boiled in an open dish boils +at a temperature of 155° C. or over. + + +TWITCHELL PROCESS. + +The Twitchell process of saponification consists of causing an almost +complete cleavage of fats and oils by the use of the Twitchell reagent +or saponifier, a sulfo-aromatic compound. This is made by the action of +concentrated sulfuric acid upon a solution of oleic acid or stearic acid +in an aromatic hydrocarbon. From 0.5 per cent. to 3 per cent. of the +reagent is added and saponification takes place from 12-48 hours by +heating in a current of live steam. The reaction is usually accelerated +by the presence of a few per cent. of free fatty acids as a starter. +Recently the Twitchell double reagent has been introduced through which +it is claimed that better colored fatty acids are obtained and the +glycerine is free from ash. + +The advantages claimed for the Twitchell process as outlined by +Joslin[12] are as follows: + +1. All the glycerine is separated from the stock before entering the +kettle, preventing loss of glycerine in the soap and removing glycerine +from spent lye. + +2. The liquors contain 15-20 per cent. glycerine whereas spent lyes +contain but 3-5 per cent. necessitating less evaporation and +consequently being more economical in steam, labor and time. + +3. No salt is obtained in the liquors which makes the evaporation +cheaper and removes the cause of corrosion of the evaporator; also +saves the glycerine retained by the salt. + +4. The glycerine liquors are purer and thus the treatment of the lyes is +cheaper and simpler and the evaporation less difficult. + +5. The glycerine can readily be evaporated to 90 per cent. crude rather +than 80 per cent. crude, thus saving drums, labor in handling and +freight. The glycerine furthermore receives a higher rating and price, +being known as saponification crude which develops no glycols in +refining it. + +6. The fatty acids obtained by the Twitchell saponifier may be converted +into soap by carbonates, thus saving cost in alkali. + +7. There is a decrease in the odor of many strong smelling stocks. + +8. The glycerine may be obtained from half boiled and cold made soaps as +well as soft (potash) soaps. + +While the advantages thus outlined are of decided value in the +employment of the Twitchell process, the one great disadvantage is that +the fatty acids obtained are rather dark in color and are not +satisfactorily employed for the making of a soap where whiteness of +color is desired. + +To carry out the process the previously heated oil or fat to be +saponified is run into a lead lined tank. As greases and tallow often +contain impurities a preliminary treatment with sulfuric acid is +necessary. For a grease 1.25 per cent. of half water and half 66° B. +sulfuric acid is the approximate amount. The undiluted 66° B. acid +should never be added directly, as the grease would be charred by this. +The grease should be agitated by steam after the required percentage of +acid, calculated on the weight of the grease, has been added. The wash +lye coming off should be 7°-10° B. on a good clean grease or 15°-22° B. +on cotton oil or a poor grease. As has been stated the grease is heated +before the acid is added or the condensation of the steam necessitates +the addition of more acid. After having boiled for 1-2 hours the grease +is allowed to settle for 12 hours and run off through a swivel pipe. + +After the grease has been washed, as just explained, and settled, it is +pumped into a covered wooden tank containing an open brass coil. Some of +the second lye from a previous run is usually left in this tank and the +grease pumped into this. The amount of this lye should be about +one-third to one-half the weight of the grease so that there is about 60 +per cent. by weight of grease in the tank after 24 hours boiling. Where +occasions arise when there is no second lye about 50 per cent. by weight +of distilled water to the amount of grease is run into the tank to +replace the lye. The saponifier is then added through a glass or granite +ware funnel after the contents of the tank have been brought to a boil. +If the boiling is to be continued 48 hours, 1 per cent. of saponifier is +added. For 24 hours boiling add 1.5 per cent. The boiling is continued +for 24-48 hours allowing 18 inches for boiling room or the grease will +boil over. + +After boiling has continued the required length of time the mass is +settled and the glycerine water is drawn off to the treatment tank. +Should a permanent emulsion have formed, due to adding too great an +amount of saponifier, a little sulfuric acid (0.1 per cent.-0.3 per +cent.) will readily break this. During the time this is being done the +space between the grease and the cover on the tank is kept filled with +steam as contact with the air darkens the fatty acids. + +To the grease remaining in the tank distilled water (condensed water +from steam coils) to one-half its volume is added and the boiling +continued 12-24 hours. The grease is then settled and the clear grease +run off through a swivel pipe. A layer of emulsion usually forms between +the clear grease and lye so that it may easily be determined when the +grease has all been run off. To prevent discoloration of the fatty acids +it is necessary to neutralize the lye with barium carbonate. The amount +of this to be added depends upon the percentage of saponifier used. +About 1/10 the weight of saponifier is the right amount. The barium +carbonate is added through the funnel at the top of the tank mixed with +a little water and the lye tested until it is neutral to methyl orange +indicator. When the fatty acids are thus treated they will not darken +upon exposure to the air when run off. + +Fresh grease is now pumped into the lye or water remaining in the tank +and the process repeated. + +The glycerine water or first lye is run to the treatment tank, the fat +skimmed off and neutralized with lime until it shows pink with +phenolphthalein, after having been thoroughly boiled with steam. About +0.25 per cent. lime is the proper amount to add. The mixture is then +allowed to settle and the supernatant mixture drawn off and run to the +glycerine evaporator feed tank. The lime which holds considerable +glycerine is filtered and the liquor added to the other. The evaporation +is carried out in two stages. The glycerine water is first evaporated to +about 60 per cent. glycerol, then dropped into a settling tank to settle +out the calcium sulfate. The clear liquor is then evaporated to crude +(about 90 per cent. glycerine) and the sediment filtered and also +evaporated to crude. + +As to the amount of saponifier to use on various stocks, this is best +determined by experiment as to how high a percentage gives dark colored +fatty acids. For good stock such as clean tallow, prime cottonseed oil, +corn oil, cocoanut oil and stock of this kind 0.75 per cent. saponifier +is sufficient. For poorer grades of tallow, house grease, poor +cottonseed oil, etc., 1 per cent. saponifier is required and for poorer +grade greases higher percentages. The percentage of fatty acids +developed varies in various stocks, and also varies with the care that +the operation is carried out, but is usually between 85 per cent.-95 per +cent. Due to the water taken up in the saponification process there is a +yield of about 103 pounds of fatty acids and glycerine for 100 pounds of +fat. + +The Twitchell reagent has undoubtedly caused a decided advance in the +saponification of fats and oils and has been of great value to the soap +manufacturer, because with a small expenditure it is possible to compete +with the much more expensive equipment necessary for autoclave +saponification. The drawback, however, has been that the reagent +imparted a dark color to the fatty acids obtained, due to decomposition +products forming when the reagent is made, and hence is not suitable for +use in soaps where whiteness of color is desired. + +There have recently been two new reagents introduced which act as +catalyzers in splitting fats, just as the Twitchell reagent acts, but +the fatty acids produced by the cleavage are of good color. The +saponification, furthermore, takes place more rapidly. These are the +Pfeilring reagent and Kontact reagent. + +The Pfeilring reagent is very similar to the Twitchell reagent, being +made from hydrogenated castor oil and naphthalene by sulfonation with +concentrated sulfuric acid. It is manufactured in Germany and is being +extensively used in that country with good success. + +The Kontact or Petroff reagent, discovered by Petroff in Russia, is made +from sulfonated mineral oils. Until very recently it has only been +manufactured in Europe, but now that it has been found possible to +obtain the proper mineral constituent from American petroleum, it is +being manufactured in this country, and it is very probable that it will +replace the Twitchell reagent because of the advantages derived by using +it, as compared to the old Twitchell reagent. + +The method and equipment necessary for employing either the Pfeilring or +Kontact reagents is exactly the same as in using the Twitchell process. + + +AUTOCLAVE SAPONIFICATION. + +While the introduction of the Twitchell process to a great extent +replaced the autoclave method of saponification for obtaining fatty +acids for soap making, the autoclave method is also used. This process +consists in heating the previously purified fat or oil in the presence +of lime and water, or water only, for several hours, which causes a +splitting of the glycerides into fatty acids and glycerine. The +advantage of autoclave saponification over the Twitchell process is that +a greater cleavage of the fats and oils results in less time and at a +slightly less expense. The glycerine thus obtained is also purer and of +better color than that obtained by Twitchelling the fats. + +An autoclave or digestor consists of a strongly constructed, closed +cylindrical tank, usually made of copper, and is so built as to resist +internal pressure. The digestor is usually 3 to 5 feet in diameter and +from 18 to 25 feet high. It may be set up horizontally or vertically and +is covered with an asbestos jacket to retain the heat. Various inlets +and outlets for the fats, steam, etc., as well as a pressure gauge and +safety valve are also a necessary part of the equipment. + + +LIME SAPONIFICATION. + +The saponification in an autoclave is usually carried out by introducing +the fats into the autoclave with a percentage of lime, magnesia or zinc +oxide, together with water. If the fats contain any great amount of +impurities, it is first necessary to purify them either by a treatment +with weak sulfuric acid, as described under the Twitchell process, or by +boiling them up with brine and settling out the impurities from the hot +fat. + +To charge the autoclave a partial vacuum is created therein by +condensation of steam just before running the purified oil in from an +elevated tank. The required quantity of unslaked lime, 2 to 4 per cent. +of the weight of the fat, is run in with the molten fat, together with +30 per cent. to 50 per cent. of water. While 8.7 per cent. lime is +theoretically required, practice has shown that 2 per cent. to 4 per +cent. is sufficient. The digestor, having been charged and adjusted, +steam is turned on and a pressure of 8 to 10 atmospheres maintained +thereon for a period of six to ten hours. Samples of the fat are taken +at various intervals and the percentage of free fatty acids determined. +When the saponification is completed the contents of the autoclave are +removed, usually by blowing out the digestor into a wooden settling +tank, or by first running off the glycerine water and then blowing out +the lime, soap and fatty acids. The mass discharged from the digestor +separates into two layers, the upper consisting of a mixture of lime +soap or "rock" and fatty acids, and the lower layer contains the +glycerine or "sweet" water. The glycerine water is first run off through +a clearing tank or oil separator, if this has not been done directly +from the autoclave, and the mass remaining washed once or twice more +with water to remove any glycerine still retained by the lime soap. The +calculated amount of sulfuric acid to decompose the lime "rock" is then +added, and the mass agitated until the fatty acids contained therein are +entirely set free. Another small wash is then given and the wash water +added to the glycerine water already run off. The glycerine water is +neutralized with lime, filtered and concentrated as in the Twitchell +process. + +Due to the difficulties of working the autoclave saponification with +lime, decomposing the large amount of lime soap obtained and dealing +with much gypsum formed thereby which collects as a sediment and +necessitates cleaning the tanks, other substances are used to replace +lime. Magnesia, about 2 per cent. of the weight of the fat, is used and +gives better results than lime. One-half to 1 per cent. of zinc oxide of +the weight of the fat is even better adapted and is now being +extensively employed for this purpose. In using zinc oxide it is +possible to recover the zinc salts and use them over again in the +digestor, which makes the process as cheap to work as with lime, with +far more satisfactory results. + + +ACID SAPONIFICATION. + +While it is possible to saponify fats and oils in an autoclave with the +addition of acid to the fat, unless a specially-constructed digestor is +built, the action of the acid on the metal from which the autoclave is +constructed prohibits its use. The acid saponification is therefore +carried out by another method. + +The method of procedure for acid saponification, therefore, is to first +purify the fats with dilute acid as already described. The purified, hot +or warm, dry fat is then run to a specially-built acidifier or a +lead-lined tank and from 4 per cent. to 6 per cent. of concentrated +sulfuric acid added to the fat, depending upon its character, the degree +of saponification required, temperature and time of saponification. A +temperature of 110 degrees C. is maintained and the mass mixed from four +to six hours. The tank is then allowed to settle out the tar formed +during the saponification, and the fatty acids run off to another tank +and boiled up about three times with one-third the amount of water. The +water thus obtained contains the glycerine, and after neutralization is +concentrated. + + +AQUEOUS SAPONIFICATION. + +While lime or a similar substance is ordinarily used to aid in splitting +fats in an autoclave, the old water process is still used. This is a +convenient, though slower and more dangerous method, of producing the +hydrolysis of the glyceride, as well as the simplest in that fatty acids +and glycerine in a water solution are obtained. The method consists in +merely charging the autoclave with fats and adding about 30 per cent. to +40 per cent. of their weight of water, depending on the amount of free +fatty acid and subjecting the charge to a pressure of 150 to 300 pounds, +until the splitting has taken place. This is a much higher pressure than +when lime is used and therefore a very strong autoclave is required. +Since fatty acids and pure glycerine water are obtained no subsequent +treatment of the finished charge is necessary except separating the +glycerine water and giving the fatty acids a wash with water to remove +all the glycerine from them. + + +SPLITTING FATS WITH FERMENTS. + +In discussing the causes of rancidity of oils and fats it was pointed +out that the initial splitting of these is due to enzymes, organized +ferments. In the seeds of the castor oil plant, especially in the +protoplasm of the seed, the enzyme which has the property of causing +hydrolysis of the glycerides is found. The ferment from the seeds of the +castor oil plant is now extracted and used upon a commercial basis for +splitting fats. + +The equipment necessary to carry out this method of saponification is a +round, iron, lead-lined tank with a conical bottom, preferably about +twice as long as it is wide. Open and closed steam coils are also +necessary in the tank. + +The oils are first heated and run into this tank. The right temperature +to heat these to is about 1 degree to 2 degrees above their +solidification point. For liquid oils 23 degrees C. is the proper heat +as under 20 degrees C. the cleavage takes place slowly. Fats titering 44 +degrees C. or above must be brought down in titer by mixing with them +oils of a lower titer as the ferment or enzyme is killed at about 45 +degrees C. and thus loses its power of splitting. It is also necessary +to have the fat in the liquid state or the ferment does not act. The +proper temperature must be maintained with dry steam. + +It is, of course, necessary to add water, which may be any kind desired, +condensed, water from steam coils, well, city, etc. From 30 per cent. to +40 per cent., on the average 35 per cent. of water is added, as the +amount necessary is regulated so as to not dilute the glycerine water +unnecessarily. To increase the hydrolysis a catalyzer, some neutral +salt, usually manganese sulfate is added in the proportion of 0.15 per +cent. appears to vary directly as the saponification number of the fat +or oil. The approximate percentages of fermentive substance to be added +to various oils and fats follow: + + Cocoanut oil 8 % + Palm Kernel oil 8 % + Cottonseed oil 6-7 % + Linseed oil 4-5 % + Tallow oil 8-10% + +The oil, water, manganese sulfate and ferment having been placed in the +tank in the order named, the mixture is agitated with air for about a +quarter of an hour to form an even emulsion, in which state the mass is +kept by stirring occasionally with air while the saponification is +taking place. A temperature is maintained a degree or two above the +titer point of the fat with closed steam which may be aided by covering +the tank for a period of 24 to 48 hours. The splitting takes place +rapidly at first, then proceeds more slowly. In 24 hours 80 per cent. of +the fats are split and in 48 hours 85 per cent. to 90 per cent. + +When the cleavage has reached the desired point the mass is heated to 80 +degrees-85 degrees C. with live or indirect steam while stirring with +air. Then 0.1 per cent.-0.15 per cent of concentrated sulfuric acid +diluted with water is added to break the emulsion. When the emulsion is +broken the glycerine water is allowed to settle out and drawn off. The +glycerine water contains 12 per cent. to 25 per cent. glycerine and +contains manganese sulfate, sulfuric acid and albuminous matter. Through +neutralization with lime at boiling temperature and filtration the +impurities can almost all be removed after which the glycerine water may +be fed to the evaporator. Should it be desired to overcome the trouble +due to the gypsum formed in the glycerine, the lime treatment may be +combined with a previous treatment of the glycerine water with barium +hydrate to remove the sulfuric acid, then later oxalic acid to +precipitate the lime. + +The fatty acids obtained by splitting with ferments are of very good +color and adaptable for soap making. + + +KREBITZ PROCESS. + +The Krebitz process which has been used to some extent in Europe is +based upon the conversion of the fat or oil into lime soap which is +transformed into the soda soap by the addition of sodium carbonate. To +carry out the process a convenient batch of, say, 10,000 pounds of fat +or oil, is run into a shallow kettle containing 1,200 to 1,400 pounds of +lime previously slaked with 3,700 to 4,500 pounds of water. The mass is +slowly heated with live steam to almost boiling until an emulsion is +obtained. The tank is then covered and allowed to stand about 12 hours. +The lime soap thus formed is dropped from the tank into the hopper of a +mill, finely ground and conveyed to a leeching tank. The glycerine is +washed out and the glycerine water run to a tank for evaporation. The +soap is then further washed and these washings are run to other tanks to +be used over again to wash a fresh batch of soap. About 150,000 pounds +of water will wash the soap made from 10,000 pounds of fat which makes +between 15,000 and 16,000 pounds of soap. The first wash contains +approximately 10 per cent. glycerine and under ordinary circumstances +this only need be evaporated for glycerine recovery. + +After extracting the glycerine the soap is slowly introduced into a +boiling solution of sodium carbonate or soda ash and boiled until the +soda has replaced the lime. This is indicated by the disappearance of +the small lumps of lime soap. Caustic soda is then added to saponify the +fat not converted by the lime saponification. The soap is then salted +out and allowed to settle out the calcium carbonate. This drops to the +bottom of the kettle as a heavy sludge entangling about 10 per cent. of +the soap. A portion of this soap may be recovered by agitating the +sludge with heat and water, pumping the soap off the top and filtering +the remaining sludge. + +While the soap thus obtained is very good, the percentage of glycerine +recovered is greatly increased and the cost of alkali as carbonate is +less. The disadvantages are many. Large quantities of lime are required; +it is difficult to recover the soap from the lime sludge; the operations +are numerous prior to the soap making proper and rather complicated +apparatus is required. + + +DISTILLATION OF FATTY ACIDS. + +The fatty acids obtained by various methods of saponification may be +further improved by distillation. + +In order to carry out this distillation, two methods may be pursued, +first, the continuous method, whereby the fatty acids are continually +distilled for five to six days, and, second, the two phase method, +whereby the distillation continues for 16 to 20 hours, after which the +residue is drawn off, treated with acid, and its distillate added to a +fresh charge of fatty acids. The latter method is by far the best, since +the advantages derived by thus proceeding more than compensate the +necessity of cleaning the still. Better colored fatty acids are +obtained; less unsaponifiable matter is contained therein; there is no +accumulation of impurities; the amount of neutral fat is lessened +because the treatment of the tar with acid causes a cleavage of the +neutral fat and the candle tar or pitch obtained is harder and better +and thus more valuable. + +The stills are usually built of copper, which are heated by both direct +fire and superheated steam. Distillation under vacuum is advisable. To +begin the distilling operation, the still is first filled with dry hot +fatty acids to the proper level. Superheated steam is then admitted and +the condenser is first heated to prevent the freezing of the fatty +acids, passing over into same. When the temperature reaches 230 deg. C. +the distillation begins. At the beginning, the fatty acids flow from the +condenser, an intense green color, due to the formation of copper soaps +produced by the action of the fatty acids on the copper still. This +color may easily be removed by treating with dilute acid to decompose +the copper soaps. + +In vacuum distillation, the operation is begun without the use of +vacuum. Vacuum is introduced only when the distillation has proceeded +for a time and the introduction of this must be carefully regulated, +else the rapid influence of vacuum will cause the contents of the still +to overflow. When distillation has begun a constant level of fatty acids +is retained therein by opening the feeding valve to same, and the heat +is so regulated as to produce the desired rate of distillation. As soon +as the distillate flows darker and slower, the feeding valve to the +still is shut off and the distillation continued until most of the +contents of the still are distilled off, which is indicated by a rise in +the temperature. Distillation is then discontinued, the still shut down, +and in about an hour the contents are sufficiently cool to be emptied. +The residue is run off into a proper receiving vessel, treated with +dilute acid and used in the distillation of tar. + +In the distillation of tar the same method as the above is followed, +only distillation proceeds at a higher temperature. The first portion +and last portion of the distillate from tar are so dark that it is +necessary to add them to a fresh charge of fatty acids. By a well +conducted distillation of tar about 50 per cent. of the fatty acids from +the tar can be used to mix with the distilled fatty acids. The residue +of this operation called stearine pitch or candle tar consists of a +hard, brittle, dark substance. Elastic pitch only results where +distillation has been kept constant for several days without +interrupting the process, and re-distilling the tar. In a good +distillation the distillation loss is 0.5 to 1.5% and loss in pitch +1.5%. Fatty acids which are not acidified deliver about 3% of pitch. +Very impure fats yield even a higher percentage in spite of acidifying. +For a long time it was found impossible to find any use for stearine +pitch, but in recent years a use has been found for same in the +electrical installation of cables. + +FOOTNOTES: + +[12] Journ. Ind. Eng. Chem. (1909), I, p. 654. + + + + +CHAPTER VI + +Analytical Methods. + + +While it is possible to attain a certain amount of efficiency in +determining the worth of the raw material entering into the manufacture +of soap through organoleptic methods, these are by no means accurate. It +is, therefore, necessary to revert to chemical methods to correctly +determine the selection of fats, oil or other substances used in soap +making, as well as standardizing a particular soap manufactured and to +properly regulate the glycerine recovered. + +It is not our purpose to cover in detail the numerous analytical +processes which may be employed in the examination of fats and oils, +alkalis, soap and glycerine, as these are fully and accurately covered +in various texts, but rather to give briefly the necessary tests which +ought to be carried out in factories where large amounts of soap are +made. Occasion often arises where it is impossible to employ a chemist, +yet it is possible to have this work done by a competent person or to +have someone instruct himself as just how to carry out the more simple +analyses, which is not a very difficult matter. The various standard +solutions necessary to carrying out the simpler titrations can readily +be purchased from dealers in chemical apparatus and it does not take +extraordinary intelligence for anyone to operate a burette, yet in many +soap plants in this country absolutely no attention is paid to the +examining of raw material, though many thousand pounds are handled +annually, which, if they were more carefully examined would result in +the saving of much more money than it costs to examine them or have +them at least occasionally analyzed. + + +ANALYSIS OF FATS AND OILS. + +In order to arrive at proper results in the analysis of a fat or oil, it +is necessary to have a proper sample. To obtain this a sample of several +of the packages of oil or fat is taken and these mixed or molten +together into a composite sample which is used in making the tests. If +the oil or fat is solid, a tester is used in taking the sample from the +package and if they are liquid, it is a simple matter to draw off a +uniform sample from each package and from these to form a composite +sample. + +In purchasing an oil or fat for soap making, the manufacturer is usually +interested in the amount of free fatty acid contained therein, of +moisture, the titer, the percentage of unsaponifiable matter and to +previously determine the color of soap which will be obtained where +color is an object. + + +DETERMINATION OF FREE FATTY ACIDS. + +Since the free fatty acid content of a fat or oil represents a loss of +glycerine, the greater the percentage of free fatty acid, the less +glycerine is contained in the fat or oil, it is advisable to purchase a +fat or oil with the lower free acid, other properties and the price +being the same. + +While the mean molecular weight of the mixed free fatty acids varies +with the same and different oils or fats and should be determined for +any particular analysis for accuracy, the free fatty acid is usually +expressed as oleic acid, which has a molecular weight of 282. + +To carry out the analysis 5 to 20 grams of the fat are weighed out into +an Erlenmeyer flask and 50 cubic centimeters of carefully neutralized +alcohol are added. In order to neutralize the alcohol add a few drops of +phenolphthalein solution to same and add a weak caustic soda solution +drop by drop until a very faint pink color is obtained upon shaking or +stirring the alcohol thoroughly. The mixture of fat and neutralized +alcohol is then heated to boiling and titrated with tenth normal alkali +solution, using phenolphthalein as an indicator. As only the free fatty +acids are readily soluble in the alcohol and the fat itself only +slightly mixes with it, the flask should be well agitated toward the end +of the titration. When a faint pink color remains after thoroughly +agitating the flask the end point is reached. In order to calculate the +percentage of free fatty acid as oleic acid, multiply the number of +cubic centimeters of tenth normal alkali used as read on the burette by +0.0282 and divide by the number of grams of fat taken for the +determination and multiply by 100. + +When dark colored oils or fats are being titrated it is often difficult +to obtain a good end point with phenolphthalein. In such cases about 2 +cubic centimeters of a 2 per cent. alcoholic solution of Alkali Blue 6 B +is recommended. + +Another method of directly determining the free fatty acid content of +tallow or grease upon which this determination is most often made is to +weigh out into an Erlenmeyer flask exactly 5.645 grams of a sample of +tallow or grease. Add about 75 cubic centimeters of neutralized alcohol. +Heat until it boils, then titrate with tenth normal alkali and divide +the reading by 2, which gives the percentage of free fatty acid as +oleic. If a fifth normal caustic solution is used, the reading on the +burette gives the percentage of free fatty acid directly. This method, +while it eliminates the necessity of calculation, is troublesome in that +it is difficult to obtain the exact weight of fat. + + +MOISTURE. + +To calculate the amount of moisture contained in a fat or oil 5 to 10 +grams are weighed into a flat bottom dish, together with a known amount +of clean, dry sand, if it is so desired. The dish is then heated over a +water bath, or at a temperature of 100-110 degs. C., until it no longer +loses weight upon drying and reweighing the dish. One hour should elapse +between the time the dish is put on the water bath and the time it is +taken off to reweigh. The difference between the weight of the dish is +put on the water bath and the time it is taken off when it reaches a +constant weight is moisture. This difference divided by the original +weight of the fat or oil × 100 gives the percentage of moisture. + +When highly unsaturated fats or oils are being analyzed for moisture, an +error may be introduced either by the absorption of oxygen, which is +accelerated at higher temperature, or by the formation of volatile fatty +acids. The former causes an increase in weight, the latter causes a +decrease. To obviate this, the above operation of drying should be +carried out in the presence of some inert gas like hydrogen, carbon +dioxide, or nitrogen. + + +TITER. + +The titer of a fat or oil is really an indication of the amount of +stearic acid contained therein. The titer, expressed in degrees +Centigrade, is the solidification point of the fatty acids of an oil or +fat. In order to carry out the operation a Centigrade thermometer +graduated in one or two-tenths of a degree is necessary. A thermometer +graduated between 10 degs. centigrade to 60 degs. centigrade is best +adapted and the graduations should be clear cut and distinct. + +To make the determination about 30 grams of fat are roughly weighed in a +metal dish and 30-40 cubic centimeters of a 30 per cent. (36 degs. +Baumé) solution of sodium hydroxide, together with 30-40 cubic +centimeters of alcohol, denatured alcohol will do, are added and the +mass heated until saponified. Heat over a low flame or over an asbestos +plate until the soap thus formed is dry, constantly stirring the +contents of the dish to prevent burning. The dried soap is then +dissolved in about 1000 cubic centimeters of water, being certain that +all the alcohol has been expelled by boiling the soap solution for about +half an hour. When the soap is in solution add sufficient sulphuric acid +to decompose the soap, approximately 100 cubic centimeters of 25 degs. +Baumé sulphuric acid, and boil until the fatty acids form a clear layer +on top of the liquid. A few pieces of pumice stone put into the mixture +will prevent the bumping caused by boiling. Siphon off the water from +the bottom of the dish and wash the fatty acids with boiling water until +free from sulphuric acid. Collect the fatty acids in a small casserole +or beaker and dry them over a steam bath or drying oven at 110 degs. +Centigrade. When the fatty acids are dry, cool them to about 10 degs. +above the titer expected and transfer them to a titer tube or short test +tube which is firmly supported by a cork in the opening of a salt mouth +bottle. Hang the thermometer by a cord from above the supported tube so +it reaches close to the bottom when in the titer tube containing the +fatty acids and so that it may be used as a stirrer. Stir the mass +rather slowly, closely noting the temperature. The temperature will +gradually fall during the stirring operation and finally remain +stationary for half a minute or so then rise from 0.1 to 0.5 degs. The +highest point to which the mercury rises after having been stationary is +taken as the reading of the titer. + + +DETERMINATION OF UNSAPONIFIABLE MATTER. + +In order to determine the unsaponifiable matter in fats and oils they +are first saponified, then the unsaponifiable, which consists mainly of +hydrocarbons and the higher alcohols cholesterol or phytosterol, is +extracted with ether or petroleum ether, the ether evaporated and the +residue weighed as unsaponifiable. + +To carry out the process first saponify about 5 grams of fat or oil with +an excess of alcoholic potassium hydrate, 20-30 cubic centimeters of a 1 +to 10 solution of potassium hydroxide in alcohol until the alcohol is +evaporated over a steam bath. Wash the soap thus formed into a +separatory funnel of 200 cubic centimeters capacity with 80-100 cubic +centimeters water. Then add about 60 cubic centimeters of ether, +petroleum ether or 86 degs. gasoline and thoroughly shake the funnel to +extract the unsaponifiable. Should the two layers not separate readily, +add a few cubic centimeters of alcohol, which will readily cause them to +separate. Draw off the watery solution from beneath and wash the ether +with water containing a few drops of sodium hydrate and run to another +dish. Pour the watery solution into the funnel again and repeat the +extraction once or twice more or until the ether shows no discoloration. +Combine the ether extractions into the funnel and wash with water until +no alkaline reaction is obtained from the wash water. Run the ether +extract to a weighed dish, evaporate and dry rapidly in a drying oven. +As some of the hydrocarbons are readily volatile at 100 degs. +Centigrade, the drying should not be carried on any longer than +necessary. The residue is then weighed and the original weight of fat +taken divided into the weight of the residue × 100 gives the percentage +unsaponifiable. + + +TEST FOR COLOR OF SOAP. + +It is often desirable to determine the color of the finished soap by a +rapid determination before it is made into soap. It often happens, +especially with the tallows, that a dark colored sample produces a light +colored soap, whereas a bleached light colored tallow produces a soap +off shade. + +To rapidly determine whether the color easily washes out of the tallow +with lye, 100 cubic centimeters of tallow are saponified in an enameled +or iron dish with 100 cubic centimeters of 21 degs. Baumé soda lye and +100 cubic centimeters of denatured alcohol. Continue heating over a wire +gauze until all the alcohol is expelled and then add 50 cubic +centimeters of the 21 degs. Baumé lye to grain the soap. Allow the lyes +to settle and with an inverted pipette draw off the lyes into a test +tube or bottle. Close the soap with 100 cubic centimeters of hot water +and when closed again grain with 50 cubic centimeters of the lye by just +bringing to a boil over an open flame. Again allow the lyes to settle +and put aside a sample of the lye for comparison. Repeat the process of +closing, graining and settling and take a sample of lye. If the lye is +still discolored repeat the above operations again or until the lye is +colorless. Ordinarily all the color will come out with the third lye. +The soap thus obtained contains considerable water which makes it appear +white. The soap is, therefore, dried to about 15 per cent. moisture and +examined for color. The color thus obtained is a very good criterion as +to what may be expected in the soap kettle. + +By making the above analyses of fats or oils the main properties as to +their adaptability for being made into soap are determined. In some +cases, especially where adulteration or mixtures of oils are suspected, +it is necessary to further analyze same. The methods of carrying out +these analyses are fully covered by various texts on fats and oils and +we will not go into details regarding the method of procedure in +carrying these out. + + +TESTING OF ALKALIS USED IN SOAP MAKING. + +The alkalis entering into the manufacture of soap such as caustic soda +or sodium hydroxide, caustic potash or potassium hydrate, carbonate of +soda or sodium carbonate, carbonate of potash or potassium carbonate +usually contain impurities which do not enter into combination with the +fats or fatty acids to form soap. It is out of the question to use +chemically pure alkalis in soap making, hence it is often necessary to +determine the alkalinity of an alkali. It may again be pointed out that +in saponifying a neutral fat or oil only caustic soda or potash are +efficient and the carbonate contained in these only combines to a more +or less extent with any free fatty acids contained in the oils or fats. +Caustic soda or potash or lyes made from these alkalis upon exposure to +the air are gradually converted into sodium or potassium carbonate by +the action of the carbon dioxide contained in the air. While the amount +of carbonate thus formed is not very great and is greatest upon the +surface, all lyes as well as caustic alkalis contain some carbonate. +This carbonate introduces an error in the analysis of caustic alkalis +when accuracy is required and thus in the analysis of caustic soda or +potash it is necessary to remove the carbonate when the true alkalinity +as sodium hydroxide or potassium hydroxide is desired. This may be done +by titration in alcohol which has been neutralized. + +In order to determine the alkalinity of any of the above mentioned +alkalis, it is first necessary to obtain a representative sample of the +substance to be analyzed. To do this take small samples from various +portions of the package and combine them into a composite sample. +Caustic potash and soda are hygroscopic and samples should be weighed at +once or kept in a well stoppered bottle. Sodium or potassium carbonate +can be weighed more easily as they do not rapidly absorb moisture from +the air. + +To weigh the caustic soda or potash place about five grams on a watch +glass on a balance and weigh as rapidly as possible. Wash into a 500 +cubic centimeter volumetric flask and bring to the mark with distilled +water. Pipette off 50 cubic centimeters into a 200 cubic centimeter +beaker, dilute slightly with distilled water, add a few drops of methyl +orange indicator and titrate with normal acid. For the carbonates about +1 gram may be weighed, washed into a 400 cubic centimeter beaker, +diluted with distilled water, methyl orange indicator added and titrated +with normal acid. It is advisable to use methyl orange indicator in +these titrations as phenolphthalein is affected by the carbon dioxide +generated when an acid reacts with a carbonate and does not give the +proper end point, unless the solution is boiled to expel the carbon +dioxide. Litmus may also be used as the indicator, but here again it is +necessary to boil as carbon dioxide also affects this substance. As an +aid to the action of these common indicators the following table may be +helpful: + + _Color in _Color in + _Indicator._ Acid Alkaline _Action of + Solution._ Solution._ CO_{2}._ + +Methyl orange Red Yellow Very slightly acid +Phenolphthalein Colorless Red Acid +Litmus Red Blue Acid + +It may be further stated that methyl orange at the neutral point is +orange in color. + +To calculate the percentage of effective alkali from the above +titrations, it must be first pointed out that in the case of caustic +potash or soda aliquot portions are taken. This is done to reduce the +error necessarily involved by weighing, as the absorption of water is +decided. Thus we had, say, exactly 5 grams which weighed 5.05 grams by +the time it was balanced. This was dissolved in 500 cubic centimeters of +water and 50 cubic centimeters or one tenth of the amount of the +solution was taken, or in each 50 cubic centimeters there were 0.505 +grams of the sample. We thus reduced the error of weighing by one tenth +provided other conditions introduce no error. In the case of the +carbonates the weight is taken directly. + +One cubic centimeter of a normal acid solution is the equivalent of: + + Grams. + Sodium Carbonate, Na_{2}CO_{3} 0.05305 + Sodium Hydroxide, NaOH 0.04006 + Sodium Oxide, Na_{2}O 0.02905 + Carbonate K_{2}CO_{3} 0.06908 + Potassium Hydroxide, KOH 0.05616 + Potassium Oxide, K_{2}O 0.04715 + +Hence to arrive at the alkalinity we multiply the number of cubic +centimeters, read on the burette, by the factor opposite the terms in +which we desire to express the alkalinity, divide the weight in grams +thus obtained by the original weight taken, and multiply the result by +100, which gives the percentage of alkali in the proper terms. For +example, say, we took the 0.505 grams of caustic potash as explained +above and required 8.7 cubic centimeter normal acid to neutralize the +solution, then + + 8.7 × .05616 = .4886 grams KOH in sample + + .4886 + ----- × 100 = 96.73% KOH in sample. + .505 + +Caustic potash often contains some caustic soda, and while it is +possible to express the results in terms of KOH, regardless of any +trouble that may be caused by this mixture in soap making, an error is +introduced in the results, not all the alkali being caustic potash. In +such cases it is advisable to consult a book on analysis as the analysis +is far more complicated than those given we will not consider it. The +presence of carbonates, as already stated, also causes an error. To +overcome this the alkali is titrated in absolute alcohol, filtering off +the insoluble carbonate. The soluble portion is caustic hydrate and may +be titrated as such. The carbonate remaining on the filter paper is +dissolved in water and titrated as carbonate. + + +SOAP ANALYSIS. + +To obtain a sample of a cake of soap for analysis is a rather difficult +matter as the moisture content of the outer and inner layer varies +considerably. To overcome this difficulty a borer or sampler may be run +right through the cake of soap, or slices may be cut from various parts +of the cake, or the cake may be cut and run through a meat chopper +several times and mixed. A sufficient amount of a homogeneous sample +obtained by any of these methods is preserved for the entire analysis by +keeping the soap in a securely stoppered bottle. + +The more important determinations of soap are moisture, free alkali, or +fatty acid, combined alkali and total fatty matter. Besides these it is +often necessary to determine insoluble matter, glycerine, unsaponifiable +matter, rosin and sugar. + + +MOISTURE. + +The analysis of soap for moisture, at its best, is most unsatisfactory, +for by heating it is impossible to drive off all the water, and on the +other hand volatile oils driven off by heat are a part of the loss +represented as moisture. + +The usual method of determining moisture is to weigh 2 to 3 grams of +finely shaved soap on a watch glass and heat in an oven at 105 degrees +C. for 2 to 3 hours. The loss in weight is represented as water, +although it is really impossible to drive off all the water in this way. + +To overcome the difficulties just mentioned either the Smith or Fahrion +method may be used. Allen recommends Smith's method which is said to be +truthful to within 0.25 per cent. Fahrion's method, according to the +author, gives reliable results to within 0.5 per cent. Both are more +rapid than the above manipulation. To carry out the method of Smith, 5 +to 10 grams of finely ground soap are heated over a sand bath with a +small Bunsen flame beneath it, in a large porcelain crucible. The +heating takes 20 to 30 minutes, or until no further evidence is present +of water being driven off. This may be tested by the fogging of a cold +piece of glass held over the crucible immediately upon removing the +burner. When no fog appears the soap is considered dry. Any lumps of +soap may be broken up by a small glass rod, weighed with the crucible, +and with a roughened end to more easily separate the lumps. Should the +soap burn, this can readily be detected by the odor, which, of course, +renders the analysis useless. The loss in weight is moisture. + +By Fahrion's method[13], 2 to 4 grams of soap are weighed in a platinum +crucible and about three times its weight of oleic acid, which has been +heated at 120 degrees C. until all the water is driven off and preserved +from moisture, is added and reweighed. The dish is then cautiously +heated with a small flame until all the water is driven off and all the +soap is dissolved. Care must be exercised not to heat too highly or the +oleic acid will decompose. The moment the water is all driven off a +clear solution is formed, provided no fillers are present in the soap. +The dish is then cooled in a dessicator and reweighed. The loss in +weight of acid plus soap is moisture and is calculated on the weight of +soap taken. This determination takes about fifteen minutes. + + +FREE ALKALI OR ACID. + +(_a_) _Alcoholic Method._ + +Test a freshly cut surface of the soap with a few drops of an alcoholic +phenolphthalein solution. If it does not turn red it may be assumed free +fat is present; should a red color appear, free alkali is present. In +any case dissolve 2 to 5 grams of soap in 100 cubic centimeters of +neutralized alcohol and heat to boiling until in solution. Filter off +the undissolved portion containing carbonate, etc., and wash with +alcohol. Add phenolphthalein to the filtrate and titrate with N/10 acid +and calculate the per cent. of free alkali as sodium or potassium +hydroxide. Should the filtrate be acid instead of alkaline, titrate with +N/10 alkali and calculate the percentage of free fatty acid as oleic +acid. + +The insoluble portion remaining on the filter paper is washed with water +until all the carbonate is dissolved. The washings are then titrated +with N/10 sulfuric acid and expressed as sodium or potassium carbonate. +Should borates or silicates be present it is possible to express in +terms of these. If borax is present the carbon dioxide is boiled off +after neutralizing exactly to methyl orange; cool, add mannite and +phenolphthalein and titrate the boric acid with standard alkali. + +(_b_) _Bosshard and Huggenberg Method._[14] + +In using the alcoholic method for the determination of the free alkali +or fat in soap there is a possibility of both free fat and free alkali +being present. Upon boiling in an alcoholic solution the fat will be +saponified, thus introducing an error in the analysis. The method of +Bosshard and Huggenberg overcomes this objection. Their method is +briefly as follows: + +_Reagents._ + +1. N/10 hydrochloric acid to standardize N/10 alcoholic sodium +hydroxide. + +2. Approximately N/10 alcoholic sodium hydroxide to fix and control the +N/40 stearic acid. + +3. N/40 stearic acid. Preparation: About 7.1 grams of stearic acid are +dissolved in one liter of absolute alcohol, the solution filtered, the +strength determined by titration against N/10 NaOH and then protected in +a well stoppered bottle, or better still connected directly to the +burette. + +4. A 10 per cent. solution of barium chloride. Preparation: 100 grams of +barium chloride are dissolved in one liter of distilled water and +filtered. The neutrality of the solution should be proven as it must be +neutral. + +5. [Greek: alpha] naptholphthalein indicator according to Sorenson. +Preparation: 0.1 gram of [Greek: alpha] naphtholphthalein is dissolved in +150 cubic centimeters of alcohol and 100 cubic centimeters of water. +For every 10 cubic centimeters of liquid use at least 12 drops of +indicator. + +6. Phenolphthalein solution 1 gram to 100 cubic centimeter 96 per cent. +alcohol. + +7. Solvent, 50 per cent. alcohol neutralized. + + +MANIPULATION. + +First--Determine the strength of the N/10 alcoholic sodium hydroxide in +terms of N/10 hydrochloric acid and calculate the factor, e. g.: + + 10 c.c. N/10 alcoholic NaOH = 9.95 N/10 HCl} + 10 c.c. N/10 alcoholic NaOH = 9.96 N/10 HCl} 9.96 + +The alcoholic N/10 NaOH has a factor of 0.996. + +Second--Control the N/40 stearic acid with the above alkali to obtain +its factor, e. g.: + + 40 c.c. N/40 alcoholic stearic acid = + 10.18 c.c. N/10 NaOH } + 40 c.c. N/40 alcoholic stearic acid = } 10.2 + 10.22 c.c. N/10 NaOH } + + 10.2 × F N/10 NaOH (0.996) = Factor N/40 stearic acid + + Therefore Factor N/40 stearic acid = 1.016. + +Third--About 5 grams of soap are weighed and dissolved in 100 cubic +centimeters of 50 per cent. neutralized alcohol in a 250 cubic +centimeter Erlenmeyer flask over a water bath and connected with a +reflux condensor. When completely dissolved, which takes but a few +moments, it is cooled by allowing a stream of running water to run over +the outside of the flask. + +Fourth--The soap is precipitated with 15 to 20 cubic centimeters of the +10 per cent. barium chloride solution. + +Fifth--After the addition of 2 to 5 cubic centimeters of [Greek: alpha] +naphtholphthalein solution the solution is titrated with N/40 alcoholic +stearic acid. [Greek: alpha] naphtholphthalein is red with an excess of +stearic acid. To mark the color changes it is advisable to first run a +few blanks until the eye has become accustomed to the change in the +indicator in the same way. The change from green to red can then be +carefully observed. + +Let us presume 5 grams of soap were taken for the analysis and 20 cubic +centimeters of N/40 stearic acid were required for the titration then to +calculate the amount of NaOH since the stearic factor is 1.016. + +20 × 1.016 = 20.32 N/40 stearic acid really required. + +1 cubic centimeter N/40 stearic acid = 0.02 per cent. NaOH for 5 grams +soap. + +[Greek: Delta] 20.32 cubic centimeters N/40 stearic acid = 0.02 × 20.32 +per cent. NaOH for 5 grams soap. + +Hence the soap contains 0.4064 per cent. NaOH. + +It is necessary, however, to make a correction by this method. When the +free alkali amounts to over 0.1 per cent. the correction is + 0.01, and +when the free alkali exceeds 0.4 per cent. the correction is + 0.04, +hence in the above case we multiply 0.004064 by 0.04, add this amount to +0.004064 and multiply by 100 to obtain the true percentage. Should the +alkalinity have been near 0.1 per cent. we would have multiplied by 0.01 +and added this. + +If carbonate is also present in the soap, another 5 grams of soap is +dissolved in 100 cubic centimeters of 50 per cent. alcohol and the +solution titrated directly after cooling with N/40 stearic acid, using +[Greek: alpha] naphtholphthalein or phenolphthalein as an indicator, +without the addition of barium chloride. From the difference of the two +titrations the alkali present as carbonate is determined. + +If the decomposed soap solution is colorless with phenolphthalein, free +fatty acids are present, which may be quickly determined with alcoholic +N/10 sodium hydroxide. + + +INSOLUBLE MATTER. + +The insoluble matter in soap may consist of organic or inorganic +substances. Among the organic substances which are usually present in +soap are oat meal, bran, sawdust, etc., while among the common inorganic +or mineral compounds are pumice, silex, clay, talc, zinc oxide, +infusorial earth, sand or other material used as fillers. + +To determine insoluble matter, 5 grams of soap are dissolved in 75 cubic +centimeters of hot water. The solution is filtered through a weighed +gooch crucible or filter paper. The residue remaining on the filter is +washed with hot water until all the soap is removed, is then dried to +constant weight at 105 degrees C. and weighed. From the difference in +weight of the gooch or filter paper and the dried residue remaining +thereon after filtering and drying, the total percentage of insoluble +matter may easily be calculated. By igniting the residue and reweighing +the amount of insoluble mineral matter can be readily determined. + + +STARCH AND GELATINE. + +Should starch or gelatine be present in soap it is necessary to extract +5 grams of the soap with 100 cubic centimeters of 95 per cent. +neutralized alcohol in a Soxhlet extractor until the residue on the +extraction thimble is in a powder form. If necessary the apparatus +should be disconnected and any lumps crushed, as these may contain soap. +The residue remaining on the thimble consists of all substances present +in soap, insoluble in alcohol. This is dried and weighed so that any +percentage of impurities not actually determined can be found by +difference. Starch and gelatine are separated from carbonate, sulfate +and borate by dissolving the latter out through a filter with cold +water. The starch and gelatine thus remaining can be determined by +known methods, starch by the method of direct hydrolysis[15] and +gelatine by Kjeldahling and calculating the corresponding amount of +gelatine from the percentage of nitrogen (17.9%) therein.[16] + + +TOTAL FATTY AND RESIN ACIDS. + +To the filtrate from the insoluble matter add 40 cubic centimeters of +half normal sulfuric acid, all the acid being added at once. Boil, stir +thoroughly for some minutes and keep warm on a water bath until the +fatty acids have collected as a clear layer on the surface. Cool by +placing the beaker in ice and syphon off the acid water through a +filter. Should the fatty acids not readily congeal a weighed amount of +dried bleached bees-wax or stearic acid may be added to the hot mixture. +This fuses with the hot mass and forms a firm cake of fatty acids upon +cooling. Without removing the fatty acids from the beaker, add about 300 +cubic centimeters of hot water, cool, syphon off the water through the +same filter used before and wash again. Repeat washing, cooling and +syphoning processes until the wash water is no longer acid. When this +stage is reached, dissolve any fatty acid which may have remained on the +filter with hot 95 per cent. alcohol into the beaker containing the +fatty acids. Evaporate the alcohol and dry the beaker to constant weight +over a water bath. The fatty acids thus obtained represent the combined +fatty acids, uncombined fat and hydrocarbons. + + +DETERMINATION OF ROSIN. + +If resin acids are present, this may be determined by the +Liebermann-Storch reaction. To carry out this test shake 2 cubic +centimeters of the fatty acids with 5 cubic centimeters of acetic +anhydride; warm slightly; cool; draw off the anhydride and add 1:1 +sulfuric acid. A violet color, which is not permanent, indicates the +presence of rosin in the soap. The cholesterol in linseed or fish oil, +which of course may be present in the soap, also give this reaction. + +Should resin acids be present, these may be separated by the Twitchell +method, which depends upon the difference in the behavior of the fatty +and resin acids when converted into their ethyl esters through the +action of hydrochloric acid. This may be carried out as follows: + +Three grams of the dried mixed acids are dissolved in 25 cubic +centimeters of absolute alcohol in a 100 cubic centimeter stoppered +flask; the flask placed in cold water and shaken. To this cooled +solution 25 cubic centimeters of absolute alcohol saturated with dry +hydrochloric acid is added. The flask is shaken occasionally and the +action allowed to continue for twenty minutes, then 10 grams of dry +granular zinc chloride are added, the flask shaken and again allowed to +stand for twenty minutes. The contents of the flask are then poured into +200 cubic centimeters of water in a 500 cubic centimeter beaker and the +flask rinsed out with alcohol. A small strip of zinc is placed in the +beaker and the alcohol evaporated. The beaker is then cooled and +transferred to a separatory funnel, washing out the beaker with 50 cubic +centimeters of gasoline (boiling below 80 degrees C.) and extracting by +shaking the funnel well. Draw off the acid solution after allowing to +separate and wash the gasoline with water until free from hydrochloric +acid. Draw off the gasoline solution and evaporate the gasoline. +Dissolve the residue in neutral alcohol and titrate with standard alkali +using phenolphthalein as an indicator. One cubic centimeter of normal +alkali equals 0.346 grams of rosin. The rosin may be gravimetrically +determined by washing the gasoline extract with water, it not being +necessary to wash absolutely free from acid, then adding 0.5 gram of +potassium hydroxide and 5 cubic centimeters of alcohol in 50 cubic +centimeters of water. Upon shaking the resin acids are rapidly +saponified and extracted by the dilute alkaline solution as rosin soaps, +while the ethyl esters remain in solution in the gasoline. Draw off the +soap solution, wash the gasoline solution again with dilute alkali and +unite the alkaline solutions. Decompose the alkaline soap solution with +an excess of hydrochloric acid and weigh the resin acids liberated as in +the determination of total fatty acids. + +According to Lewkowitsch, the results obtained by the volumetric method +which assumes a combining weight of 346 for resin acids, are very likely +to be high. On the other hand those obtained by the gravimetric method +are too low. + +Leiste and Stiepel[17] have devised a simpler method for the +determination of rosin. They make use of the fact that the resin acids +as sodium soaps are soluble in acetone and particularly acetone +containing two per cent. water, while the fatty acid soaps are soluble +in this solvent to the extent of only about 2 per cent. First of all it +is necessary to show that the sample to be analyzed contains a mixture +of resin and fatty acids. This may be done by the Liebermann-Storch +reaction already described. Glycerine interferes with the method. Two +grams of fatty acids or 3 grams of soap are weighed in a nickel crucible +and dissolved in 15-20 cubic centimeters of alcohol. The solution is +then neutralized with alcoholic sodium hydroxide, using phenolphthalein +as an indicator. The mass is concentrated by heat over an asbestos plate +until a slight film forms over it. Then about 10 grams of sharp, +granular, ignited sand are stirred in by means of a spatula, the alcohol +further evaporated, the mixture being constantly stirred and then +thoroughly dried in a drying oven. The solvent for the cooled mass is +acetone containing 2 per cent. water. It is obtained from acetone dried +by ignited sodium sulfate and adding 2 per cent. water by volume. One +hundred cubic centimeters of this solvent are sufficient for extracting +the above. The extraction of the rosin soap is conducted by adding 10 +cubic centimeters of acetone eight times, rubbing the mass thoroughly +with a spatula and decanting. The decanted portions are combined in a +beaker and the suspended fatty soaps allowed to separate. The mixture is +then filtered into a previously weighed flask and washed several times +with the acetone remaining. The solution of rosin soap should show no +separation of solid matter after having evaporated to half the volume +and allowing to cool. If a separation should occur another filtration +and the slightest possible washing is necessary. To complete the +analysis, the acetone is completely evaporated and the mass dried to +constant weight in a drying oven. The weight found gives the weight of +the rosin soap. In conducting the determination, it is important to dry +the mixture of soap and sand thoroughly. In dealing with potash soaps it +is necessary to separate the fatty acids from these and use them as +acetone dissolves too great a quantity of a potash soap. + + +TOTAL ALKALI. + +In the filtrate remaining after having washed the fatty acids in the +determination of total fatty and resin acids all the alkali present as +soap, as carbonate and as hydroxide remains in solution as sulfate. Upon +titrating this solution with half normal alkali the difference between +the half normal acid used in decomposing the soap and alkali used in +titrating the excess of acid gives the amount of total alkali in the +soap. By deducting the amount of free alkali present as carbonate or +hydroxide previously found the amount of combined alkali in the soap may +be calculated. + +To quickly determine total alkali in soap a weighed portion of the soap +may be ignited to a white ash and the ash titrated for alkalinity using +methyl orange as an indicator. + + +UNSAPONIFIED MATTER. + +Dissolve 5 grams of soap in 50 cubic centimeters of 50 per cent. +alcohol. Should any free fatty acids be present neutralize them with +standard alkali. Wash into a separatory funnel with 50 per cent. alcohol +and extract with 100 cubic centimeters of gasoline, boiling at 50 +degrees to 60 degrees C. Wash the gasoline with water, draw off the +watery layer. Run the gasoline into a weighed dish, evaporate the +alcohol, dry and weigh the residue as unsaponified matter. The residue +contains any hydrocarbon oils or fats not converted into soap. + + +SILICA AND SILICATES. + +The insoluble silicates, sand, etc., are present in the ignited residue +in the determination of insoluble matter. Sodium silicate, extensively +used as a filler, however, will only show itself in forming a pasty +liquid. Where it is desired to determine sodium silicate, 10 grams of +soap are ashed by ignition, hydrochloric acid added to the ash in excess +and evaporated to dryness. More hydrochloric acid is then added and the +mass is again evaporated until dry; then cooled; moistened with +hydrochloric acid; dissolved in water; filtered; washed; the filtrate +evaporated to dryness and again taken up with hydrochloric acid and +water; filtered and washed. The precipitates are then combined and +ignited. Silicon dioxide (SiO_{2}) is thus formed, which can be +calculated to sodium silicate (Na_{2}Si_{4}O_{9}). Should other metals +than alkali metals be suspected present the filtrate from the silica +determinations should be examined. + + +GLYCERINE IN SOAP. + +To determine the amount of glycerine contained in soap dissolve 25 grams +in hot water, add a slight excess of sulfuric acid and keep hot until +the fatty acids form as a clear layer on top. Cool the mass and remove +the fatty acids. Filter the acid solution into a 25 cubic centimeter +graduated flask; bring to the mark with water and determine the +glycerine by the bichromate method as described under glycerine +analysis. + +When sugar is present the bichromate would be reduced by the sugar, +hence this method is not applicable. In this case remove the fatty acids +as before, neutralize an aliquot portion with milk of lime, evaporate to +10 cubic centimeters, add 2 grams of sand and milk of lime containing +about 2 grams of calcium hydroxide and evaporate almost to dryness. +Treat the moist residue with 5 cubic centimeters of 96 per cent. +alcohol, rub the whole mass into a paste, then constantly stirring, heat +on a water bath and decant into a 250 cubic centimeter graduated flask. +Repeat the washing with 5 cubic centimeters of alcohol five or six +times, each time pouring the washings into the flask; cool the flask to +room temperature and fill to the mark with 96 per cent. alcohol, agitate +the flask until well mixed and filter through a dry filter paper. Take +200 cubic centimeters of the nitrate and evaporate to a syrupy +consistency over a safety water bath. Wash the liquor into a stoppered +flask with 20 cubic centimeters of absolute alcohol, add 30 cubic +centimeters of absolute ether 10 cubic centimeters at a time, shaking +well after each addition and let stand until clear. Pour off the +solution through a filter into a weighed dish and wash out the flask +with a mixture of three parts absolute ether and two parts absolute +alcohol. Evaporate to a syrup, dry for one hour at the temperature of +boiling water, weigh, ignite and weigh again. The loss is glycerine. +This multiplied by 5/4 gives the total loss for the aliquot portion +taken. The glycerine may also be determined by the acetin or bichromate +methods after driving off the alcohol and ether if so desired. + + +SUGAR IN SOAP. + +To determine sugar in soap, usually present in transparent soaps, +decompose a soap solution of 5 grams of soap dissolved in 100 cubic +centimeters of hot water with an excess of hydrochloric acid and +separate the fatty acids as usual. Filter the acid solution into a +graduated flask and make up to the mark. Take an aliquot containing +approximately 1 per cent. of reducing sugar and determine the amount of +sugar by the Soxhlet method.[18] + + +GLYCERINE ANALYSIS. + +The methods of analyzing glycerine varied so greatly due to the fact +that glycerine contained impurities which acted so much like glycerine +as to introduce serious errors in the determinations of crude glycerine. +This led to the appointment of committees in the United States and +Europe to investigate the methods of glycerine analysis. An +international committee met after their investigations and decided the +acetin method should control the buying and selling of glycerine, but +the more convenient bichromate method in a standardized form might be +used in factory control and other technical purposes. The following are +the methods of analysis and sampling as suggested by the international +committee: + + +SAMPLING. + +The most satisfactory method available for sampling crude glycerine +liable to contain suspended matter, or which is liable to deposit salt +on settling, is to have the glycerine sampled by a mutually approved +sampler as soon as possible after it is filled into drums, but in any +case before any separation of salt has taken place. In such cases he +shall sample with a sectional sampler (see appendix) then seal the +drums, brand them with a number for identification, and keep a record of +the brand number. The presence of any visible salt or other suspended +matter is to be noted by the sampler, and a report of the same made in +his certificate, together with the temperature of the glycerine. Each +drum must be sampled. Glycerine which has deposited salt or other solid +matter cannot be accurately sampled from the drums, but an approximate +sample can be obtained by means of the sectional sampler, which will +allow a complete vertical section of the glycerine to be taken including +any deposit. + + +ANALYSIS. + +1. _Determination of Free Caustic Alkali._--Put 20 grams of the sample +into a 100 cc. flask, dilute with approximately 50 cc. of freshly boiled +distilled water, add an excess of neutral barium chloride solution, 1 +cc. of phenolphthalein solution, make up to the mark and mix. Allow the +precipitate to settle, draw off 50 cc. of the clear liquid and titrate +with normal acid (_N_/1). Calculate the percentage of Na_{2}O existing +as caustic alkali. + +2. _Determination of Ash and Total Alkalinity._--Weigh 2 to 5 grams of +the sample in a platinum dish, burn off the glycerine over a luminous +Argand burner or other source of heat,[19] giving a low temperature, to +avoid volatilization and the formation of sulphides. When the mass is +charred to the point that water will not be colored by soluble organic +matter, lixiviate with hot distilled water, filter, wash and ignite the +residue in the platinum dish. Return the filtrate and washings to the +dish, evaporate the water, and carefully ignite without fusion. Weigh +the ash. + +Dissolve the ash in distilled water and titrate total alkalinity, using +as indicator methyl orange cold or litmus boiling. + +3. _Determination of Alkali Present as Carbonate._--Take 10 grams of the +sample, dilute with 50 cc. distilled water, add sufficient _N_/1 acid to +neutralize the total alkali found at (2), boil under a reflux condenser +for 15 to 20 minutes, wash down the condenser tube with distilled water, +free from carbon dioxide, and then titrate back with _N_/1 NaOH, using +phenolphthalein as indicator. Calculate the percentage of Na_{2}O. +Deduct the Na_{2}O found in (1). The difference is the percentage of +Na_{2}O existing as carbonate. + +4. _Alkali Combined with Organic Acids._--The sum of the percentages of +Na_{2}O found at (1) and (3) deducted from the percentage found at (2) +is a measure of the Na_{2}O or other alkali combined with organic acids. + +5. _Determination of Acidity._--Take 10 grams of the sample, dilute with +50 cc. distilled water free from carbon dioxide, and titrate with _N_/1 +NaOH and phenolphthalein. Express in terms of Na_{2}O required to +neutralize 100 grams. + +6. _Determination of Total Residue at 160° C._--For this determination +the crude glycerine should be slightly alkaline with Na_{2}CO_{3} not +exceeding 0.2 per cent. Na_{2}O, in order to prevent loss of organic +acids. To avoid the formation of polyglycerols this alkalinity must not +be exceeded. + +Ten grams of the sample are put into a 100 cc. flask, diluted with water +and the calculated quantity of _N_/1 HCl or Na_{2}CO_{3} added to give +the required degree of alkalinity. The flask is filled to 100 cc., the +contents mixed, and 10 cc. measured into a weighed Petrie or similar +dish 2.5 in. in diameter and 0.5 in. deep, which should have a flat +bottom. In the case of crude glycerine abnormally high in organic +residue a smaller amount should be taken, so that the weight of the +organic residue does not materially exceed 30 to 40 milligrams. + +The dish is placed on a water bath (the top of the 160° oven acts +equally well) until most of the water has evaporated. From this point +the evaporation is effected in the oven. Satisfactory results are +obtained in an oven[20] measuring 12 ins. cube, having an iron plate +0.75 in. thick lying on the bottom to distribute the heat. Strips of +asbestos millboard are placed on a shelf half way up the oven. On these +strips the dish containing the glycerine is placed. + +If the temperature of the oven has been adjusted to 160° C. with the +door closed, a temperature of 130° to 140° can be readily maintained +with the door partially open, and the glycerine, or most of it, should +be evaporated off at this temperature. When only a slight vapor is seen +to come off, the dish is removed and allowed to cool. + +An addition of 0.5 to 1.0 cc. of water is made, and by a rotary motion +the residue brought wholly or nearly into solution. The dish is then +allowed to remain on a water bath or top of the oven until the excess +water has evaporated and the residue is in such a condition that on +returning to the oven at 160° C. it will not spurt. The time taken up to +this point cannot be given definitely, nor is it important. Usually two +or three hours are required. From this point, however, the schedule of +time must be strictly adhered to. The dish is allowed to remain in the +oven, the temperature of which is carefully maintained at 160° C. for +one hour, when it is removed, cooled, the residue treated with water, +and the water evaporated as before. The residue is then subjected to a +second baking of one hour, after which the dish is allowed to cool in a +desiccator over sulphuric acid and weighed. The treatment with water, +etc., is repeated until a constant loss of 1 to 1.5 mg. per hour is +obtained. + +In the case of acid glycerine a correction must be made for the alkali +added 1 cc. _N_/1 alkali represents an addition of 0.03 gram. In the +case of alkaline crudes a correction should be made for the acid added. +Deduct the increase in weight due to the conversion of the NaOH and +Na_{2}CO_{3} to NaCl. The corrected weight multiplied by 100 gives the +percentage of _total residue at 160° C._ + +This residue is taken for the determination of the non-volatile +acetylizable impurities (see acetin method). + +7. _Organic residue._--Subtract the ash from the total residue at 160° +C. Report as organic residue at 160° C. (it should be noted that +alkaline salts of fatty acids are converted to carbonates on ignition +and that the CO_{3} thus derived is not included in the organic +residue). + + +ACETIN PROCESS FOR THE DETERMINATION OF GLYCEROL. + +This process is the one agreed upon at a conference of delegates from +the British, French, German and American committees, and has been +confirmed by each of the above committees as giving results nearer to +the truth than the bichromate method on crudes in general. It is the +process to be used (if applicable) whenever only one method is employed. +On pure glycerines the results are identical with those obtained by the +bichromate process. For the application of this method the crude +glycerine should not contain over 60 per cent. water. + + +REAGENTS REQUIRED. + +(_A_) _Best Acetic Anhydride._--This should be carefully selected. A +good sample must not require more than 0.1 cc. normal NaOH for +saponification of the impurities when a blank is run on 7.5 cc. Only a +slight color should develop during digestion of the blank. + +The anhydride may be tested for strength by the following method: Into a +weighed stoppered vessel, containing 10 to 20 cc. of water, run about 2 +cc. of the anhydride, replace the stopper and weigh. Let stand with +occasional shaking, for several hours, to permit the hydrolysis of all +the anhydride; then dilute to about 200 cc., add phenolphthalein and +titrate with _N_/1 NaOH. This gives the total acidity due to free acetic +acid and acid formed from the anhydride. It is worthy of note that in +the presence of much free anhydride a compound is formed with +phenolphthalein, soluble in alkali and acetic acid, but insoluble in +neutral solutions. If a turbidity is noticed toward the end of the +neutralization it is an indication that the anhydride is incompletely +hydrolyzed and inasmuch as the indicator is withdrawn from the solution, +results may be incorrect. + +Into a stoppered weighing bottle containing a known weight of recently +distilled aniline (from 10 to 20 cc.) measure about 2 cc. of the sample, +stopper, mix, cool and weigh. Wash the contents into about 200 cc. of +cold water, and titrate the acidity as before. This yields the acidity +due to the original, preformed, acetic acid plus one-half the acid due +to anhydride (the other half having formed acetanilide); subtract the +second result from the first (both calculated to 100 grams) and double +the result, obtaining the cc. _N_/1 NaOH per 100 grams of the sample. 1 +cc. _N_/NaOH equals 0.0510 anhydride. + +(_B_) _Pure Fused Sodium Acetate._--The purchased salt is again +completely fused in a platinum, silica or nickel dish, avoiding +charring, powdered quickly and kept in a stoppered bottle or desiccator. +It is most important that the sodium acetate be anhydrous. + +(_C_) _A Solution of Caustic Soda for Neutralizing, of about N_/1 +_Strength, Free from Carbonate._--This can be readily made by dissolving +pure sodium hydroxide in its own weight of water (preferably water free +from carbon dioxide) and allowing to settle until clear, or filtering +through an asbestos or paper filter. The clear solution is diluted with +water free from carbon dioxide to the strength required. + +(_D_) _N_/1 _Caustic Soda Free from Carbonate._--Prepared as above and +carefully standardized. Some caustic soda solutions show a marked +diminution in strength after being boiled; such solutions should be +rejected. + +(_E_) _N_/1 _Acid._--Carefully standardized. + +(_F_) _Phenolphthalein Solution._--0.5 per cent. phenolphthalein in +alcohol and neutralized. + + +THE METHOD. + +In a narrow-mouthed flask (preferably round-bottomed), capacity about +120 cc., which has been thoroughly cleaned and dried, weigh accurately +and as rapidly as possible 1.25 to 1.5 grams of the glycerine. A Grethan +or Lunge pipette will be found convenient. Add about 3 grams of the +anhydrous sodium acetate, then 7.5 cc. of the acetic anhydride, and +connect the flask with an upright Liebig condenser. For convenience the +inner tube of this condenser should not be over 50 cm. long and 9 to 10 +mm. inside diameter. The flask is connected to the condenser by either a +ground glass joint (preferably) or a rubber stopper. If a rubber stopper +is used it should have had a preliminary treatment with hot acetic +anhydride vapor. + +Heat the contents and keep just boiling for one hour, taking precautions +to prevent the salts drying on the sides of the flask. + +Allow the flask to cool somewhat, and through the condenser tube add 50 +cc. of distilled water free from carbon dioxide at a temperature of +about 80° C., taking care that the flask is not loosened from the +condenser. The object of cooling is to avoid any sudden rush of vapors +from the flask on adding water, and to avoid breaking the flask. Time is +saved by adding the water before the contents of the flask solidify, but +the contents may be allowed to solidify and the test proceeded with the +next day without detriment, bearing in mind that the anhydride in excess +is much more effectively hydrolyzed in hot than in cold water. The +contents of the flask may be warmed to, but must not exceed, 80° C., +until the solution is complete, except a few dark flocks representing +organic impurities in the crude. By giving the flask a rotary motion, +solution is more quickly effected. + +Cool the flask and contents without loosening from the condenser. When +quite cold wash down the inside of the condenser tube, detach the flask, +wash off the stopper or ground glass connection into the flask, and +filter the contents through an acid-washed filter into a Jena glass +flask of about 1 litre capacity. Wash thoroughly with cold distilled +water free from carbon dioxide. Add 2 cc. of phenolphthalein solution +(_F_), then run in caustic soda solution (_C_) or (_D_) until a faint +pinkish yellow color appears throughout the solution. This +neutralization must be done most carefully; the alkali should be run +down the sides of the flask, the contents of which are kept rapidly +swirling with occasional agitation or change of motion until the +solution is nearly neutralized, as indicated by the slower disappearance +of the color developed locally by the alkali running into the mixture. +When this point is reached the sides of the flask are washed down with +carbon dioxide-free water and the alkali subsequently added drop by +drop, mixing after each drop until the desired tint is obtained. + +Now run in from a burette 50 cc. or a calculated excess of _N_/1 NaOH +(_D_) and note carefully the exact amount. Boil gently for 15 minutes, +the flask being fitted with a glass tube acting as a partial condenser. +Cool as quickly as possible and titrate the excess of NaOH with _N_/1 +acid (_E_) until the pinkish yellow or chosen end-point color just +remains.[21] A further addition of the indicator at this point will +cause an increase of the pink color; this must be neglected, and the +first end-point taken. + +From the _N_/1 NaOH consumed calculate the percentage of glycerol +(including acetylizable impurities) after making the correction for the +blank test described below. + +1 cc. _N_/1 NaOH = 0.03069 gram glycerol. + +The coefficient of expansion for normal solutions is 0.00033 per cc. +for each degree centigrade. A correction should be made on this account +if necessary. + +_Blank Test._--As the acetic anhydride and sodium acetate may contain +impurities which affect the result, it is necessary to make a blank +test, using the same quantities of acetic anhydride, sodium acetate and +water as in the analysis. It is not necessary to filter the solution of +the melt in this case, but sufficient time must be allowed for the +hydrolysis of the anhydride before proceeding with the neutralization. +After neutralization it is not necessary to add more than 10 cc. of the +_N_/1 alkali (_D_), as this represents the excess usually present after +the saponification of the average soap lye crude. In determining the +acid equivalent of the _N_/1 NaOH, however, the entire amount taken in +the analysis, 50 cc., should be titrated after dilution with 300 cc. +water free from carbon dioxide and without boiling. + +_Determination of the Glycerol Value of the Acetylizable +Impurities._--The total residue at 160° C. is dissolved in 1 or 2 cc. of +water, washed into the acetylizing flask and evaporated to dryness. Then +add anhydrous sodium acetate and acetic anhydride in the usual amounts +and proceed as described in the regular analysis. After correcting for +the blank, calculate the result to glycerol. + + +WAYS OF CALCULATING ACTUAL GLYCEROL CONTENT. + +(1) Determine the apparent percentage of glycerol in the sample by the +acetin process as described. The result will include acetylizable +impurities if any are present. + +(2) Determine the total residue at 160° C. + +(3) Determine the acetin value of the residue at (2) in terms of +glycerol. + +(4) Deduct the result found at (3) from the percentage obtained at (1) +and report this corrected figure as glycerol. If volatile acetylizable +impurities are present these are included in this figure. + +Trimethyleneglycol is more volatile than glycerine and can therefore be +concentrated by fractional distillation. An approximation to the +quantity can be obtained from the spread between the acetin and +bichromate results on such distillates. The spread multiplied by 1.736 +will give the glycol. + + +BICHROMATE PROCESS FOR GLYCEROL DETERMINATION. REAGENTS REQUIRED. + +(_A_) _Pure potassium bichromate_ powdered and dried in air free from +dust or organic vapors, at 110° to 120° C. This is taken as the +standard. + +(_B_) _Dilute Bichromate Solution._--7.4564 grams of the above +bichromate are dissolved in distilled water and the solution made up to +one liter at 15.5° C. + +(_C_) _Ferrous Ammonium Sulphate._--It is never safe to assume this salt +to be constant in composition and it must be standardized against the +bichromate as follows: dissolve 3.7282 grams of bichromate (_A_) in 50 +cc. of water. Add 50 cc. of 50 per cent. sulphuric acid (by volume), and +to the cold undiluted solution add from a weighing bottle a moderate +excess of the ferrous ammonium sulphate, and titrate back with the +dilute bichromate (_B_). Calculate the value of the ferrous salt in +terms of bichromate. + +(_D_) _Silver Carbonate._--This is prepared as required for each test +from 140 cc. of 0.5 per cent. silver sulphate solution by precipitation, +with about 4.9 cc. _N_/1 sodium carbonate solution (a little less than +the calculated quantity of _N_/1 sodium carbonate should be used as an +excess to prevent rapid settling). Settle, decant and wash one by +decantation. + +(_E_) _Subacetate of Lead._--Boil a 10 per cent. solution of pure lead +acetate with an excess of litharge for one hour, keeping the volume +constant, and filter while hot. Disregard any precipitate which +subsequently forms. Preserve out of contact with carbon dioxide. + +(_F_) _Potassium Ferricyanide._--A very dilute, freshly prepared +solution containing about 0.1 per cent. + + +THE METHOD. + +Weigh 20 grams of the glycerine, dilute to 250 cc. and take 25 cc. Add +the silver carbonate, allow to stand, with occasional agitation, for +about 10 minutes, and add a slight excess (about 5 cc. in most cases) of +the basic lead acetate (_E_), allow to stand a few minutes, dilute with +distilled water to 100 cc., and then add 0.15 cc. to compensate for the +volume of the precipitate, mix thoroughly, filter through an air-dry +filter into a suitable narrow-mouthed vessel, rejecting the first 10 +cc., and return the filtrate if not clear and bright. Test a portion of +the filtrate with a little basic lead acetate, which should produce no +further precipitate (in the great majority of cases 5 cc. are ample, but +occasionally a crude will be found requiring more, and in this case +another aliquot of 25 cc. of the dilute glycerine should be taken and +purified with 6 cc. of the basic acetate). Care must be taken to avoid a +marked excess of basic acetate. + +Measure off 25 cc. of the clear filtrate into a flask or beaker +(previously cleaned with potassium bichromate and sulphuric acid). Add +12 drops of sulphuric acid (1: 4) to precipitate the small excess of +lead as sulphate. Add 3.7282 grams of the powdered potassium bichromate +(_A_). Rinse down the bichromate with 25 cc. of water and let stand with +occasional shaking until all the bichromate is dissolved (no reduction +will take place in the cold). + +Now add 50 cc. of 50 per cent. sulphuric acid (by volume) and immerse +the vessel in boiling water for two hours and keep protected from dust +and organic vapors, such as alcohol, till the titration is completed. +Add from a weighing bottle a slight excess of the ferrous ammonium +sulphate (_C_), making spot tests on a porcelain plate with the +potassium ferricyanide (_F_). Titrate back with the dilute bichromate. +From the amount of bichromate reduced calculate the percentage of +glycerol. + +1 gram glycerol = 7.4564 grams bichromate. + +1 gram bichromate = 0.13411 gram glycerol. + +The percentage of glycerol obtained above includes any oxidizable +impurities present after the purification. A correction for the +non-volatile impurities may be made by running a bichromate test on the +residue at 160° C. + + +NOTES. + +(1) It is important that the concentration of acid in the oxidation +mixture and the time of oxidation should be strictly adhered to. + +(2) Before the bichromate is added to the glycerine solution it is +essential that the slight excess of lead be precipitated with sulphuric +acid, as stipulated. + +(3) For crudes practically free from chlorides the quantity of silver +carbonate may be reduced to one-fifth and the basic lead acetate to 0.5 +cc. + +(4) It is sometimes advisable to add a little potassium sulphate to +insure a clear filtrate. + + +SAMPLING CRUDE GLYCERINE. + +The usual method of sampling crude glycerine hitherto has been by means +of a glass tube, which is slowly lowered into the drum with the object +of taking as nearly as possible a vertical section of the glycerine +contained in the drum. This method has been found unsatisfactory, owing +to the fact that in cold climates glycerine runs into the tube very +slowly, so that, owing to the time occupied, it is impossible to take a +complete section of the crude. Another objection to the glass tube is +that it fails to take anything approaching a correct proportion of any +settled salt contained in the drum. + +The sampler which is illustrated herewith has been devised with the +object of overcoming the objections to the glass tube as far as +possible. It consists of two brass tubes, one fitting closely inside the +other. A number of ports are cut out in each tube in such a way that +when the ports are opened a continuous slot is formed which enables a +complete section to be taken throughout the entire length of the drum. +By this arrangement the glycerine fills into the sampler almost +instantaneously. There are a number of ports cut at the bottom of the +sampler which render it possible to take a proportion of the salt at the +bottom of the drum. The instrument is so constructed that all the ports, +including the bottom ones, can be closed simultaneously by the simple +action of turning the handle at the top; a pointer is arranged which +indicates on a dial when the sampler is open or closed. In samplers of +larger section (1 in.) it is possible to arrange a third motion whereby +the bottom ports only are open for emptying, but in samplers of smaller +dimensions (5/8 in.) this third motion must be dispensed with, otherwise +the dimensions of the ports have to be so small that the sampler would +not be efficient. + +In using the sampler it is introduced into the drum with the ports +closed, and when it has touched the bottom, the ports are opened for a +second or two, then closed and withdrawn, and the sample discharged into +the receiving vessel by opening the ports. When the drum contains salt +which has deposited, the ports must be opened before the sampler is +pushed through the salt, thus enabling a portion to be included in the +sample. It is, however, almost impossible to obtain a correct proportion +of salt after it has settled in the drum and it is therefore recommended +that the drum be sampled before any salt has deposited. A sampler 1 in. +in diameter withdraws approximately 10 oz. from a 110-gal. drum. A +sampler 5/8 in. in diameter will withdraw about 5 oz. + +FOOTNOTES: + +[13] Zeit. Angew. Chem. 19, 385 (1906). + +[14] Zeit. Angew. Chem. 27, 11-20 (1914). + +[15] Bull. 107, Bur. Chem. U. S. Dept. Agriculture. + +[16] Richards and Gies, Am. J. Physiol. (1902) 7, 129. + +[17] Seifensieder Ztg. (1913) No. 46. + +[18] Bull 107, Bur. Chem. U. S. Dept. Agriculture. + +[19] Carbon is readily burned off completely, without loss of chlorides, +in a gas-heated muffle furnace adjusted to a dull red heat. + +[20] An electric oven suitable for this work, which is readily adjusted +to 160 degs. C., has been made for Mr. Low and the chairman, by the +Apparatus and Specialty Company, Lansing, Mich. Its size is 9-1/2 × 10 × +16 inches, and capacity 8 Petrie dishes. It gives a strong draft at +constant temperature. + +[21] A precipitate at this point is an indication of the presence of +iron or alumina, and high results will be obtained unless a correction +is made as described below. + + + + +CHAPTER VII + +Standard Methods for the Sampling and Analysis of Commercial Fats and +Oils[22] + + +The following report of the _Committee on Analysis of Commercial Fats +and Oils_ of the _Division of Industrial Chemists and Chemical +Engineers_ of the American Chemical Society was adopted April 14, 1919, +by unanimous vote: + +W. D. RICHARDSON, _Chairman_, +Swift and Co., Chicago, Ill. + +R. W. BAILEY, +Stillwell and Gladding, New York City. + +W. J. GASCOYNE, +W. J. Gascoyne and Co., Baltimore, Md. + +I. KATZ,[A] +Wilson and Co., Chicago, Ill. + +A. LOWENSTEIN,[A] +Morris and Co., Chicago, Ill. + +H. J. MORRISON, +Proctor and Gamble Co., +Ivorydale, Ohio. + +J. R. POWELL, +Armour Soap Works, Chicago, Ill. + +R. J. QUINN,[A] +Midland Chemical Co., Argo, Ill. + +PAUL RUDNICK, +Armour and Co., Chicago, Ill. + +L. M. TOLMAN, +Wilson and Co., Chicago, Ill. + +E. TWITCHELL,[A] +Emery Candle Co., Cincinnati, Ohio. + +J. J. VOLLERTSEN, +Morris and Co., Chicago, Ill. + +[Note A: Resigned.] + + +Scope, Applicability and Limitations of the Methods. + + +SCOPE. + +These methods are intended to aid in determining the commercial +valuation of fats and fatty oils in their purchase and sale, based on +the fundamental assumption commonly recognized in the trade, namely, +that the product is true to name and is not adulterated. For methods for +determining the identity of oils and fats, the absence of adulterants +therein and for specific tests used in particular industries, the +chemist is referred to standard works on the analysis of fats and oils. + + +APPLICABILITY. + +The methods are applicable in commercial transactions involving fats and +fatty oils used in the soap, candle and tanning industries, to edible +fats and oils and to fats and fatty oils intended for lubricating and +burning purposes. The methods are applicable to the raw oils used in the +varnish and paint industry with the exceptions noted under limitations, +but special methods have not been included. + + +LIMITATIONS. + +The methods have not been developed with special reference to waxes +(beeswax, carnauba wax, wool wax, etc.) although some of them may be +found applicable to these substances. The Committee considers the Wijs +method superior to the Hanus method for the determination of iodine +number of linseed oil as well as other oils, although the Hanus method +has been considered standard for this work for some time and has been +adopted by the American Society for Testing Materials and in various +specifications. It has been customary to use the Hübl method for the +determination of iodine value of tung oil (China wood oil) but the +Committee's work indicates that the Wijs method is satisfactory for this +determination. + + +Sampling. + + +TANK CARS. + +1. SAMPLING WHILE LOADING--Sample shall be taken at discharge of pipe +where it enters tank car dome. The total sample taken shall be not less +than 50 lbs. and shall be a composite of small samples of about 1 pound +each, taken at regular intervals during the entire period of loading. + +The sample thus obtained is thoroughly mixed and uniform 3-lb. portions +placed in air-tight 3-lb. metal containers. At least three such samples +shall be put up, one for the buyer, one for the seller, and the third to +be sent to a referee chemist in case of dispute. All samples are to be +promptly and correctly labeled and sealed. + +2. SAMPLING FROM CAR ON TRACK[23]--(_a_) _When contents are solid._[24] +In this case the sample is taken by means of a large tryer measuring +about 2 in. across and about 1-1/2 times the depth of the car in length. +Several tryerfuls are taken vertically and obliquely toward the ends of +the car until 50 lbs. are accumulated, when the sample is softened, +mixed and handled as under (1). In case the contents of the tank car +have assumed a very hard condition, as in Winter weather, so that it is +impossible to insert the tryer, and it becomes necessary to soften the +contents of the car by means of the closed steam coil (in nearly all +tank cars the closed steam coil leaks) or by means of open steam in +order to draw a proper sample, suitable arrangements must be made +between buyer and seller for the sampling of the car after it is +sufficiently softened, due consideration being given to the possible +presence of water in the material in the car as received and also to the +possible addition of water during the steaming. The Committee knows of +no direct method for sampling a hard-frozen tank car of tallow in a +satisfactory manner. + +(_b_) _When contents are liquid._ The sample taken is to be a 50-lb. +composite made up of numerous small samples taken from the top, bottom +and intermediate points by means of a bottle or metal container with +removable stopper or top. This device attached to a suitable pole is +lowered to the various desired depths, when the stopper or top is +removed and the container allowed to fill. The 50-lb. sample thus +obtained is handled as under (1). + +In place of the device described above, any sampler capable of taking a +sample from the top, bottom, and center, or from a section through car, +may be used. + +(_c_) _When contents are in semi-solid condition, or when stearine has +separated from liquid portions._ In this case, a combination of (_a_) +and (_b_) may be used or by agreement of the parties the whole may be +melted and procedure (_b_) followed. + + +BARRELS, TIERCES, CASKS, DRUMS, AND OTHER PACKAGES. + +All packages shall be sampled, unless by special agreement the parties +arrange to sample a lesser number; but in any case not less than 10 per +cent of the total number shall be sampled. The total sample taken shall +be at least 20 lbs. in weight for each 100 barrels, or equivalent. + +1. BARRELS, TIERCES AND CASKS--(_a_) _When contents are solid._ The +small samples shall be taken by a tryer through the bunghole or through +a special hole bored in the head or side for the purpose, with a 1-in. +or larger auger. Care should be taken to avoid and eliminate all borings +and chips from the sample. The tryer is inserted in such a way as to +reach the head of the barrel, tierce, or cask. The large sample is +softened, mixed and handled according to TANK CARS (1). + +(_b_) _When contents are liquid._ In this case use is made of a glass +tube with constricted lower end. This is inserted slowly and allowed to +fill with the liquid, when the upper end is closed and the tube +withdrawn, the contents being allowed to drain into the sample +container. After the entire sample is taken it is thoroughly mixed and +handled according to TANK CARS (1). + +(_c_) _When contents are semi-solid._ In this case the tryer or a glass +tube with larger outlet is used, depending on the degree of fluidity. + +(_d_) _Very hard materials, such as natural and artificial stearines._ +By preference the barrels are stripped and samples obtained by breaking +up contents of at least 10 per cent of the packages. This procedure is +to be followed also in the case of cakes shipped in sacks. When shipped +in the form of small pieces in sacks they can be sampled by grab +sampling and quartering. In all cases the final procedure is as outlined +under TANK CARS (1). + +2. DRUMS--Samples are to be taken as under (1), use being made of the +bunghole. The tryer or tube should be sufficiently long to reach to the +ends of the drum. + +3. OTHER PACKAGES--Tubs, pails and other small packages not mentioned +above are to be sampled by tryer or tube (depending on fluidity) as +outlined above, the tryer or tube being inserted diagonally whenever +possible. + +4. MIXED LOTS AND PACKAGES--When lots of tallow or other fats are +received in packages of various shapes and sizes, and especially wherein +the fat itself is of variable composition, such must be left to the +judgment of the sampler. If variable, the contents of each package +should be mixed as thoroughly as possible and the amount of the +individual samples taken made proportional to the sizes of the packages. + + +Analysis. + + +SAMPLE. + +The sample must be representative and at least three pounds in weight +and taken in accordance with the STANDARD METHODS FOR THE SAMPLING OF +COMMERCIAL FATS AND OILS. It must be kept in an air-tight container, in +a dark, cool place. + +Soften the sample if necessary by means of a gentle heat, taking care +not to melt it. When sufficiently softened, mix the sample thoroughly by +means of a mechanical egg beater or other equally effective mechanical +mixer. + + +MOISTURE AND VOLATILE MATTER. + +APPARATUS: _Vacuum Oven_--The Committee Standard Oven. + +DESCRIPTION--The Standard F. A. C. Vacuum Oven has been designed with +the idea of affording a simple and compact vacuum oven which will give +as uniform temperatures as possible on the shelf. As the figure shows, +it consists of an iron casting of rectangular sections with hinged front +door made tight by means of a gasket and which can be lowered on opening +the oven so as to form a shelf on which samples may be rested. The oven +contains but one shelf which is heated from above as well as below by +means of resistance coils. Several thermometer holes are provided in +order to ascertain definitely the temperature at different points on the +shelf. In a vacuum oven where the heating is done almost entirely by +radiation it is difficult to maintain uniform temperatures at all +points, but the F. A. C. oven accomplishes this rather better than most +vacuum ovens. Larger ovens containing more than one shelf have been +tried by the Committee, but have been found to be lacking in temperature +uniformity and means of control. The entire oven is supported by means +of a 4-in. standard pipe which screws into the base of the oven and +which in turn is supported by being screwed into a blind flange of +suitable diameter which rests on the floor or work table. + +_Moisture Dish_--A shallow, glass dish, lipped, beaker form, +approximately 6 to 7 cm. diameter and 4 cm. deep, shall be standard. + +DETERMINATION--Weigh out 5 grams (= 0.2 g. of the prepared sample) into +a moisture dish. Dry to constant weight in _vacuo_ at a uniform +temperature, not less than 15° C. nor more than 20° C. above the boiling +point of water at the working pressure, which must not exceed 100 mm. of +mercury.[25] Constant weight is attained when successive dryings for +1-hr. periods show an additional loss of not more that 0.05 per cent. +Report loss in weight as MOISTURE AND VOLATILE MATTER.[26] + +[Illustration: STANDARD VACUUM OVEN] + +The vacuum-oven method cannot be considered accurate in the case of fats +of the coconut oil group containing free acid and the Committee +recommends that it be used only for oils of this group when they contain +less than 1 per cent free acid. In the case of oils of this group +containing more than 1 per cent free acid, recourse should be had +temporarily to the routine control method for moisture and volatile +matter[27] until the Committee develops a more satisfactory method. + +The air-oven method cannot be considered even approximately accurate in +the case of the drying and semi-drying oils and those of the coconut oil +group. Therefore, in the case of such oils as cottonseed oil, maize oil +(corn oil), soy bean oil, linseed oil, coconut oil, palm kernel oil, +etc., the vacuum-oven method should always be used, except in the case +of fats of the coconut group containing more than 1 per cent free acid, +as noted above. + + +INSOLUBLE IMPURITIES. + +Dissolve the residue from the moisture and volatile matter determination +by heating it on a steam bath with 50 cc. of kerosene. Filter the +solution through a Gooch crucible properly prepared with asbestos,[28] +wash the insoluble matter five times with 10-cc. portions of hot +kerosene, and finally wash the residual kerosene out thoroughly with +petroleum ether. Dry the crucible and contents to constant weight, as in +the determination of moisture and volatile matter and report results as +INSOLUBLE IMPURITIES. + + +SOLUBLE MINERAL MATTER. + +Place the combined kerosene filtrate and kerosene washings from the +insoluble impurities determination in a platinum dish. Place in this an +ashless filter paper folded in the form of a cone, apex up. Light the +apex of the cone, whereupon the bulk of the kerosene burns quietly. Ash +the residue in a muffle, to constant weight, taking care that the +decomposition of alkaline earth carbonates is complete, and report the +result as SOLUBLE MINERAL MATTER.[29] When the percentage of soluble +mineral matter amounts to more than 0.1 per cent, multiply the +percentage by 10 and add this amount to the percentage of free fatty +acids as determined.[30] + + +FREE FATTY ACIDS. + +The ALCOHOL[31] used shall be approximately 95 per cent ethyl alcohol, +freshly distilled from sodium hydroxide, which with phenolphthalein +gives a definite and distinct end-point. + +DETERMINATION--Weigh 1 to 15 g. of the prepared sample into an +Erlenmeyer flask, using the smaller quantity in the case of +dark-colored, high acid fats. Add 50 to 100 cc. hot, neutral alcohol, +and titrate with _N_/2, _N_/4 or _N_/10 sodium hydroxide depending on +the fatty acid content, using phenolphthalein as indicator. Calculate to +oleic acid, except that in the case of palm oil the results may also be +expressed in terms of palmitic acid, clearly indicating the two methods +of calculation in the report. In the case of coconut and palm kernel +oils, calculate to and report in terms of lauric acid in addition to +oleic acid, clearly indicating the two methods of calculation in the +report. In the case of fats or greases containing more than 0.1 per cent +of soluble mineral matter, add to the percentages of free fatty acids as +determined 10 times the percentage of bases in the soluble mineral +matter as determined.[30] This addition gives the equivalent of fatty +acids combined with the soluble mineral matter. + + +TITER. + +STANDARD THERMOMETER--The thermometer is graduated at zero and in tenth +degrees from 10° C. to 65° C., with one auxiliary reservoir at the upper +end and another between the zero mark and the 10° mark. The cavity in +the capillary tube between the zero mark and the 10° mark is at least 1 +cm. below the 10° mark, the 10° mark is about 3 or 4 cm. above the bulb, +the length of the thermometer being about 37 cm. over all. The +thermometer has been annealed for 75 hrs. at 450° C. and the bulb is of +Jena normal 16''' glass, or its equivalent, moderately thin, so that the +thermometer will be quick-acting. The bulb is about 3 cm. long and 6 mm. +in diameter. The stem of the thermometer is 6 mm. in diameter and made +of the best thermometer tubing, with scale etched on the stem, the +graduation is clear-cut and distinct, but quite fine. The thermometer +must be certified by the U. S. Bureau of Standards. + +GLYCEROL CAUSTIC SOLUTION--Dissolve 250 g. potassium hydroxide in 1900 +cc. dynamite glycerin with the aid of heat. + +DETERMINATION--Heat 75 cc. of the glycerol-caustic solution to 150° C. +and add 50 g. of the melted fat. Stir the mixture well and continue +heating until the melt is homogeneous, at no time allowing the +temperature to exceed 150° C. Allow to cool somewhat and carefully add +50 cc. 30 per cent sulfuric acid. Now add hot water and heat until the +fatty acids separate out perfectly clear. Draw off the acid water and +wash the fatty acids with hot water until free from mineral acid, then +filter and heat to 130° C. as rapidly as possible while stirring. +Transfer the fatty acids, when cooled somewhat, to a 1-in. by 4-in. +titer tube, placed in a 16-oz. salt-mouth bottle of clear glass, fitted +with a cork that is perforated so as to hold the tube rigidly when in +position. Suspend the titer thermometer so that it can be used as a +stirrer and stir the fatty acids slowly (about 100 revolutions per +minute) until the mercury remains stationary for 30 seconds. Allow the +thermometer to hang quietly with the bulb in the center of the tube and +report the highest point to which the mercury rises as the titer of the +fatty acids. The titer should be made at about 20° C. for all fats +having a titer above 30° C. and at 10° C. below the titer for all other +fats. Any convenient means may be used for obtaining a temperature of +10° below the titer of the various fats. The committee recommends first +of all a chill room for this purpose; second, an artificially chilled +small chamber with glass window; third, immersion of the salt-mouth +bottle in water or other liquid of the desired temperature. + + +UNSAPONIFIABLE MATTER. + +EXTRACTION CYLINDER--The cylinder shall be glass-stoppered, graduated at +40 cc., 80 cc. and 130 cc., and of the following dimensions: diameter +about 1-3/8 in., height about 12 in. + +PETROLEUM ETHER--Redistilled petroleum ether, boiling under 75° C., +shall be used. A blank must be made by evaporating 250 cc. with about +0.25 g. of stearine or other hard fat (previously brought to constant +weight by heating) and drying as in the actual determination. The blank +must not exceed a few milligrams. + +DETERMINATION--Weigh 5 g. (ą0.20 g.) of the prepared sample into a +200-cc. Erlenmeyer flask, add 30 cc. of redistilled 95 per cent +(approximately) ethyl alcohol and 5 cc. of 50 per cent aqueous potassium +hydroxide, and boil the mixture for one hour under a reflux condenser. +Transfer to the extraction cylinder and wash to the 40-cc. mark with +redistilled 95 per cent ethyl alcohol. Complete the transfer, first with +warm, then with cold water, till the total volume amounts to 80 cc. Cool +the cylinder and contents to room temperature and add 50 cc. of +petroleum ether. Shake _vigorously_ for one minute and allow to settle +until both layers are clear, when the volume of the upper layer should +be about 40 cc. Draw off the petroleum ether layer as closely as +possible by means of a slender glass siphon into a separatory funnel of +500 cc. capacity. Repeat extraction at least four more times, using 50 +cc. of petroleum ether each time. More extractions than five are +necessary where the unsaponifiable matter runs high, say over 5 per +cent, and also in some cases where it is lower than 5 per cent, but is +extracted with difficulty. Wash the combined extracts in a separatory +funnel three times with 25-cc. portions of 10 per cent alcohol, shaking +vigorously each time. Transfer the petroleum ether extract to a +wide-mouth tared flask or beaker, and evaporate the petroleum ether on a +steam bath in an air current. Dry as in the method for MOISTURE AND +VOLATILE MATTER. Any blank must be deducted from the weight before +calculating unsaponifiable matter. Test the final residue for solubility +in 50 cc. petroleum ether at room temperature. Filter and wash free from +the insoluble residue, if any, evaporate and dry in the same manner as +before. The Committee wishes to emphasize the necessity of thorough and +vigorous shaking in order to secure accurate results. The two phases +must be brought into the most intimate contact possible, otherwise low +and disagreeing results may be obtained. + + +IODINE NUMBER--WIJS METHOD. + +PREPARATION OF REAGENTS--_Wijs Iodine Solution_--Dissolve 13.0 g. of +resublimed iodine in one liter of C. P. glacial acetic acid and pass in +washed and dried chlorine gas until the original thiosulfate titration +of the solution is not quite doubled. The solution is then preserved in +amber glass-stoppered bottles, sealed with paraffin until ready for use. + +Mark the date on which the solution is prepared on the bottle or +bottles and do not use Wijs solution which is more than 30 days old. + +There should be no more than a slight excess of iodine, and no excess of +chlorine. When the solution is made from iodine and chlorine, this point +can be ascertained by not quite doubling the titration.[32] + +The glacial acetic acid used for preparation of the Wijs solution should +be of 99.0 to 99.5 per cent strength. In case of glacial acetic acids of +somewhat lower strength, the Committee recommends freezing and +centrifuging or draining as a means of purification. + +_N_/10 _Sodium Thiosulfate Solution_--Dissolve 24.8 g. of C. P. sodium +thiosulfate in recently boiled distilled water and dilute with the same +to one liter at the temperature at which the titrations are to be made. + +_Starch Paste_--Boil 1 g. of starch in 200 cc. of distilled water for 10 +min. and cool to room temperature. + +An improved starch solution may be prepared by autoclaving 2 g. of +starch and 6 g. of boric acid dissolved in 200 cc. water at 15 lbs. +pressure for 15 min. This solution has good keeping qualities. + +_Potassium Iodide Solution_--Dissolve 150 g. of potassium iodide in +water and make up to one liter. + +_N_/10 _Potassium Bichromate_--Dissolve 4.903 g. of C. P. potassium +bichromate in water and make the volume up to one liter at the +temperature at which titrations are to be made. + +The Committee calls attention to the fact that occasionally potassium +bichromate is found containing sodium bichromate, although this is of +rare occurrence. If the analyst suspects that he is dealing with an +impure potassium bichromate, the purity can be ascertained by titration +against re-sublimed iodine. However, this is unnecessary in the great +majority of cases. + +_Standardization of the Sodium Thiosulfate Solution_--Place 40 cc. of +the potassium bichromate solution, to which has been added 10 cc. of the +solution of potassium iodide, in a glass-stoppered flask. Add to this 5 +cc. of strong hydro-chloric acid. Dilute with 100 cc. of water, and +allow the _N_/10 sodium thiosulfate to flow slowly into the flask until +the yellow color of the liquid has almost disappeared. Add a few drops +of the starch paste, and with constant shaking continue to add the +_N_/10 sodium thiosulfate solution until the blue color just disappears. + +DETERMINATION--Weigh accurately from 0.10 to 0.50 g. (depending on the +iodine number) of the melted and filtered sample into a clean, dry, +16-oz. glass-stoppered bottle containing 15-20 cc. of carbon +tetrachloride or chloroform. Add 25 cc. of iodine solution from a +pipette, allowing to drain for a definite time. The excess of iodine +should be from 50 per cent to 60 per cent of the amount added, that is, +from 100 per cent to 150 per cent of the amount absorbed. Moisten the +stopper with a 15 per cent potassium iodide solution to prevent loss of +iodine or chlorine but guard against an amount sufficient to run down +inside the bottle. Let the bottle stand in a dark place for 1/2 hr. at +a uniform temperature. At the end of that time add 20 cc. of 15 per cent +potassium iodide solution and 100 cc. of distilled water. Titrate the +iodine with _N_/10 sodium thiosulfate solution which is added gradually, +with constant shaking, until the yellow color of the solution has almost +disappeared. Add a few drops of starch paste and continue titration +until the blue color has entirely disappeared. Toward the end of the +reaction stopper the bottle and shake violently so that any iodine +remaining in solution in the tetrachloride or chloroform may be taken up +by the potassium iodide solution. Conduct two determinations on blanks +which must be run in the same manner as the sample except that no fat is +used in the blanks. Slight variations in temperature quite appreciably +affect the titer of the iodine solution, as acetic acid has a high +coefficient of expansion. It is, therefore, essential that the blanks +and determinations on the sample be made at the same time. The number of +cc. of standard thiosulfate solution required by the blank, less the +amount used in the determination, gives the thiosulfate equivalent of +the iodine absorbed by the amount of sample used in the determination. +Calculate to centigrams of iodine absorbed by 1 g. of sample (= per cent +iodine absorbed). + +DETERMINATION, TUNG OIL--Tung oil shows an erratic behavior with most +iodine reagents and this is particularly noticeable in the case of the +Hanus reagent which is entirely unsuitable for determining the iodine +number of this oil since extremely high and irregular results are +obtained. The Hübl solution shows a progressive absorption up to 24 hrs. +and probably for a longer time but the period required is entirely too +long for a chemical determination. The Wijs solution gives good results +if the following precautions are observed: + +Weigh out 0.15 ą 0.05 g., use an excess of 55 ą 3 per cent Wijs +solution. Conduct the absorption at a temperature of 20-25° C. for 1 hr. +In other respects follow the instructions detailed above. + + +SAPONIFICATION NUMBER (KOETTSTORFER NUMBER). + +PREPARATION OF REAGENTS. _N/2 Hydrochloric Acid_--Carefully +standardized. + +_Alcoholic Potassium Hydroxide Solution_--Dissolve 40 g. of pure +potassium hydroxide in one liter of 95 per cent redistilled alcohol (by +volume). The alcohol should be redistilled from potassium hydroxide over +which it has been standing for some time, or with which it has been +boiled for some time, using a reflux condenser. The solution must be +clear and the potassium hydroxide free from carbonates. + +DETERMINATION--Weigh accurate about 5 g. of the filtered sample into a +250 to 300 cc. Erlenmeyer flask. Pipette 50 cc. of the alcoholic +potassium hydroxide solution into the flask, allowing the pipette to +drain for a definite time. Connect the flask with an air condenser and +boil until the fat is completely saponified (about 30 minutes). Cool and +titrate with the _N_/2 hydrochloric acid, using phenolphthalein as an +indicator. Calculate the Koettstorfer number (mg. of potassium hydroxide +required to saponify 1 g. of fat). Conduct 2 or 3 blank determinations, +using the same pipette and draining for the same length of time as +above. + + +MELTING POINT. + +APPARATUS--_Capillary tubes_ made from 5 mm. inside diameter thin-walled +glass tubing drawn out to 1 mm. inside diameter. Length of capillary +part of tubes to be about 5 cm. Length of tube over all 8 cm. + +_Standard thermometer_ graduated in tenths of a degree. + +_600 cc. beaker._ + +DETERMINATION--The sample should be clear when melted and entirely free +from moisture, or incorrect results will be obtained. + +Melt and thoroughly mix the sample. Dip three of the capillary tubes +above described in the oil so that the fat in the tube stands about 1 +cm. in height. Now fuse the capillary end carefully by means of a small +blast flame and allow to cool. These tubes are placed in a refrigerator +over night at a temperature of from 40 to 50° F. They are then fastened +by means of a rubber band or other suitable means to the bulb of a +thermometer graduated in tenths of a degree. The thermometer is +suspended in a beaker of water (which is agitated by air or other +suitable means) so that the bottom of the bulb of the thermometer is +immersed to a depth of about 3 cm. The temperature of the water is +increased gradually at the rate of about 1° per minute. + +The point at which the sample becomes opalescent is first noted and the +heating continued until the contents of the tube becomes uniformly +transparent. The latter temperature is reported as the melting point. + +Before finally melting to a perfectly clear fluid, the sample becomes +opalescent and usually appears clear at the top, bottom, and sides +before becoming clear at the center. The heating is continued until the +contents of the tube become uniformly clear and transparent. This +temperature is reported as the melting point.[33] It is usually only a +fraction of a degree above the opalescent point noted. The thermometer +should be read to the nearest 1/2° C., and in addition this temperature +may be reported to the nearest degree Fahrenheit if desired. + + +CLOUD TEST. + +PRECAUTIONS--(1) The oil must be perfectly dry, because the presence of +moisture will produce a turbidity before the clouding point is reached. + +(2) The oil must be heated to 150° C. over a free flame, immediately +before making the test. + +(3) There must not be too much discrepancy between the temperature of +the bath and the clouding point of the oil. An oil that will cloud at +the temperature of hydrant water should be tested in a bath of that +temperature. An oil that will cloud in a mixture of ice and water should +be tested in such a bath. An oil that will not cloud in a bath of ice +and water must be tested in a bath of salt, ice, and water. + +DETERMINATION--The oil is heated in a porcelain casserole over a free +flame to 150° C., stirring with the thermometer. As soon as it can be +done with safety, the oil is transferred to a 4 oz. oil bottle, which +must be perfectly dry. One and one-half ounces of the oil are sufficient +for the test. A dry centigrade thermometer is placed in the oil, and the +bottle is then cooled by immersion in a suitable bath. The oil is +constantly stirred with the thermometer, taking care not to remove the +thermometer from the oil at any time during the test, so as to avoid +stirring air bubbles into the oil. The bottle is frequently removed from +the bath for a few moments. The oil must not be allowed to chill on the +sides and bottom of the bottle. This is effected by constant and +vigorous stirring with the thermometer. As soon as the first permanent +cloud shows in the body of the oil, the temperature at which this cloud +occurs is noted. + +With care, results concordant to within 1/2° C. can be obtained by this +method. A Fahrenheit thermometer is sometimes used because it has become +customary to report results in degrees Fahrenheit. + +The oil must be tested within a short time after heating to 150° C. and +a re-test must always be preceded by reheating to that temperature. The +cloud point should be approached as quickly as possible, yet not so +fast that the oil is frozen on the sides or bottom of the bottle before +the cloud test is reached. + + +Notes on the Above Methods. + + +SAMPLING. + +The standard size of sample adopted by the committee is at least 3 lbs. +in weight. The committee realizes that this amount is larger than any +samples usually furnished even when representing shipments of from +20,000 to 60,000 lbs. but it believes that the requirement of a larger +sample is desirable and will work toward uniform and more concordant +results in analysis. It will probably continue to be the custom of the +trade to submit smaller buyers' samples than required by the committee, +but these are to be considered only as samples for inspection and not +for analysis. The standard analytical sample must consist of 3 lbs. or +more. + +The reasons for keeping samples in a dark, cool place are obvious. This +is to prevent any increase in rancidity and any undue increase in free +fatty acids. In the case of many fats the committee has found in its +co-operative analytical work that free acid tends to increase very +rapidly. This tendency is minimized by low temperatures. + + +MOISTURE AND VOLATILE MATTER. + +After careful consideration the committee has decided that moisture is +best determined in a vacuum oven of the design which accompanies the +above report. Numerous results on check samples have confirmed the +committee's conclusions. The oven recommended by the committee is +constructed on the basis of well-known principles and it is hoped that +this type will be adopted generally by chemists who are called upon to +analyze fats and oils. The experiments of the committee indicate that it +is a most difficult matter to design a vacuum oven which will produce +uniform temperatures throughout; and one of the principal ideas in the +design adopted is uniformity of temperature over the entire single +shelf. This idea has not quite been realized in practice but, +nevertheless, the present design approaches much closer to the ideal +than other vacuum ovens commonly used. In the drawing the essential +dimensions are those between the heating units and the shelf and the +length and breadth of the outer casting. The standard Fat Analysis +Committee Oven (F. A. C. Oven) can be furnished by Messrs. E. H. Sargent +& Company, 125 West Lake street, Chicago. + +The committee realizes that for routine work a quicker method is +desirable and has added one such method and has also stated the +conditions under which comparable results can be obtained by means of +the ordinary well-ventilated air oven held at 105 to 110° C. However, in +accordance with a fundamental principle adopted by the committee at its +first meeting, only one standard method is adopted and declared official +for each determination. + +The committee realizes that in the case of all methods for determining +moisture by means of loss on heating there may be a loss due to volatile +matter (especially fatty acids) other than water. The title of the +determination MOISTURE AND VOLATILE MATTER indicates this idea, but any +considerable error from this source may occur only in the case of high +acid fats and oils and particularly those containing lower fatty acids +such as coconut and palm kernel oil. In the case of extracted greases +which have not been properly purified, some of the solvent may also be +included in the moisture and volatile matter determination, but inasmuch +as the solvent, usually a petroleum product, can only be considered as +foreign matter, for commercial purposes, it is entirely proper to +include it with the moisture. + +The committee has also considered the various distillation methods for +the determination of moisture in fats and oils, but since according to +the fundamental principles which it was endeavoring to follow it could +only standardize one method, it was decided that the most desirable one +on the whole was the vacuum-oven method as given. There are cases +wherein a chemist may find it desirable to check a moisture +determination or investigate the moisture content of a fat or oil +further by means of one of the distillation methods. + +However, in co-operative work the distillation method in various types +of apparatus has not yielded satisfactory results. The difficulties +appear to be connected with a proper choice of solvent and particularly +with the tendency of drops of water to adhere to various parts of the +glass apparatus instead of passing on to the measuring device. When +working on coconut oil containing a high percentage of free fatty acids, +concordant results could not be obtained by the various members of the +committee when working with identical samples, solvents and apparatus. + +On the other hand, the committee found by individual work, co-operative +work and collaborative work by several members of the committee in one +laboratory, that the old, well-known direct heating method (which the +committee has designated the hot plate method) yielded very satisfactory +results on all sorts of fats and oils including emulsions such as butter +and oleomargarine and even on coconut oil samples containing 15 to 20 +per cent free fatty acids and 5 to 6 per cent of moisture. +Unfortunately, this method depends altogether on the operator's skill +and while the method may be taught to any person whether a chemist or +not so that he can obtain excellent results with it, it is difficult to +give a sufficiently, complete description of it so that any chemist +anywhere after reading the description could follow it successfully. The +method is undoubtedly worthy of much confidence in careful hands. It is +quick, accurate and reliable. It is probably the best single method for +the determination of moisture in all sorts of samples for routine +laboratory work. On account of this fact the committee desires to +announce its willingness to instruct any person in the proper use of the +method who desires to become acquainted with it and who will visit any +committee member's laboratory. + + +INSOLUBLE IMPURITIES. + +This determination, the title for which was adopted after careful +consideration, determines the impurities which have generally been known +as dirt, suspended matter, suspended solids, foreign solids, foreign +matter, etc., in the past. The first solvent recommended by the +committee is hot kerosene to be followed by petroleum ether kept at +ordinary room temperature. Petroleum ether, cold or only slightly warm, +is not a good fat and metallic soap solvent, whereas hot kerosene +dissolves these substances readily, and for this reason the committee +has recommended the double solvent method so as to exclude metallic +soaps which are determined below as soluble mineral matter. + + +SOLUBLE MINERAL MATTER. + +Soluble mineral matter represents mineral matter combined with fatty +acids in the form of soaps in solution in the fat or oil. Formerly, this +mineral matter was often determined in combination by weighing the +separated metallic soap or by weighing it in conjunction with the +insoluble impurities. Since the soaps present consist mostly of lime +soap, it has been customary to calculate the lime present therein by +taking 0.1 the weight of the total metallic soaps. The standard method +as given above is direct and involves no calculation. The routine method +given in the note has been placed among the methods for the reason that +it is used in some laboratories, but has not been adopted as a standard +method in view of the fact that the committee has made it a rule to +adopt only one standard method. It should be pointed out, however, that +the method cannot be considered accurate for the reason that insoluble +impurities may vary from sample to sample to a considerable extent and +the error due to the presence of large particles of insoluble impurities +is thus transferred to the soluble mineral matter. The committee has +found one type of grease (naphtha bone grease) which shows most unusual +characteristics. The type sample contains 4.3 per cent soluble mineral +matter by the committee method which would be equivalent to 43.0 per +cent free fatty acid. The kerosene and gasoline filtrate was +particularly clear, nevertheless the ash was found to contain 36.43 per +cent P_{2}O_{5} equivalent to 79.60 per cent of Ca_{3}(PO_{4})_{2} and +9.63 per cent of Fe_{2}O_{3}. The method, therefore, determines the +soluble mineral matter in this case satisfactorily but the factor 10 is +not applicable for calculating the fatty acids combined therewith. It is +necessary, therefore, in order to determine the fatty acids combined +with soluble mineral matter in the original sample to determine the +actual bases in the soluble mineral matter as obtained by ashing the +kerosene and gasoline filtrate. To the bases so determined the factor 10 +can then be applied. + + +FREE FATTY ACID. + +The fatty acid method adopted is sufficiently accurate for commercial +purposes. In many routine laboratories the fat or oil is measured and +not weighed, but the committee recommends weighing the sample in all +cases. For scientific purposes the result is often expressed as "acid +number," meaning the number of milligrams of KOH required to neutralize +the free acids in one gram of fat, but the commercial practice has been, +and is, to express the fatty acids as oleic acid or in the case of palm +oil, as palmitic acid, in some instances. The committee sees no +objection to the continuation of this custom so long as the analytical +report clearly indicates how the free acid is expressed. For a more +exact expression of the free acid in a given fat, the committee +recommends that the ratio of acid number to saponification number be +used. This method of expressing results is subject to error when +unsaponifiable fatty matter is present, since the result expresses the +ratio of free fatty acid to total saponifiable fatty matter present. + + +TITER. + +At the present time the prices of glycerol and caustic potash are +abnormally high, but the committee has considered that the methods +adopted are for normal times and normal prices. For routine work during +the period of high prices the following method may be used for preparing +the fatty acids and is recommended by the committee: + +Fifty grams of fat are saponified with 60 cc. of a solution of 2 parts +of methyl alcohol to 1 of 50 per cent NaOH. The soap is dried, +pulverized and dissolved in 1000 cc. of water in a porcelain dish and +then decomposed with 25 cc. of 75 per cent sulphuric acid. The fatty +acids are boiled until clear oil is formed and then collected and +settled in a 150-cc. beaker and filtered into a 50-cc. beaker. They are +then heated to 130° C. as rapidly as possible with stirring, and +transferred, after they have cooled somewhat, to the usual 1-in. by +4-in. titer tube. + +The method of taking the titer, including handling the thermometer, to +be followed is the same as that described in the standard method. Even +at present high prices many laboratories are using the glycerol-caustic +potash method for preparing the fatty acids, figuring that the saving of +time more than compensates for the extra cost of the reagents. Caustic +soda cannot be substituted for caustic potash in the glycerol method. + +UNSAPONIFIABLE MATTER. + +The committee has considered unsaponifiable matter to include those +substances frequently found dissolved in fats and oils which are not +saponified by the caustic alkalies and which at the same time are +soluble in the ordinary fat solvents. The term includes such substances +as the higher alcohols, such as cholesterol which is found in animal +fats, phytosterol found in some vegetable fats, paraffin and petroleum +oils, etc. UNSAPONIFIABLE MATTER should not be confused in the lay mind +with INSOLUBLE IMPURITIES OR SOLUBLE MINERAL MATTER. + +The method adopted by the committee has been selected only after the +most careful consideration of other methods, such as the dry extraction +method and the wet method making use of the separatory funnel. At first +consideration the dry extraction process would seem to offer the best +basis for an unsaponifiable matter method, but in practice it has been +found absolutely impossible for different analysts to obtain agreeing +results when using any of the dry extraction methods proposed. +Therefore, this method had to be abandoned after numerous trials, +although several members of the committee strongly favored it in the +beginning. + +IODINE NUMBER--The iodine number adopted by the committee is that +determined by the well-known Wijs method. This method was adopted after +careful comparison with the Hanus and Hübl methods. The Hübl method was +eliminated from consideration almost at the beginning of the committee's +work for the reason that the time required for complete absorption of +the iodine is unnecessarily long and, in fact, even after absorption has +gone on over night, it is apparently not complete. In the case of the +Hanus and Wijs methods complete absorption takes place in from 15 +minutes to an hour, depending on conditions. Formerly, many chemists +thought the Hanus solution rather easier to prepare than the Wijs +solution, but the experience of the committee was that the Wijs solution +was no more difficult to prepare than the Hanus. Furthermore, absorption +of iodine from the Wijs solution appeared to take place with greater +promptness and certainty than from the Hanus and was complete in a +shorter time. Results by the Wijs method were also in better agreement +in the case of oils showing high iodine absorption than with the Hanus +solution and showed a slightly higher iodine absorption for the same +length of time. However, the difference was not great. The committee +investigated the question of substitution since it has been suggested +that in case of the Wijs solution substitution of iodine in the organic +molecule might occur, and found no evidence of this in the time required +for the determination, namely, 1/2 hr., or even for a somewhat longer +period. One member of the committee felt that it was not desirable to +introduce the Wijs method into these standard methods since the Hanus +method was already standardized by the Association of Official +Agricultural Chemists, but the committee felt that it must follow the +principle established at the commencement of its work, namely, that of +adopting the method which appeared to be the best from all standpoints, +taking into consideration accuracy, convenience, simplicity, time, +expense, etc., without allowing precedent to have the deciding vote. + +IODINE NUMBER, TUNG OIL--The committee has made an extensive study of +the application of the Wijs method to the determination of iodine value +in the case of tung oil with the result that it recommends the method +for this oil but has thought it desirable to limit the conditions under +which the determination is conducted rather narrowly, although +reasonably good results are obtained by the committee method without +making use of the special limitations. + +The co-operative work of the committee and the special investigations +conducted by individual members bring out the following points: + +_Influence of Temperature_--From 16° C. to 30° C. there is a moderate +increase in the absorption, but above 30° the increase is rather rapid +so that it was thought best to limit the temperature in the case of tung +oil to 20° to 25° C. + +_Influence of Time_--The absorption increases with the time but +apparently complete absorption, so far as unsaturated bonds are +concerned, occurs well within one hour's time. Consequently, one hour +was set as the practical limit. + +_Influence of Excess_--The excess of iodine solution also tends to +increase the iodine number, hence the Committee thought it necessary to +limit the excess rather rigidly to 55 ą 3 per cent, although with +greater latitude results were reasonably good. + +_Influence of Age of Solution_--Old solutions tend to give low results +although up to 2 mo. no great differences were observed. Nevertheless, +it was thought best to limit the age of the solution to 30 days--long +enough for all practical purposes. + +_Amount of Sample_--As a practical amount of sample to be weighed out +the Committee decided on 0.15 g. with a tolerance of 0.05 g. in either +direction according to preference. In other words, the amount of sample +to be taken for the determination to be from 0.1 to 0.2 g. in the +discretion of the analyst. + +The Committee's study of the Hübl method which has been adopted by the +Society for Testing Materials in the case of tung oil indicates that +this method when applied to tung oil is subject to the same influences +as the Wijs method and it has the additional very serious disadvantage +of requiring a long period of time for absorption which cannot be +considered reasonable for a modern analytical method. When using the +Hübl solution, the absorption is not complete in the case of tung oil +at 3, 7, 18 or even 24 hrs. + +The Hanus method in the case of tung oil gives very high and erratic +results, as high as 180 to 240 in ordinary cases for an oil whose true +iodine number is about 165. + + +MELTING POINT. + +A melting point is the temperature at which a solid substance assumes +the liquid condition. If the solid is a pure substance in the +crystalline condition the melting point is sharp and well defined for +any given pressure. With increased pressure the melting point is lowered +or raised, depending on whether the substance contracts or expands in +melting. The lowering or raising of the melting point with pressure is +very slight and ordinarily is not taken into consideration. +Melting-point determinations are commonly carried out under ordinary +atmospheric pressures without correction. The general effect of soluble +impurities is to lower the melting point, and this holds true whether +the impurity has a higher or lower melting point than the pure substance +(solvent). Thus if a small amount of stearic acid be added to liquid +palmitic acid and the solution frozen, the melting point of this solid +will be lower than that of palmitic acid. Likewise the melting point of +stearic acid is lowered by the addition of a small amount of palmitic +acid. A eutectic mixture results when two components solidify +simultaneously at a definite temperature. Such a mixture has a constant +melting point and because of this and also because both solid and liquid +phases have the same composition, eutectic mixtures were formerly looked +upon as compounds. The phenomenon of double melting points has been +observed in the case of a number of glycerides. Such a glyceride when +placed in the usual capillary tube and subjected to increasing +temperature quickly resolidifies only to melt again and remain melted +at a still higher temperature. This phenomenon has not yet been +sufficiently investigated to afford a satisfactory explanation. + +Non-crystalline substances such as glass, sealing wax and various other +waxes and wax mixtures, and most colloidal substances do not exhibit a +sharp melting point, but under the application of heat first soften very +gradually and at a considerably higher temperature melt sufficiently to +flow. This phenomenon of melting through a long range of temperature may +be due to the amorphous nature of the substance or to the fact that it +consists of a very large number of components of many different melting +points. + +The fats and oils of natural origin, that is, the animal and vegetable +fats and oils, consist of mixtures of glycerides and, generally +speaking, of a considerable number of such components. These components +are crystalline and when separated in the pure state have definite +melting points, although some exhibit the phenomenon of double melting +point. For the most part the naturally occurring glycerides are mixed +glycerides. In the natural fats and oils there are present also certain +higher alcohols, of which cholesterol is characteristic of the animal +fats and oils and phytosterol of many of the vegetable fats and oils. In +addition to the crystalline glycerides and the higher alcohols present +in neutral fats, there are in fats of lower grade, fatty acids, which +are crystalline, and also various non-crystalline impurities of an +unsaponifiable nature, and the presence of these impurities tends to +lower the melting point. They also tend to induce undercooling and when +the liquid fat or oil is being chilled for purposes of solidification or +in determination of titer. + +The presence of water, especially when this is thoroughly mixed or +emulsified with a fat or oil, also influences the melting point to a +marked extent, causing the mixture to melt through a longer range of +temperatures than would be the case if the water were absent. This is +particularly true of emulsified fats and oils, such as butter and +oleomargarine, both of which contain, besides water, the solids +naturally present in milk or cream and including casein, milk sugar, and +salts. The melting-point method recommended by the Committee is not +applicable to such emulsions or other watery mixtures and the Committee +has found it impossible to devise an accurate method for making +softening-point or melting-point determinations on products of this +nature. Not only the amount of water present but also the fineness of +its particles, that is, its state of subdivision and distribution, in a +fat or oil influences the softening point or melting point and causes it +to vary widely in different samples. + +As a consequence of the foregoing facts, natural fats and oils do not +exhibit a definite melting point, composed as they are of mixtures of +various crystalline glycerides, higher alcohols, fatty acids, and +non-crystalline substances. Therefore, the term melting point when +applied to them requires further definition. They exhibit first a lower +melting point (the melting point of the lowest melting component) or +what might be called the softening point and following this the fat +softens through a shorter or longer range of temperature to the final +melting point at which temperature the fat is entirely liquid. This is +the melting point determined by the Committee's melting-point method. +The range between the softening point and the final melting point varies +greatly with the different fats and oils depending on their chemical +components, the water associated with them, emulsification, etc. In the +case of coconut oil the range between softening point and final melting +point is rather short; in the case of butter, long. Various methods have +been devised to determine the so-called melting point of fats and oils. +Most of these methods, however, determine, not the melting point, but +the softening point or the flow point of the fat and the great +difficulty has been in the past to devise a method which would determine +even this point with reasonable accuracy and so that results could be +easily duplicated. It has been the aim of the Committee to devise a +simple method for the determination of the melting point of fats and +oils, but it should be understood that the term melting point in the +scientific sense is not applicable to natural fats and oils. + +FOOTNOTES: + +[22] Approved by the Supervisory Committee on Standard Methods of +Analysis of the American Chemical Society. + +[23] Live steam must not be turned into tank cars or coils before +samples are drawn, since there is no certain way of telling when coils +are free from leaks. + +[24] If there is water present under the solid material this must be +noted and estimated separately. + +[25] Boiling point of water at reduced pressures. + + Pressure Boiling Point Boiling Point Boiling Point + Mm. Hg. to 1° C. +15° C. +20° C. + 100 52° C. 67° C. 72° C. + 90 50 65 70 + 80 47 62 67 + 70 45 60 65 + 60 42 57 62 + 50 38 53 58 + 40 34 49 54 + +[26] Results comparable to those of the Standard Method may be obtained +on most fats and oils by drying 5-g. portions of the sample, prepared +and weighed as above, to constant weight in a well-constructed and +well-ventilated air oven held uniformly at a temperature of 105° to 110° +C. The thermometer bulb should be close to the sample. The definition of +constant weight is the same as for the Standard Method. + +[27] The following method is suggested by the Committee for routine +control work: Weigh out 5- to 25-g. portions of prepared sample into a +glass or aluminum (_Caution_: Aluminum soap may be formed) beaker or +casserole and heat on a heavy asbestos board over burner or hot plate, +taking care that the temperature of the sample does not go above 130° C. +at any time. During the heating rotate the vessel gently on the board by +hand to avoid sputtering or too rapid evolution of moisture. The proper +length of time of heating is judged by absence of rising bubbles of +steam, by the absence of foam or by other signs known to the operator. +Avoid overheating of sample as indicated by smoking or darkening. Cool +in desiccator and weigh. + +By co-operative work in several laboratories, the Committee has +demonstrated that this method can be used and satisfactory results +obtained on coconut oil even when a considerable percentage of free +fatty acids is present, and the method is recommended for this purpose. +Unfortunately on account of the very great personal factor involved, the +Committee cannot establish this method as a preferred method. +Nevertheless, after an operator has learned the technique of the method, +it gives perfectly satisfactory results for ordinary oils and fats, +butter, oleomargarine and coconut oil, and deserves more recognition +than it has heretofore received. + +[28] For routine control work, filter paper is sometimes more convenient +than the prepared Gooch crucible, but must be very carefully washed, +especially around the rim, to remove the last traces of fat. + +[29] For routine work, an ash may be run on the original fat, and the +soluble mineral matter obtained by deducting the ash on the insoluble +impurities from this. In this case the Gooch crucible should be prepared +with an ignited asbestos mat so that the impurities may be ashed +directly after being weighed. In all cases ignition should be to +constant weight so as to insure complete decomposition of carbonates. + +[30] See note on Soluble Mineral Matter following these methods. When +the ash contains phosphates the factor 10 cannot be applied, but the +bases consisting of calcium oxide, etc., must be determined, and the +factor 10 applied to them. + +[31] For routine work methyl or denatured ethyl alcohol of approximately +95 per cent strength may be used. With these reagents the end-point is +not sharp. + +[32] P. C. McIlhiney, _J. Am. Chem. Soc._, 29 (1917), 1222, gives the +following details for the preparation of the iodine monochloride +solution: + +The preparation of the iodine monochloride solution presents no great +difficulty, but it must be done with care and accuracy in order to +obtain satisfactory results. There must be in the solution no sensible +excess either of iodine or more particularly of chlorine, over that +required to form the monochloride. This condition is most satisfactorily +attained by dissolving in the whole of the acetic acid to be used the +requisite quantity of iodine, using a gentle heat to assist the +solution, if it is found necessary, setting aside a small portion of +this solution, while pure and dry chlorine is passed into the remainder +until the halogen content of the whole solution is doubled. Ordinarily +it will be found that by passing the chlorine into the main part of the +solution until the characteristic color of free iodine has just been +discharged there will be a slight excess of chlorine which is corrected +by the addition of the requisite amount of the unchlorinated portion +until all free chlorine has been destroyed. A slight excess of iodine +does little or no harm, but excess of chlorine must be avoided. + +[33] The melting point of oils may be determined in general according to +the above procedure, taking into consideration the lower temperature +required. + + + + +PLANT AND MACHINERY + +Illustrations of machinery and layouts of the plant of a modern +soap-making establishment. + +[Illustration: HOIST, LYE TANK, ETC.] + +[Illustration: MELTING-OUT TROUGH] + +[Illustration: LAUNDRY SOAP PLANT] + +[Illustration: DRYING RACK] + +[Illustration: SOAP KETTLE] + +[Illustration: REMELTER] + +[Illustration: CRUTCHER (Cross Section)] + +[Illustration: HORIZONTAL CRUTCHER] + +[Illustration: CRUTCHER] + +[Illustration: WRAPPING MACHINE (LAUNDRY SOAP)] + +[Illustration: SLABBER] + +[Illustration: CUTTING TABLE] + +[Illustration: AUTOMATIC POWER CUTTING TABLE] + +[Illustration: AUTOMATIC PRESS (LAUNDRY)] + +[Illustration: CUTTING TABLE (HAND)] + +[Illustration: CARTON WRAPPING MACHINE] + +[Illustration: DRYING RACKS] + +[Illustration: SOAP POWDER BOX] + +[Illustration: SCOURING SOAP PRESS] + +[Illustration: FRAME] + +[Illustration: SOAP POWDER EQUIPMENT] + +[Illustration: FLUFFY SOAP POWDER EQUIPMENT] + +[Illustration: SOAP POWDER MIXER] + +[Illustration: SOAP POWDER MILL] + +[Illustration: TOILET SOAP EQUIPMENT] + +[Illustration: TOILET SOAP DRYER] + +[Illustration: MILLING BOX] + +[Illustration: AMALGAMATOR] + +[Illustration: TOILET SOAP MILL] + +[Illustration: TOILET SOAP MILL] + +[Illustration: CHIPPER] + +[Illustration: PLODDER] + +[Illustration: HORIZONTAL CHIPPER] + +[Illustration: AMALGAMATOR (IMPROVED)] + +[Illustration: PRESS (LETTERING ON 4 SIDES OF CAKE)] + +[Illustration: Press (Foot)] + +[Illustration: Press (Foot)] + +[Illustration: PLODDER] + +[Illustration: AUTOMATIC PRESS (TOILET)] + +[Illustration: MULTIPLE CAKE CUTTER] + +[Illustration: CAKE CUTTER] + +[Illustration: CHIPPER] + +[Illustration: GLYCERINE DISTILLING PLANT] + +[Illustration: CRUDE GLYCERINE PLANT] + +[Illustration: H-A FATTY ACID DISTILLING PLANT] + + + + +Appendix + +Tables marked * are taken from the German Year Book for Soap Industry. + + +(U. S. BUREAU OF STANDARDS) + +THE METRIC SYSTEM. + +The fundamental unit of the metric system is the meter (the unit of +length). From this the units of mass (gram) and capacity (liter) are +derived. All other units are the decimal sub-divisions or multiples of +these. These three units are simply related, so that for all practical +purposes the volume of one kilogram of water (one liter) is equal to one +cubic decimeter. + + +============================================================ + | +Prefixes. Meaning. | Units. +________________________________________|___________________ + | +Milli- = one thousandth 1-1000 .001 | +Centi- = one hundredth 1-100 .01 | Meter for length. +Deci- = one tenth 1-10 .1 | +Unit = one 1. | Gram for mass. +Deka- = ten 10-1 10. | +Hecto- = one hundred 100-1 100. | Liter for capacity. +Kilo- = one thousand 1000-1 1000. | +============================================================ + +The metric terms are formed by combining the words "Meter," "Gram" and +"Liter" with the six numerical prefixes. + + +LENGTH + +10 milli-meters mm = 1 centi-meter c m + +10 centi-meters = 1 deci-meter d m + +10 deci-meters = 1 meter (about 40 inches) m + +10 meters = 1 deka-meter d k m + +10 deka-meters = 1 hecto-meter h m + +10 hecto-meters = 1 kilo-meter (about 5/8 mile) k m + + +MASS. + +10 milli-grams. m g = 1 centi-gram c g +10 centi-grams = 1 deci-gram d g +10 deci-grams = 1 gram (about 15 grains) g +10 grams = 1 deka-gram d k g +10 Deka-grams = 1 hecto-gram h g +10 hecto-grams = 1 kilo-gram (about 2 pounds) k g + + +CAPACITY. + +10 milli-liters. m l = 1 centi-liter c l +10 centi-liters = 1 deci-liter d l +10 deci-liters = 1 liter (about 1 quart) l +10 liters = 1 deka-liter d k l +10 deka-liters = 1 hecto-liter (about a barrel) h l +10 hecto-liters = 1 kilo-liter k l + +The square and cubic units are the squares and cubes of the linear +units. + +The ordinary unit of land area is the Hectare (about 2-1/2 acres). + + +U.S. BUREAU OF STANDARDS TABLE OF METRIC EQUIVALENTS + + +Meter = 39.37 inches. + +Legal Equivalent Adopted by Act of Congress July 28, 1866. + + +LENGTH. + +Centimeter = 0.3937 inch +Meter = 3.28 feet +Meter = 1.094 yards +Kilometer = 0.621 statute mile +Kilometer = 0.5396 nautical mile +Inch = 2.540 centimeters +Foot = 0.305 meter +Yard = 0.914 meter +Statute mile = 1.61 kilometers +Nautical mile = 1.853 kilometers + + +AREA. + +Sq. centimeter = 0.155 sq. inch +Sq. meter = 10.76 sq. feet +Sq. meter = 1.196 sq. yards +Hectare = 2.47 acres +Sq. kilometer = 0.386 sq. mile +Sq. inch = 6.45 sq. centimeters +Sq. foot = 0.0929 sq. meter +Sq. yard = 0.836 sq. meter +Acre = 0.405 hectare +Sq. mile = 2.59 sq. kilometers + + +WEIGHT. + +Gram = 15.43 grains +Gram = 0.772 U. S. apoth. scruple +Gram = 0.2572 U. S. apoth. dram +Gram = 0.0353 avoir. ounce +Gram = 0.03215 troy ounce +Kilogram = 2.205 avoir. pounds +Kilogram = 2.679 troy pounds +Metric ton = 0.984 gross or long ton +Metric ton = 1.102 short or net tons +Grain = 0.064 gram +U. S. apoth. scruple = 1.296 grams +U. S. apoth. dram = 3.89 grams +Avoir. ounce = 28.35 grams +Troy ounce = 31.10 grams +Avoir. pound = 0.4536 kilogram +Troy pound = 0.373 kilogram +Gross or long ton = 1.016 metric tons +Short or net ton = 0.907 metric ton + + +VOLUME. + +Cu. centimeter = 0.0610 cu. inch +Cu. meter = 35.3 cu. feet +Cu. meter = 1.308 cu. yards +Cu. inch = 16.39 cu. centimeters +Cu. foot = 0.283 cu. meter +Cu. yard = 0.765 cu. meter + + +CAPACITY. + +Millimeter = 0.0338 U. S. liq. ounce +Millimeter = 0.2705 U. S. apoth. dram +Liter = 1.057 U. S. liq. quarts +Liter = 0.2642 U. S. liq. gallon +Liter = 0.908 U. S. dry quart +Dekaliter = 1.135 U. S. pecks +Hectoliter = 2.838 U. S. bushels +U. S. liq. ounce = 29.57 millimeters +U. S. apoth. dram = 3.70 millimeters +U. S. liq. quarts = 0.946 liter +U. S. dry quarts = 1.101 liters +U. S. liq. gallon = 3.785 liters +U. S. peck = 0.881 dekaliter +U. S. bushel = 0.3524 hectoliter + + +AVOIRDUPOIS WEIGHT. + +1 pound = 16 ounces = 256 drams + 1 ounce = 16 " + + +TROY (APOTHECARIES') WEIGHT (U. S.) + +1 pound = 12 ounces = 96 drams = 288 scruples = 5,760 grains + 1 ounce = 8 drams = 24 scruples = 480 grains + 1 dram = 3 scruples = 60 grains + 1 scruple = 20 grains + + +WINE (APOTHECARIES) LIQUID MEASURE (U. S.) + +1 gallon = 8 pints = 128 fl. ozs. = 1,024 fl. drams = 61,440 minims + 1 pint = 16 fl. ozs. = 128 fl. drams = 7,689 minims + 1 fl. oz. = 8 fl. drams = 480 minims + 1 fl. dram = 60 minims + +_To find diameter of a circle_ multiply circumference by .31831. + +_To find circumference of a circle_, multiply diameter by 3.1416. + +_To find area of a circle_, multiply square of diameter by .7854. + +_To find surface of a ball_, multiply square of diameter by 3.1416. + +_To find side of an equal square_, multiply diameter by .8862. + +_To find cubic inches in a ball_, multiply cube of diameter by .5236. + +_Doubling the diameter of a pipe_, increases its capacity four times. + +_One cubic foot of anthracite coal_ weighs about 53 lbs. + +_One cubic foot of bituminous coal_ weighs from 47 to 50 pounds. + +_A gallon of water_ (U. S. standard) weighs 8-1/3 pounds and contains +231 cubic inches. + +_A cubic foot of water_ contains 7-1/2 gallons, 1728 cubic inches and +weighs 62-1/2 pounds. + +_To find the number of pounds of water a cylindrical_ tank contains, +square the diameter, multiply by .785 and then by the height in feet. +This gives the number of cubic feet which multiplied by 62-1/2 gives the +capacity in pounds of water. Divide by 7-1/2 and this gives the capacity +in gallons. + +_A horse-power_ is equivalent to raising 33,000 pounds 1 foot per +minute, or 550 pounds 1 foot per second. + +_The friction of water in pipes_ is as the square of velocity. The +capacity of pipes is as the square of their diameters; thus, doubling +the diameter of a pipe increases its capacity four times. + +_To find the diameter of a pump cylinder_ to move a given quantity of +water per minute (100 feet of piston being the standard of speed), +divide the number of gallons by 4, then extract the square root, and the +product will be the diameter in inches of the pump cylinder. + +_To find the horse-power necessary to elevate water_ to a given height, +multiply the weight of the water elevated per minute in pounds by the +height in feet, and divide the product by 33,000 (an allowance should be +added for water friction, and a further allowance for loss in steam +cylinder, say from 20 to 30 per cent). + +_To compute the capacity of pumping engines_, multiply the area of water +piston, in inches, by the distance it travels, in inches, in a given +time. Deduct 3 per cent for slip and rod displacement. The product +divided by 231 gives the number of gallons in time named. + +_To find the velocity in feet per minute_ necessary to discharge a given +volume of water in a given time, multiply the number of cubic feet of +water by 144 and divide the product by the area of the pipe in inches. + +_To find the area of a required pipe_, the volume and velocity of water +being given, multiply the number of cubic feet of water by 144 and +divide the product by the velocity in feet per minute. The area being +found, the diameter can be learned by using any table giving the "area +of circles" and finding the nearest area, opposite to which will be +found the diameter to correspond. + + +Physical and Chemical Constants of Fixed Oils and Fats. + +(FROM LEWKOWITSCH AND OTHER AUTHORITIES.) + +______________________________________________________________________________ + | | | | | + | Specific |Specific | Melting- |Solidifying- | + | gravity | gravity | point. | point. | + | at 15°C. | at 100°C.| C. | C. | +_______________________|____________|__________|_____________|_______________| + | | | | | +Linseed oil | 0.931-0.938| 0.880 | -16° to -26°| -16° | +Hemp-seed oil | 0.925-0.931| | | -27° | +Walnut oil | 0.925-0.926| 0.871 | | -27° | +Poppy-seed oil | 0.924-0.927| 0.873 | | -18° | +Sunflower oil | 0.924-0.926| 0.919 | | -17° | +Fir-seed oil | 0.925-0.928| | | -27° to -30° | +Maize oil | 0.921-0.926| | | -10° to -15° | +Cotton-seed oil | 0.922-0.930| 0.867 | | 12° | +Sesame oil | 0.923-0.924| 0.871 | | -5° | +Rape-seed oil | 0.914-0.917| 0.863 | | -2° to -10° | +Black mustard oil | 0.916-0.920| | | -17.5° | +Croton oil | 0.942-0.955| | | -16° | +Castor oil | 0.960-0.966| 0.910 | | -12° to -18° | +Apricot-kernel oil | 0.915-0.919| | | -14° | +Almond oil | | 0.915-0.920| | | -10° to -20° | +Peanut (arachis) oil | 0.916-0.920| 0.867 | | -3° to -7° | +Olive oil | 0.914-0.917| 0.862 | | 2° | +Menhaden oil | 0.927-0.933| | | -4° | +Cod-liver oil | 0.922-0.927| 0.874 | | 0° to -10° | +Seal oil | 0.924-0.929| 0.873 | | 3° | +Whale oil | 0.920-0.930| 0.872 | | -2° | +Dolphin oil | 0.917-0.918| | | 5° to -3° | +Porpoise oil | 0.926 | 0.871 | | -16° | +Neat's-foot oil | 0.914-0.916| 0.861 | | 0° to 1.5° | +Cotton-seed stearine | 0.919-0.923| 0.867 | 40° | 31° to 32.5° | +Palm oil | 0.921-0.925| 0.856 | 27° to 42° | | +Cacao butter | 0.950-0.952| 0.858 | 30° to 33° | 25° to 26° | +Cocoa-nut oil | 0.925-0.926| 0.873 | 20° to 26° | 16° to 20° | +Myrtle wax | 0.995 | 0.875 | 40° to 44° | 39° to 43° | +Japan wax | 0.970-0.980| 0.875 | 51° to 54.5°| 46° | +Lard | 0.931-0.938| 0.861 | 41° to 46° | 29° | +Bone fat | 0.914-0.916| | 21° to 22° | 15° to 17° | +Tallow | 0.943-0.952| 0.860 | 42° to 46° | 35° to 37° | +Butter fat | 0.927-0.936| 0.866 | 29.5° to 33°| 19° to 20° | +Oleomargarine | 0.924-0.930| 0.859 | | | +Sperm oil | 0.875-0.884| 0.833 | | -25° | +Bottle-nose oil | 0.879-0.880| 0.827 | | | +Carnauba wax | 0.990-0.999| 0.842 | 84° to 85° | 80° to 81° | +Wool-fat | 0.973 | 0.901 | 39° to 42° | 30° to 30.2° | +Beeswax | 0.958-0.969| 0.822 | 62° to 64° | 60.5° to 62° | +Spermaceti | 0.960 | 0.812 | 43.5° to 49°| 43.4° to 44.2°| +Chinese wax | 0.970 | 0.810 | 80.5° to 81°| 80.5° to 81° | +Tung (Chinese wood oil)| 0.936-0.942| | | below -17° | +Soya-bean oil | 0.924-0.927| | | 8° to 15° | +_______________________|____________|__________|_____________|_______________| + + +Physical and Chemical Constants of Fixed Oils and Fats. + +(FROM LEWKOWITSCH AND OTHER AUTHORITIES.) + +Column Headings: +A: Saponification value. +B: Maumené test. +C: Iodine value. +D: Hehner value. +E: Reichert value. + +______________________________________________________________________________ + | | | | | | + | [A] | [B] | [C] | [D] | [E] | +___________________|_____________|_____________|____________|_________|______| + | | | | | | +Linseed oil | 190-195 | 104°-111° | 175-190 | | | +Hemp-seed oil | 190-193 | 95°-96° | 148 | | | +Walnut oil | 195 | 96°-101° | 144-147 | | | +Poppy-seed oil | 195 | 86°-88° | 134-141 | 95.38 | | +Sunflower oil | 193-194 | 72°-75° | 120-129 | 95 | | +Fir-seed oil | 191.3 | 98°-99° | 118.9-120 | | | +Maize oil | 188-193 | 56°-60.5° | 117-125 | 89-95.7 | 2.5 | +Cotton-seed oil | 191-195 | 68°-77° | 104-110 | 96-17 | | +Sesame oil | 189-193 | 64°-68° | 105-109 | 95.8 | 0.35 | +Rape-seed oil | 170-178 | 51°-60° | 95-105 | 95 | | +Black mustard oil | 174-174.6 | 43°-44° | 96-110 | 95.05 | | +Croton oil | 210.3-215 | | 101.7-104 | 89 | 13.5 | +Castor oil | 178-186 | 46°-47° | 83.4-85.9 | | 1.4 | +Apricot-kernel oil | 192.2-193.1 | 42.5°-46° | 100-107 | | | +Almond oil | 190.5-195.4 | 51°-54° | 93-97 | 96.2 | | +Peanut (arachis) | | | | | | + oil | 190-197 | 45°-49° | 85-98 | 95.86 | | +Olive oil | 191-196 | 41.5°-45.5° | 80.6-84.5 | 95.43 | 0.3 | +Menhaden oil | 189.3-192 | 123°-128° | 140-170 | | 1.2 | +Cod-liver oil | 182-187 | 102°-103° | 154-180 | 95.3 | | +Seal oil | 190-196 | 92° | 127-140 | 94.2 | 0.22 | +Whale-oil | 188-193 | 91°-92° | 110-136 | 93.5 | 2.04 | +Dolphin {Body oil | 197.3 | | 99.5 | 93.07 | 5.6 | + oil {Jaw oil | 200 | | 32.8 | 66.28 |65.92 | +Porpoise {Body oil | 216-218.8 | 50° | 119.4 | |23.45 | + oil {Jaw oil | 253.7 | | 49.6 | 68.41 |65.8 | +Neat's-foot oil | 194.3 | 47°-48.5° | 69.3-70.4 | | | +Cotton-seed | | | | | | + stearine. | 194.6-195.1 | 48° | 88.7-92.8 | 96.3 | | +Palm oil | 196.3-202 | | 53-57 | 95.6 | 0.5 | +Cacao butter | 192.2-193.5 | | 32-41 | 94.59 | 1.6 | +Cocoa-nut oil | 250-253 | | 8.5-9.3 | 88.6 | 3.7 | +Myrtle wax | 205.7-211.7 | | 2.9 | | | +Japan wax | 220-222.4 | | 4.2-8.5 | 90.6 | | +Lard | 195.3-196.6 | 27°-32° | 57-70 | 96 | | +Bone fat | 190.9 | | 46.3-49.6 | | | +Tallow | 195-198 | | 36-47 | 95.6 | 0.25 | +Butter fat | 221.5-227 | | 26-35 | 87.5 |28.78 | +Oleomargarine | 194-203.7 | | 55.3-60 | 95-96 | 2.6 | +Sperm oil | 132.5-147 | 47°-51° | 84 | | 1.3 | +Bottle-nose oil | 126-134 | 41°-47° | 77.4-82 | | 1.4 | +Carnauba wax | 80-84 | | 13.5 | | | +Wool-fat | 98.2-102.4 | | 25-28 | | | +Beeswax | 91-96 | | 8.3-11 | | | +Spermaceti | 128 | | | | | +Chinese wax | 63 | | | | | +Tung (Chinese | | | | | | + wood oil) | 193 | | 150-165 | | | +Soya-bean oil | 190.6-192.9 | 59°-61° | 121.3-124 | 95.5 | | +___________________|_____________|_____________|____________|_________|______| + + +*Temperature Correction Table for Hehner's Concentrated Bichromate +Solution for Glycerine Analysis + +__________________________________________ + | | + A | f | +Temperature | Corrected Volume | Logarithm + | 1 c.c. | +____________|__________________|__________ + | | + 11° C | 0.9980 ccm | 99913 + 12° " | 0.9985 " | 99935 + 13° " | 0.9990 " | 99956 + 14° " | 0.9995 " | 99978 + 15° " | 1.0000 " | 00000 + 16° " | 1.0005 " | 00022 + 17° " | 1.0010 " | 00043 + 18° " | 1.0015 " | 00065 + 19° " | 1.0020 " | 00087 + 20° " | 1.0025 " | 00108 + 21° " | 1.0030 " | 00130 + 22° " | 1.0035 " | 00152 + 23° " | 1.0040 " | 00173 +____________|__________________|__________ + + +*Table of Important Fatty Acids + +_______________________________________________________________________________ + | | | | | + | | | Boiling Point | | + | | |______________________| |Neutral- + | | Mol. | | | Melt- |ization + Name | Formula | Wt. | Ordinary | 100 mm | ing |value + | | | Pressure | Pressure | Pt. | Mg. KOH +___________|___________________|______|__________|___________|_______|__________ + | | | | | | +Butyric | C_{4}H_{8}O_{2} | 88 | 162.3 | | |637.5 +Caproic | C_{6}H_{12}O_{2} | 116 | 199.7 | | |483.6 +Caprylic | C_{8}H_{16}O_{2} | 144 | 236-237 | | 16.5 |389.6 +Capric | C_{10}H_{20}O_{2} | 172 | 268-270 | 199.5-200 | 31.3 |326.2 +Lauric | C_{12}H_{24}O_{2} | 200 | | 225 | 43.6 |280.5 +Myristic | C_{14}H_{28}O_{2} | 228 | | 250.5 | 53.8 |246.1 +Palmitic | C_{16}H_{32}O_{2} | 256 | | 268.5 | 62 |219.1 +Stearic | C_{18}H_{36}O_{2} | 284 | | 291 | 69.2 |197.5 +Arachidic | C_{20}H_{40}O_{2} | 302 | | | 75 |185.8 +Behenic | C_{22}H_{44}O_{2} | 330 | | | 77-78 |170.0 +Cerotic | C_{27}H_{54}O_{2} | 400 | | | 78 |140.25 +Melissic | C_{30}H_{60}O_{2} | 442 | | | 90 |126.5 +Oleic | C_{18}H_{34}O_{2} | 282 | | 185.5-286 | 14 |198.9 +Erucic | C_{22}H_{42}O_{2} | 338 | | | 33-34 |165.9 +Linolic | C_{18}H_{32}O_{2} | 280 | | | |200.4 +Linolenic | C_{18}H_{30}O_{2} | 278 | | | |201.5 +Ricinoleic | C_{18}H_{34}O_{3} | 298 | | | |181.6 +___________|___________________|______|__________|___________|_______|__________ + + +*Comparison of Thermometer Scales + +n Degree Celsius = 4/5n Degree Reaumur = 32 + 9/5n Degree Fahrenheit + +n Degree Reaumur = 5/4n Degree Celsius = 32 + 9/4n Degree Fahrenheit + +n Degree Fahrenheit = 5/9 (n - 32) Degree Celsius = 4/9 (n - 32) Deg. R + +============================================================================= + C. R. F. | C. R. F. | C. R. F. | C. R. F. +--------------------|------------------|------------------|------------------ +-20 -16 -4 | 20 16 68 | 60 48 140 | 100 80 212 +-19 -15.2 -2.2 | 21 16.8 69.8 | 61 48.8 141.8 | 101 80.8 213.8 +-18 -14.4 -0.4 | 22 17.6 71.6 | 62 49.6 143.6 | 102 81.6 215.6 +-17 -13.6 1.4 | 23 18.4 73.4 | 63 50.4 145.4 | 103 82.4 217.4 +-16 -12.8 3.2 | 24 19.2 75.2 | 64 51.2 147.2 | 104 83.2 219.2| + | | | +-15 -12 5 | 25 20 77 | 65 52 149 | 105 84 221 +-14 -11.2 6.8 | 26 20.8 78.8 | 66 52.8 150.8 | 106 84.8 222.8 +-13 -10.4 8.6 | 27 21.6 80.6 | 67 53.6 152.6 | 107 85.6 224.6 +-12 -9.6 10.4 | 28 22.4 82.4 | 68 54.4 154.4 | 108 86.4 226.4 +-11 -8.8 12.2 | 29 23.2 84.2 | 69 55.2 156.2 | 109 87.2 228.2 + | | | +-10 -8 14 | 30 24 86 | 70 56 158 | 110 88 230 + -9 -7.2 15.8 | 31 24.8 87.8 | 71 56.8 159.8 | 111 88.8 231.8 + -8 -6.4 17.6 | 32 25.6 89.6 | 72 57.6 161.6 | 112 89.6 233.6 + -7 -5.6 19.4 | 33 26.4 91.4 | 73 58.4 163.4 | 113 90.4 235.4 + -6 -4.8 21.2 | 34 27.2 93.2 | 74 59.2 165.2 | 114 91.2 237.2 + | | | + -5 -4 23 | 35 28 95 | 75 60 167 | 115 92 239 + -4 -3.2 24.8 | 36 28.8 96.8 | 76 60.8 168.8 | 116 92.8 240.8 + -3 -2.4 26.6 | 37 29.6 98.6 | 77 61.6 170.6 | 117 93.6 242.6 + -2 -1.6 28.4 | 38 30.4 100.4 | 78 62.4 172.4 | 118 94.4 244.4 + -1 -0.8 30.2 | 39 31.2 102.2 | 79 63.2 174.2 | 119 95.2 246.2 + | | | + 0 0 32 | 40 32 104 | 80 64 176 | 120 96 248 + 1 0.8 33.8 | 41 32.8 105.8 | 81 64.8 177.8 | 121 96.8 249.8 + 2 1.6 35.6 | 42 33.6 107.6 | 82 65.6 179.6 | 122 97.6 252.6 + 3 2.4 37.4 | 43 34.4 109.4 | 83 66.4 181.4 | 123 98.4 253.4 + 4 3.2 39.2 | 44 35.2 111.2 | 84 67.2 183.2 | 124 99.2 255.2 + | | | + 5 4 41 | 45 36 113 | 85 68 185 | 125 100 257 + 6 4.8 42.8 | 46 36.8 114.8 | 86 68.8 186.8 | 126 100.8 258.8 + 7 5.6 44.6 | 47 37.6 116.6 | 87 69.6 188.6 | 127 101.6 260.6 + 8 6.4 46.4 | 48 38.4 118.4 | 88 70.4 190.4 | 128 102.4 262.4 + 9 7.2 48.2 | 49 39.2 120.2 | 89 71.2 192.2 | 129 103.2 264.2 + | | | + 10 8 50 | 50 40 122 | 90 72 194 | 130 104 266 + 11 8.8 51.8 | 51 40.8 123.8 | 91 72.8 195.8 | 131 104.8 267.8 + 12 9.6 53.6 | 52 41.6 125.6 | 92 73.6 197.6 | 132 105.6 269.6 + 13 10.4 55.4 | 53 42.4 127.4 | 93 74.4 199.4 | 133 106.4 271.4 + 14 11.2 57.2 | 54 43.2 129.2 | 94 75.2 201.2 | 134 107.2 273.2 + | | | + 15 12 59 | 55 44 131 | 95 76 203 | 135 108 275 + 16 12.8 60.8 | 56 44.8 132.8 | 96 76.8 204.8 | 136 108.8 276.8 + 17 13.6 62.6 | 57 45.6 134.6 | 97 77.6 206.6 | 137 109.6 278.6 + 18 14.4 64.4 | 58 46.4 136.4 | 98 78.4 208.4 | 138 110.4 280.4 + 19 15.2 66.2 | 59 47.2 138.2 | 99 79.2 210.2 | 139 111.2 282.2 +=============================================================================== + + +*Quantities of Alkali Required for Saponification of Fats of Average +Molecular Weight 670 + +(Cocoanut Oil, Palmkernel Oil) + +_________________________________________________ + | | | + | Liters Alkali | Liters Alkali | + | Solution | Solution | +Kilos | Sp. Gr. 1.1 | Sp. Gr. 1.2 | +______|_____________________|___________________| + | | | | | + | NaOH | KOH | NaOH | KOH | +______|__________|__________|_________|_________| + | | | | | + 1000 | 1875.83 | 1902.99 | 844.67 | 930.35 | + 2000 | 3751.66 | 3805.97 | 1689.35 | 1860.70 | + 3000 | 5627.50 | 5708.96 | 2534.02 | 2791.04 | + 4000 | 7508.33 | 7611.94 | 3378.69 | 3721.39 | + 5000 | 9379.16 | 9514.93 | 4223.37 | 4651.74 | + 6000 | 11254.99 | 11417.91 | 5068.04 | 5582.09 | + 7000 | 13130.82 | 13320.90 | 5912.71 | 6512.44 | + 8000 | 15006.66 | 15223.88 | 6757.38 | 7442.78 | + 9000 | 16882.49 | 17126.87 | 7602.06 | 8373.13 | +10000 | 18758.32 | 19029.85 | 8446.73 | 9303.48 | +______|__________|__________|_________|_________| + +______________________________________________ + | | + | Liters Alkali | Liters Alkali + | Solution | Solution +Kilos | Sp. Gr. 1.3 | Sp. Gr. 1.355 +______|___________________|___________________ + | | | | + | NaOH | KOH | NaOH | KOH +______|_________|_________|_________|_________ + | | | | + 1000 | 510.27 | 622.71 | 409.61 | 517.97 + 2000 | 1020.54 | 1245.41 | 819.21 | 1035.95 + 3000 | 1530.81 | 1868.12 | 1228.82 | 1553.92 + 4000 | 2041.01 | 2490.83 | 1638.43 | 2071.90 + 5000 | 2551.35 | 3113.54 | 2048.04 | 2589.87 + 6000 | 3061.61 | 3736.24 | 2457.65 | 3107.84 + 7000 | 3571.88 | 4358.95 | 2867.26 | 3625.82 + 8000 | 4082.15 | 4981.66 | 3276.86 | 4143.79 + 9000 | 4592.42 | 5604.36 | 3886.47 | 4661.77 +10000 | 5102.69 | 6227.02 | 4096.08 | 5179.74 +______|_________|_________|_________|_________ + + +*Quantities of Alkali Required for Saponification of Fats of Average +Molecular Weight 860 + +(Tallow, Cottonseed Oil, Olive Oil, Etc.) + +_________________________________________________ + | | | + | Liters Alkali | Liters Alkali | + | Solution | Solution | +Kilos | Sp. Gr. 1.1 | Sp. Gr. 1.2 | +______|_____________________|___________________| + | | | | | + | NaOH | KOH | NaOH | KOH | +______|__________|__________|_________|_________| + | | | | | + 1000 | 1461.40 | 1482.56 | 658.05 | 724.81 | + 2000 | 2922.81 | 2965.12 | 1316.12 | 1449.61 | + 3000 | 4384.21 | 4447.67 | 1974.18 | 2174.42 | + 4000 | 5845.62 | 5930.23 | 2632.24 | 2899.22 | + 5000 | 7307.02 | 7412.79 | 3290.80 | 3624.03 | + 6000 | 8768.42 | 8895.85 | 3948.35 | 4348.84 | + 7000 | 10229.83 | 10377.91 | 4606.41 | 5073.64 | + 8000 | 11691.23 | 11860.45 | 5264.47 | 5798.45 | + 9000 | 13152.64 | 13343.02 | 5922.53 | 6523.25 | +10000 | 14614.04 | 14825.58 | 6580.59 | 7248.06 | +______|__________|__________|_________|_________| +______________________________________________ + | | + | Liters Alkali | Liters Alkali + | Solution | Solution +Kilos | Sp. Gr. 1.3 | Sp. Gr. 1.355 +______|___________________|___________________ + | | | | + | NaOH | KOH | NaOH | KOH +______|_________|_________|_________|_________ + | | | | + 1000 | 397.54 | 485.13 | 319.11 | 403.54 + 2000 | 795.07 | 970.27 | 638.23 | 807.08 + 3000 | 1192.61 | 1455.40 | 957.34 | 1210.61 + 4000 | 1590.14 | 1940.53 | 1276.45 | 1614.15 + 5000 | 1987.68 | 2425.67 | 1595.57 | 2017.69 + 6000 | 2385.21 | 2910.80 | 1914.68 | 2421.23 + 7000 | 2782.75 | 3395.93 | 2233.79 | 2824.77 + 8000 | 3180.28 | 3881.06 | 2552.90 | 3228.30 + 9000 | 3577.82 | 4366.20 | 2872.02 | 3631.84 +10000 | 3975.35 | 4851.33 | 3191.13 | 4035.38 +______|_________|_________|_________|_________ + + +DENSITY AND STRENGTH OF SULPHURIC ACID (SIDERSKY). + +Column Headings: +A: Degrees Twaddell +B: Sp. Gr. at 15° C. +C: % of pure acid (H_{2}SO_{4}). +D: Equivalent (in cc.) of a kilo of pure acid. +E: Equivalent (in cc.) of a liter of pure acid. + + +========================================= + + [A] [B] [C] [D] [E] +_________________________________________ + +1 1.007 1.9 52.620 96.930 +3 1.014 2.8 35.710 66.450 +4 1.022 3.8 25.650 47.230 +6 1.029 4.8 20.410 37.582 +8 1.037 5.8 16.670 30.690 +9 1.045 6.8 14.085 25.938 +10 1.052 7.8 12.198 22.460 +12 1.062 8.8 10.755 19.803 +13 1.067 9.8 9.524 17.540 +15 1.075 10.9 8.547 15.740 +17 1.083 11.9 7.752 14.278 +18 1.091 13.0 7.042 12.969 +20 1.100 14.1 6.452 11.882 +22 1.108 15.2 5.953 10.962 +23 1.116 16.2 5.526 10.177 +25 1.125 17.3 5.405 9.954 +27 1.134 18.5 4.76 8.770 +29 1.142 19.6 4.465 8.223 +30 1.152 20.8 4.184 7.723 +32 1.162 22.2 3.876 7.138 +34 1.171 23.3 3.663 6.745 +36 1.180 24.5 3.541 6.521 +38 1.190 25.8 3.258 5.999 +40 1.200 27.1 3.077 5.666 +42 1.210 28.4 2.907 5.353 +44 1.220 29.6 2.770 5.102 +46 1.231 31.0 2.618 4.865 +48 1.241 32.2 2.500 4.604 +50 1.252 33.4 2.392 4.406 +53 1.263 34.7 2.283 4.205 +55 1.274 36.0 2.179 4.012 +57 1.285 37.4 2.079 3.829 +60 1.297 38.8 1.988 3.661 +62 1.308 40.2 1.905 3.508 +64 1.320 41.6 1.821 3.354 +66 1.332 43.0 1.745 3.214 +69 1.345 44.4 1.665 3.085 +71 1.357 45.5 1.621 2.985 +74 1.370 46.9 1.558 2.869 +77 1.383 48.3 1.497 2.757 +80 1.397 49.8 1.436 2.646 +82 1.410 51.2 1.386 2.551 +85 1.424 52.6 1.335 2.459 +88 1.438 54.0 1.287 2.370 +91 1.453 55.4 1.237 2.270 +94 1.468 56.9 1.195 2.200 +97 1.483 58.3 1.156 2.130 +100 1.498 59.6 1.116 2.050 +103 1.514 61.0 1.080 1.980 +106 1.530 62.5 1.045 1.930 +108 1.540 64.0 1.010 1.860 +113 1.563 65.5 0.975 1.800 +116 1.580 67.0 0.950 1.740 +120 1.597 68.6 0.917 1.690 +123 1.615 70.0 0.888 1.630 +127 1.634 71.6 0.855 1.570 +130 1.652 73.2 0.845 1.520 +134 1.671 74.7 0.800 1.470 +138 1.691 76.4 0.774 1.430 +142 1.711 78.1 0.749 1.390 +146 1.732 79.9 0.722 1.320 +151 1.753 81.7 0.705 1.280 +155 1.774 84.1 0.672 1.235 +160 1.798 86.5 0.639 1.190 +164 1.819 89.7 0.609 1.120 +168 1.842 100.0 0.544 1.000 + + +*Densities of Potassium Carbonate Solutions at 15 C (Gerlach) + +======================= + | | + | Per cent | +Sp. Gr. | of pure | + | K_{2}CO_{3} | +________|_____________| + | | +1.00914 | 1 | +1.01829 | 2 | +1.02743 | 3 | +1.03658 | 4 | +1.04572 | 5 | +1.05513 | 6 | +1.06454 | 7 | +1.07396 | 8 | +1.08337 | 9 | +1.09278 | 10 | +1.10258 | 11 | +1.11238 | 12 | +1.12219 | 13 | +1.13199 | 14 | +1.14179 | 15 | +1.15200 | 16 | +1.16222 | 17 | +1.17243 | 18 | +1.18265 | 19 | +1.19286 | 20 | +1.20344 | 21 | +1.21402 | 22 | +1.22459 | 23 | +1.23517 | 24 | +1.24575 | 25 | +1.25681 | 26 | +1.26787 | 27 | +1.27893 | 28 | +1.28999 | 29 | +1.30105 | 30 | +1.31261 | 31 | +1.32417 | 32 | +1.33573 | 33 | +1.34729 | 34 | +1.35885 | 35 | +1.37082 | 36 | +1.38279 | 37 | +1.39476 | 38 | +1.40673 | 39 | +1.41870 | 40 | +1.43104 | 41 | +1.44338 | 42 | +1.45573 | 43 | +1.46807 | 44 | +1.48041 | 45 | +1.49314 | 46 | +1.50588 | 47 | +1.51861 | 48 | +1.53135 | 49 | +1.54408 | 50 | +1.55728 | 51 | +1.57048 | 52 | +1.57079 | 53.024 | +________|_____________| + + +*Constants of Certain Fatty Acids and Triglycerides + +========================================================= + | | | + | | | Per cent Yield +Triglycerides | Mol. Wt. | Mol. Wt. |__________________ + of | of Fatty | of Tri- | | + | of Fatty | glycerides | Fatty | Glycerine + | | | Acid | +______________|__________|____________|_______|___________ + | | | | +Stearic Acid | 284 | 890 | 95.73 | 10.34 +Oleic Acid | 282 | 884 | 95.70 | 10.41 +Margaric Acid | 270 | 848 | 95.52 | 10.85 +Palmitic Acid | 256 | 806 | 95.28 | 11.42 +Myristic Acid | 228 | 722 | 94.47 | 12.74 +Lauric Acid | 200 | 638 | 94.04 | 14.42 +Capric Acid | 172 | 594 | 93.14 | 15.48 +Caproic Acid | 116 | 386 | 90.16 | 23.83 +Butyric Acid | 88 | 302 | 87.41 | 30.46 +______________|__________|____________|_______|___________ + + +PERCENTAGES OF SOLID CAUSTIC SODA AND CAUSTIC POTASH IN CAUSTIC LYES +ACCORDING TO BAUME SCALE. + +Degrees % % + Baumé. NaOH KOH + + 1 0.61 0.90 + 2 0.93 1.70 + 3 2.00 2.60 + 4 2.71 3.50 + 5 3.35 4.50 + 6 4.00 5.60 + 7 4.556 6.286 + 8 5.29 7.40 + 9 5.87 8.20 +10 6.55 9.20 +11 7.31 10.10 +12 8.00 10.90 +13 8.68 12.00 +14 9.42 12.90 +15 10.06 13.80 +16 10.97 14.80 +17 11.84 15.70 +18 12.64 16.50 +19 13.55 17.60 +20 14.37 18.60 +21 15.13 19.50 +22 15.91 20.50 +23 16.77 21.40 +24 17.67 22.50 +25 18.58 23.30 +26 19.58 24.20 +27 20.59 25.10 +28 21.42 26.10 +29 22.64 27.00 +30 23.67 28.00 +31 24.81 28.90 +32 25.80 29.80 +33 26.83 30.70 +34 27.80 31.80 +35 28.83 32.70 +36 29.93 33.70 +37 31.22 34.90 +38 32.47 35.90 +39 33.69 36.90 +40 34.96 37.80 +41 36.25 38.90 +42 37.53 39.90 +43 38.80 40.90 +44 39.99 42.10 +45 41.41 43.40 +46 42.83 44.60 +47 44.38 45.80 +48 46.15 47.10 +49 47.58 48.25 +50 49.02 49.40 + + +GLYCERINE CONTENT OF MORE COMMON OILS AND FATS USED IN SOAP MAKING. + + Kind. Theoretical Average Free % Pure Yield + Yield of Pure Fatty Acid in Glycerine Soap Lye + Glycerine of Commercial in Commercial 80% Crude + Neutral Oil Oil. Oil. Glycerine. + or Fat. + +Beef Tallow 10.7 5 10.2 12.75 +Bone Grease 10.5 20-50 5.2- 8.4 6.5-10.5 +Castor Oil 9.8 0.5-10 8.8- 9.8 11.0-12.45 +Cocoanut Oil 13.9 3-5 13.2-13.5 16.5-16.9 +Cocoanut Oil Off 15-40 8.3-11.8 10.37-14.75 +Corn Oil 10.4 1-10 9.3-10.3 11.62-12.9 +Cottonseed Oil 10.6 Trace 10.6 13.25 +Hog Grease 10.6 0.5-1 10.5-10.6 13.12-13.25 +Horse Grease 10.6 1-3 10.5-10.6 13.12-13.25 +Olive Oil 10.3 2-25 7.7-10.2 9.62-12.75 +Olive Foots 30-60 4-7 5-8.75 +Palm Oil 11.0 10-50 5.5-10 6.87-12.5 +Palmkernel Oil 13.3 4-8 12.2-12.8 15.25-16 +Peanut Oil 10.4 5-20 8.3-9.9 10.37-12.37 +Soya Bean Oil 10.4 2 10.2 12.75 +Train Oil 10.0 2-20 8-9.8 10.0-12.25 +Vegetable Tallow 10.9 1-3 10.5-10.8 13.12-13.5 + + +*Table of Specific Gravities of Pure Commercial Glycerine with +Corresponding Percentage of Water. Temperature 15 C. + +------------------+------------------ + Sp. Gr. % Water | Sp. Gr. % Water + 1.262 0 | 1.160 38 + 1.261 1 | 1.157 39 + 1.258 2 | 1.155 40 + 1.255 3 | 1.152 41 + 1.2515 4 | 1.149 42 + 1.250 5 | 1.1464 43 + 1.2467 6 | 1.1437 44 + 1.2450 7 | 1.141 45 + 1.243 8 | 1.1377 46 + 1.241 9 | 1.1353 47 + 1.237 10 | 1.1326 48 + 1.235 11 | 1.1304 49 + 1.2324 12 | 1.127 50 + 1.229 13 | 1.125 51 + 1.2265 14 | 1.1224 52 + 1.2245 15 | 1.1204 53 + 1.2225 16 | 1.117 54 + 1.2185 17 | 1.114 55 + 1.2174 18 | 1.112 56 + 1.2142 19 | 1.109 57 + 1.211 20 | 1.106 58 + 1.207 21 | 1.103 59 + 1.203 22 | 1.1006 60 + 1.2004 23 | 1.088 65 + 1.198 24 | 1.075 70 + 1.195 25 | 1.0623 75 + 1.1923 26 | 1.049 80 + 1.189 27 | 1.0365 85 + 1.188 28 | 1.0243 90 + 1.1846 29 | 1.0218 91 + 1.182 30 | 1.0192 92 + 1.179 31 | 1.0168 93 + 1.176 32 | 1.0147 94 + 1.1734 33 | 1.0125 95 + 1.171 34 | 1.01 96 + 1.168 35 | 1.0074 97 + 1.165 36 | 1.0053 98 + 1.163 37 | 1.0026 99 +------------------+------------------ + + +Table of Percentage, Specific Gravity and Beaume Degree of Pure +Glycerine Solutions + +=========+===========+===========++=========+===========+=========== +Per cent |Sp. Gr. |Degree ||Per cent |Sp. Gr. |Degree +Water |Champion |Beaume ||Water |Champion |Beaume + |and Pellet |(Berthelot)|| |and Pellet |(Berthelot) +=========+===========+===========++=========+===========+=========== + 0 | 1.2640 | 31.2 || 11.0 | 1.2350 | 28.6 + 0.5 | 1.2625 | 31.0 || 11.5 | 1.2335 | 28.4 + 1.0 | 1.2612 | 30.9 || 12.0 | 1.2322 | 28.3 + 1.5 | 1.2600 | 30.8 || 12.5 | 1.2307 | 28.2 + 2.0 | 1.2585 | 30.7 || 13.0 | 1.2295 | 28.0 + 2.5 | 1.2575 | 30.6 || 13.5 | 1.2280 | 27.8 + 3.0 | 1.2560 | 30.4 || 14.0 | 1.2270 | 27.7 + 3.5 | 1.2545 | 30.3 || 14.5 | 1.2255 | 27.6 + 4.0 | 1.2532 | 30.2 || 15.0 | 1.2242 | 27.4 + 4.5 | 1.2520 | 30.1 || 15.5 | 1.2230 | 27.3 + 5.0 | 1.2505 | 30.0 || 16.0 | 1.2217 | 27.2 + 5.5 | 1.2490 | 29.9 || 16.5 | 1.2202 | 27.0 + 6.0 | 1.2480 | 29.8 || 17.0 | 1.2190 | 26.9 + 6.5 | 1.2465 | 29.7 || 17.5 | 1.2177 | 26.8 + 7.0 | 1.2455 | 29.6 || 18.0 | 1.2165 | 26.7 + 7.5 | 1.2440 | 29.5 || 18.5 | 1.2150 | 26.5 + 8.0 | 1.2427 | 29.3 || 19.0 | 1.2137 | 26.4 + 8.5 | 1.2412 | 29.2 || 19.5 | 1.2125 | 26.3 + 9.0 | 1.2400 | 29.0 || 20.0 | 1.2112 | 26.2 + 9.5 | 1.2390 | 28.9 || 20.5 | 1.2100 | 26.0 + 10.0 | 1.2375 | 28.8 || 21.0 | 1.2085 | 25.0 + 10.5 | 1.2362 | 28.7 || | | +=========+===========+===========++=========+===========+=========== + + +*Table of Specific Gravities of Pure Glycerine Solutions with +Corresponding Beaume Degree and Percent Water + +--------+--------+-------+---------+--------+-------- +Per cent| Sp. Gr.| Degree| Percent | Sp. Gr.| Degree +Water | | Beaume| Water | | Beaume +--------+--------+-------+---------+--------+-------- + | | | | | + 0.0 | 1.2640 | 31.2 | 1.0 | 1.2612 | 30.9 + 0.5 | 1.2625 | 31.0 | 1.5 | 1.2600 | 30.8 + 2.0 | 1.2585 | 30.7 | 12.0 | 1.2322 | 28.3 + 2.5 | 1.2575 | 30.6 | 12.5 | 1.2307 | 28.2 + 3.0 | 1.2560 | 30.4 | 13.0 | 1.2295 | 28.0 + 3.5 | 1.2545 | 30.3 | 13.5 | 1.2280 | 27.8 + 4.0 | 1.2532 | 30.2 | 14.0 | 1.2270 | 27.7 + 4.5 | 1.2520 | 30.1 | 14.5 | 1.2255 | 27.6 + 5.0 | 1.2505 | 30.0 | 15.0 | 1.2242 | 27.4 + 5.5 | 1.2490 | 29.9 | 15.5 | 1.2230 | 27.3 + 6.0 | 1.2480 | 29.8 | 16.0 | 1.2217 | 27.2 + 6.5 | 1.2465 | 29.7 | 16.5 | 1.2202 | 27.0 + 7.0 | 1.2455 | 29.6 | 17.0 | 1.2190 | 26.9 + 7.5 | 1.2440 | 29.5 | 17.5 | 1.2177 | 26.8 + 8.0 | 1.2427 | 29.3 | 18.0 | 1.2165 | 26.7 + 8.5 | 1.2412 | 29.2 | 18.5 | 1.2150 | 26.5 + 9.0 | 1.2400 | 29.0 | 19.0 | 1.2137 | 26.4 + 9.5 | 1.2390 | 28.9 | 19.5 | 1.2125 | 26.3 + 10.0 | 1.2375 | 28.8 | 20.0 | 1.2112 | 26.2 + 10.5 | 1.2362 | 28.7 | 20.5 | 1.2100 | 26.0 + 11.0 | 1.2350 | 28.6 | 21.0 | 1.2085 | 25.9 + 11.5 | 1.2335 | 28.4 | | | +--------+--------+-------+---------+--------+-------- + + + + +INDEX + + +A + +Acetin process for the determination of glycerol, 155. + +Acid, Clupanodonic, 20. + +Acid, Hydrochloric, 111. + +Acid, Lauric, 2. + +Acid, Myristic, 2. + +Acid, Napthenic, 24. + +Acid, Oleic, 15, 19. + +Acid, Palmitic, 2. + +Acid, Pinic, 22. + +Acid, Resin, 144. + +Acid, Stearic, 15, 19. + +Acid, Sulfuric, 112. + +Acid, Sylvic, 22. + +Acid saponification, 120. + +Air bleaching of palm oil, 12. + +Albuminous matter, Removal from tallow, 6. + +Alcohol, Denatured, 82. + +Alcoholic method for free alkali in soap, 139. + +Alkali Blue 6 B, indicator, 129. + +Alkali, Total, determination of in soap, 147. + +Alkalis, 25. + +Alkalis used in soap making, + Testing of, 134. + +Amalgamator, 33. + +Analysis, Glycerine, International, 150. + +Analysis, Soap, 137. + +Analysis, Standard methods for fats and oils, 165-196. + +Aqueous saponification, 121. + +Arachis oil, 79. + +Autoclave saponification, 118. + +Automobile soaps, 41. + + +B + +Barrels, sampling, 168. + +Baumé scale, 25. + +Bayberry wax, Use in shaving soap, 89. + +Bichromate Process for glycerol determination, 160. + +Bleaching, Fullers' earth process for tallow, 4. + +Bleaching palm oil by bichromate method, 9. + +Bleaching palm oil by air, 12. + +Bosshard & Huggenberg method for determination of free alkali, 140. + +Bunching of soap, 52. + + +C + +Candelite, 96. + +Candle tar, 125. + +Carbolic soap, 77. + +Carbon Dioxide, Formation of in carbonate saponification, 45. + +Carbonate, potassium, 29. + +Carbonate, saponification, 35, 45. + +Carbonate, sodium, 28. + +Castile soap, 79. + +Castor oil ferment, 121. + +Castor oil, Use of in transparent soaps, 83. + +Caustic potash, 26. + +Caustic potash, Electrolytic, 27. + +Caustic soda, 26. + +Changes in soap-making, 36. + +Chemist, Importance of, 127. + +Chipper, Soap, 32. + +Chip soap, 54. + +Chip soap, Cold made, 55. + +Chip soap, Unfilled, 56. + +Chrome bleaching of palm oil, 9. + +Cloud test for oil, Standard method, 182-183. + +Clupanodonic acid, 20. + +Cocoanut oil, 6. + +Cold cream soap, 78. + +Cold made chip soaps, 55. + +Cold made toilet soaps, 72. + +Cold made transparent soaps, 84. + +Cold process, 35, 43. + +Colophony, 22. + +Coloring soap, 75. + +Copra, 7. + +Corn oil, 14. + +Corrosive sublimate, 78. + +Cotton goods. Soaps used for, 103. + +Cottonseed oil, 14. + +Cream, Shaving, 90. + +Crude glycerine, 113. + +Crutcher, 32. + +Curd soap, 71. + +Cutting table, 32. + + +D + +Determination of free fatty acid, 128. + +Determination of unsaponifiable matter, 132. + +Distillation of fatty acids, 125. + +Drying machine, 32. + + +E + +Enzymes, 17. + +Eschweger soap, 81. + +Examination of fats and oils, 128. + + +F + +Fahrion's method for moisture, 138. + +Fats and oils, Examination of, 128. + +Fats and oils used in soap manufacture, 3. + +Fatty acids, 14. + +Fatty acids, Distillation of, 125. + +Ferments, Splitting fats with, 121. + +Fillers for laundry soaps, 53. + +Fillers for soap powders, 58. + +Finishing change, 36. + +Fish oils, 20. + +Floating soap, 62. + +Formaldehyde soap, 78. + +Frames, 31. + +Free alkali in soap, Determination of, 139. + +Free fatty acid, Determination of, 128. + +Free fatty acids, Extraction from tallow, 6. + +Free fatty acid, Standard method of dilu., 174. + Note on method, 188-189. + +Full boiled soaps, 35. + +Fullers' earth bleaching of tallow, 4. + + +G + +Glycerides, 2. + +Glycerine, 2. + +Glycerine analysis, 150. + +Glycerine change, 36. + +Glycerine, Crude, 113. + +Glycerine in spent lyes, Recovery of, 106. + +Glycerine in soap, Determination of, 149. + +Glycerine, Sampling crude, 162. + +Glycerine soaps, 83. + +Glycerol content, Ways of calculating actual, 159. + +Glycerol determination, Acetin process, 155. + +Glycerol determination, Bichromate process for, 160. + +Graining soap, 30. + +Grease, 21. + +Grease, Bleaching, 21. + +Grinding soap, 34. + + +H + +Hand Paste, 93. + +Hard water, 29. + +Hardened oils in toilet soap, Use of, 96. + +Hydrocarbon oils, 2. + +Hydrogenating oils, 19. + +Hydrolysis of fats and oils, 17. + +Hydrolytic dissociation of soap, 1. + +Hydrometers, 25. + + +I + +Indicators, Action, 135-6. + +Insoluble impurities in fatty oils, Determination of (standard method), 172. + Note on method, 187. + +Insoluble matter in soap, determination of, 143. + +International committee on glycerine analysis, 150. + +Iodine manufacturing oil, 191. + +Iodine member Wijs method, Standard, 177-181. + Note on method, 191. + +Iodine soap, 78. + + +J + +Joslin, ref., 113. + + +K + +"Killing" change, 36. + +Koettstorfer number (Standard method), 181-182. + +Kontakt reagent, 117. + +Krebitz Process, 123. + +Krutolin, 96. + + +L + +Leiste & Stiepel method for rosin in soap, 146. + +Liebermann, Storch reaction, 144. + +Light powders, 60. + +Laundry soap, 48. + +LeBlanc Process, 28. + +Lewkowitsch, ref., 17, 146. + +Lime saponification, 118. + +Lime, Use in Krebitz Process, 123. + +Lime, Use in treatment of glycerine water, 116. + +Liquid medicinal soaps, 79. + +Liquid soaps, 94. + +Lyes, Spent, 37. + + +M + +Magnesia, Use in autoclave saponification, 120. + +Manganese sulfate, Use of as catalyzer in fermentative cleavage of fats, 122. + +Marine soaps, 39. + +Medicinal soaps, 76. + +Medicinal soaps, Less important, 78. + +Medicinal soaps, Therapeutic value of, 76. + +Melting point of fat or oil, Standard method, 193. + +Mercury soaps, 78. + +Metallic soaps, 1. + +Methyl orange, indicator, 136. + +Meyerheim, ref., 21. + +Mill soap, 32. + +Moisture in soap, Determination of, 138, 130. + +Moisture and volatile matter in fats and oils, Standard method for + detm. of, 170. + Note on method, 184-185. + +Mottle in soap, 81. + +Mug shaving soap, 90. + + +N + +Naphtha, Incorporation in soap, 49. + +Naphthenic acids, 24. + +Nigre, 36. + +Normal acids, Equivalent in alkalis, 136. + + +O + +Oils and fats, 1. + +Oils and fats, Chemical constants, 18. + +Oils and fats, Distinction, 1. + +Oils and fats, Preserving, 18. + +Oils and fat, Nature of used in soap manufacture, 2. + +Oils and fats, Rancidity of, 16. + +Oil hardening, 19. + +Oleic acid, 15, 19. + +Olein, 2, 19. + +Olive oil, 14. + +Olive oil foots, 14. + +Organoleptic methods, 127. + + +P + +Palmatin, 2. + +Palm kernel oil, 8. + +Palmitic acid, 2. + +Palm oil, 8. + +Palm oil, air bleaching, 12. + +Palm oil, Chrome bleaching of, 9. + +Palm oil soap, 66. + +Pearl ash, 29. + +Perfuming and coloring toilet soaps, 73. + +Peroxide soap, 78. + +Petroff reagent, 117. + +Pfeilring reagent, 117. + +Phenol, 77. + +Phenolphthalein, indicator, 38. + +Phenolphthalein, Using as indicator, 51. + +Phenols, Soaps containing, 77. + +Pinic acid, 22. + +Plodder, 33. + +Potash from wood ash, 27. + +Potassium carbonate, 29. + +Powders, Light, 60. + +Powders, Scouring, 61. + +Powders, Shaving, 90. + +Powders, Soap, 56. + +Precipitation test for treated spent lyes, 110. + +Prevention of rancidity, 18. + +Pumice or sand soaps, 93. + +Purple shade in soap, 75. + + +R + +Rancidity of oils and fats, 16. + +Rancidity, Prevention, 18. + +Recovery of glycerine from spent lye, 106. + +Red oil, 15. + +Red oil, Saponified, 15. + +Resin acids, Total fatty and, Determination of in soap, 144. + +Ribot, ref., 20. + +Rosin, 22. + +Rosin, Determination of in soap, 144. + +Rosin saponification, 23. + +Run and glued up soaps, 69. + +Run soaps, 39. + + +S + +Sal soda, 29. + +Salt, 30. + +Salting out, 30. + +Salt "pickle," 37. + +Sampling crude glycerine, 162. + +Sampling for standard method, 166. + Note on, 184. + +Sampling oils and fats, 128. + +Sampling soap, 137. + +Saponification by ferments, 121. + +Saponification, Acid, 120. + +Saponification, Aqueous, 121. + +Saponification, Autoclave, 118. + +Saponification, Carbonate, 45. + +Saponification defined, 2, 105. + +Saponification, Lime, 118. + +Saponification number, 181-182. + +Saponification, Rosin, 23. + +Saponification, Various methods, 105. + +Scouring and fulling soaps for wool, 98. + +Scouring powders, 61. + +Scouring soap, 61. + +Semi-boiled laundry soaps, 49. + +Semi-boiled process, 44. + +Shaving cream, 90. + +Shaving powder, 90. + +Shaving soaps, 87. + +Silica and silicates, Determination of in soap, 148. + +Silk dyeing, 102. + +Silk industry, Soaps used in, 101. + +Slabber, 32. + +Smith method for moisture in soap, 138. + +Soap analysis, 137. + +Soap, Automobile, 41. + +Soap, Carbolic, 71. + +Soap, Castile, 79. + +Soap, Chip, 54. + +Soap Chip, cold made, 55. + +Soap, Chip, unfilled, 56. + +Soap, Cold cream, 78. + +Soap, Coloring, 75. + +Soap containing phenols, 77. + +Soap, Curd, 71. + +Soap, Defined, 1. + +Soap, Determination insoluble matter, 143. + +Soap, Determining glycerine in, 149. + +Soap, Eschweger, 81. + +Soap, Floating, 62. + +Soap, Formaldehyde, 78. + +Soap for wool, Scouring and fulling, 98. + +Soap, Full boiled, 35. + +Soap, Iodine, 78. + +Soap kettle, 31. + +Soap, Laundry, 48. + +Soap, Liquid, 94. + +Soap lye crude glycerine, 113. + +Soap, Marine, 39. + +Soap, Medicinal, 76. + +Soap, Medicinal, less important, 78. + +Soap, Mercury, 78. + +Soap, Metallic, 1. + +Soap, Peroxide, 78. + +Soap powders, 56. + +Soap, Pumice or sand, 93. + +Soap, Rosin settled, 50. + +Soap, Run and glued up, 69. + +Soap, Scouring, 61. + +Soap, Semi-boiled laundry, 49. + +Soap, Shaving, 87. + +Soap, Sulphur, 77. + +Soap, Tannin, 78. + +Soap, Tar, 77. + +Soap, Test for color of, 133. + +Soap, Textile, 98. + +Soap, Toilet, 65. + +Soap, Toilet cheaper, 68. + +Soap, Toilet, cold made, 72. + +Soap, Toilet perfuming and coloring, 73. + +Soap, Transparent, 82. + +Soap, Transparent, cold made, 84. + +Soap used for cotton goods, 103. + +Soap used in the silk industry, 101. + +Soap, Witch hazel, 78. + +Soap, Wool thrower's, 100. + +Soap, Worsted finishing, 101. + +Soda ash, 28. + +Sodium carbonate, 28. + +Sodium perborate, Use of in soap powders, 57. + +Soft soaps, 40. + +Soluble mineral matter detm. of in fats and oils, 173. + Note on method, 187-188. + +Solvay process, 28. + +Soya bean oil, 14. + +Spent lye, Recovery of glycerine from, 106. + +Spent lyes, 37. + +Spent lyes, Treatment of for glycerine recovery, 107. + +Splitting fats with ferments, 121. + +Standard methods of analysis for fats and oils, 165-196. + +Starch and gelatine, Determination in soap, 143. + +Stearic acid, 15, 19. + +Stearin, 2, 19. + +Strengthening change, 36. + +Strengthening lyes, 38. + +Strunz crutcher, 63. + +Sugar in soap, Determination of, 150. + +Sugar, Use in transparent soap, 83. + +Sulfate of alumina, Use of in spent lyes, 108. + +Sulphonated oils, 104. + +Sulphur soaps, 77. + +Sweating of soap, 62. + +Sweet water, 119. + +Sylvic acid, 22. + + +T + +Talgol, 96. + +Tallow, 4. + +Tallow, Fullers' earth bleaching of, 4. + +Tallow, Improving color by extraction of free fatty acid, 6. + +Tannin soap, 78. + +Tar soap, 77. + +Test for color of soap, 133. + +Testing of alkalis used in soap making, 134. + +Textile soaps, 98. + +Titer, 130. + +Tank cars, Sampling, 166. + +Tierces, Sampling, 168. + +Titer, Standard method, 175. + +Titer, Note on, 189. + +Tung oil, Note one iodine, number of, 180. + +Toilet soap, 65. + +Toilet soaps, Cheaper, 68. + +Toilet soap, Use of hardened oils in, 96. + +Total alkali, Determination of in soap, 147. + +Total fatty and resin acids, Determination of in soap, 144. + +Train oils, 20. + +Transparent soap, 82. + +Transparent soap, Cold made, 84. + +Troweling soap, 52. + +Tsujimoto, ref., 20. + +Tubes for transparent soap, 85. + +Turkey red oil, 104. + +Twaddle scale, 25. + +Twitchell method for rosin, 145. + +Twitchell process, 113. + +Twitchell process, Advantages, 113. + + +U + +Unsaponifiable matter, Determination of in oils and fats, 132. + +Unsaponifiable matter, Determination of in soap, 148. + +Unsaponifiable matter, determination of by standard method, 176. + + +V + +Vacuum Oven, Standard, 176. + +Vegetable oils, 6. + + +W + +Water, 29. + +Water, Hard, 29. + +Witch hazel soap, 78. + +Wool thrower's soap, 100. + +Worsted finishing soaps, 101. + + +Z + +Zinc oxide, Use of in autoclave saponification, 120. + +Zinc oxide, Use of in soap, 33. + + + + +LITERATURE OF THE CHEMICAL INDUSTRIES + + +On our shelves is the most complete stock of technical, industrial, +engineering and scientific books in the United States. The technical +literature of every trade is well represented, as is also the literature +relating to the various sciences, both the books useful for reference as +well as those fitted for students' use as textbooks. + +A large number of these we publish and for an ever increasing number we +are the sole agents. + +ALL INQUIRIES MADE OF US ARE CHEERFULLY AND CAREFULLY ANSWERED AND +COMPLETE CATALOGS AS WELL AS SPECIAL LISTS SENT FREE ON REQUEST + +D. VAN NOSTRAND COMPANY + +_Publishers and Booksellers_ + +8 WARREN STREET NEW YORK + + +The Soap-Maker's Book Shelf + +A list of standard books relating to soapmaking and allied industries. + +Published and For Sale by + +D. VAN NOSTRAND COMPANY + +_Publishers and Booksellers_ + +8 WARREN STREET NEW YORK + + +~Askinson, George W.~ Perfumes and Cosmetics. Their preparation and +manufacture. Fourth Edition, translated from the German, and revised +with additions by W. L. Dudley. 32 illustrations. 6-1/4 × 9-1/2. Cloth. +354 pp. New York, 1915. ~$5.00~ + +~Chalmers, T. W.~ The Production and Treatment of Vegetable Oils. +Including chapters on the refining of oils, the hydrogenation of oils, +the generation of hydrogen, soap making, the recovery and refining of +glycerine, and the splitting of oils. 95 illustrations, 9 folding +plates. 8 × 11-1/2. Cloth. 163 pp. London, 1919. ~$7.50~ + +~Deite, C.~ Manual of Toilet Soap-Making. Comprising toilet soaps, +medicated soaps, and other specialties. Second Revised Edition. 85 +illustrations. 6-1/2 × 10. Cloth. 356 pp. London, 1920. ~$7.50~ + +~Ellis, Carleton G.~ The Hydrogenation of Oils, Catalyzers and Catalysis +and the Generation of Hydrogen and Oxygen. Second Edition, thoroughly +revised and enlarged. 240 illustrations. 6-1/4 × 9-1/2. Cloth. 767 pp. +N. Y., 1919. ~$7.50~ + +~Fischer, M. H.~ Soaps and Proteins, Their Colloid Chemistry in Theory and +Practice. With the collaboration of G. D. McLaughlin and M. O. Hooker. +114 illustrations. 6 × 9-1/4. Cloth. 281 pp. New York, 1921. ~$4.00~ + +~Holde, D.~ The Examination of Hydrocarbon Oils, and of the Saponifiable +Fats and Waxes. Translated from the Fourth German Edition by Edward +Mueller. 115 illustrations. 6-1/4 × 9-1/4. Cloth. 499 pp. N. Y., 1915. +~Net, $5.00~ + +~Hurst, G. H~. Soaps. A practical manual of the manufacture of domestic, +toilet and other soaps. Second Edition. 66 illustrations. 6 × 8-3/4. +Cloth. 385 pp. London, 1907. ~$6.00~ + +~Hurst, George H., and Simmons, W. H.~ Textile Soaps and Oils. A handbook +on the preparation, properties, and analysis of the soaps and oils and +in textile manufacturing, dyeing and printing. Third Edition, revised. +12 illustrations. 5-1/2 × 8-3/4. Cloth. 212 pp. London, 1921. ~$4.00~ + +~Koller, T. Cosmetics.~ A handbook of the manufacture, employment, and +testing of all cosmetic materials and cosmetic specialties, with +numerous recipes. Translated from the German. Third Edition. 5 × 7-1/2. +Cloth. 264 pp. London, 1920. ~$3.50~ + +~Koppe, S. W. Glycerine.~ Its introduction, Uses and Examination. For +chemists, perfumers, soapmakers, pharmacists, and explosives +technologists. 7 illustrations. 5-1/4 × 7-1/2. Cloth. 260 pp. New York, +1915. ~$3.50~ + +~Lamborn, L. L.~ Modern Soaps, Candles, and Glycerin. A practical manual +of modern methods of utilization of fats and oils in the manufacture of +soaps and candles, and the recovery of glycerin. 228 illustrations. +6-1/2 × 9-1/4. Cloth. 708 pp. N. Y., 1906. ~$10.00~ + +~Murray, B. L.~ Standards and Tests for Reagent Chemicals. 6 × 9. Cloth. +400 pp. New York, 1920. ~$3.00~ + +~Parry, Ernest J.~ The Chemistry of Essential Oils and Artificial +Perfumes. Vol. I, Monographs on Essential Oils. Fourth Edition, revised +and enlarged. 51 illustrations. 6-1/4 × 10. Cloth. 557 pp. London, 1921. +~$9.00~ + +Vol. II. Constituents of Essential Oils, Synthetic Perfumes and Isolated +Aromatics, and the Analysis of Essential Oils. Third Edition, revised +and enlarged. Illustrated. 351 pp. London, 1919. ~$7.00~ + +~Partington, J. R.~ The Alkali Industry. 63 illustrations. 5-1/2 × 8-1/2. +Cloth. 318 pp. London, 1918. ~$3.00~ + +~Rogers, Allen.~ Industrial Chemistry. A manual for the student and +manufacturer. Third Edition, thoroughly revised and enlarged. 377 +illustrations. 6-1/2 × 9-3/4. Flexible fabrikoid. 1255 pp. New York, +1920. ~$7.50~ + +~Scott, Wilfred W.~ (Editor). Standard Methods of Chemical Analysis. A +manual of analytical methods and general reference for the analytical +chemist and for the advanced student. Second Edition, revised, with +additional tables. 142 illustrations, 3 color plates. 7 × 9-1/4. Cloth. +900 pp. N. Y., 1917. ~$7.50~ + +~Simmons, W. H.~ Fats, Waxes and Essential Oils. ~In Press.~ + +~Simmons, William H.~ Soap. Its composition, manufacture and properties. +11 illustrations. 4-3/4 × 7-1/4. Cloth. 133 pp. London, 1916. ~$1.00~ + +~Simmons, W. H., and Appleton, H. A.~ The Handbook of Soap Manufacture. 27 +illustrations. 6 × 9. Cloth. 166 pp. London, 1908. ~$4.00~ + +~Van Nostrand's Chemical Annual.~ Edited by John C. Olsen. A handbook of +useful data for analytical manufacturing and investigating chemists and +chemical students. Fourth Issue, enlarged. 5 × 7-1/2. Flexible +fabrikoid. 785 pp. New York, 1918. ~$3.00~ + +~Watt, A.~ Art of Soapmaking. A practical handbook of the manufacture of +hard and soft soaps, toilet soaps, etc. Seventh Edition, revised and +enlarged. 43 illustrations. 5-1/4 × 7-1/2. Cloth. 323 pp. London, 1918. +~$4.00~ + +~Wright, C. R. A.~ Animal and Vegetable Fixed Oils, Fats, Butters, and +Waxes: Their Preparation and Properties, and the Manufacture Therefrom +of Candles, Soaps, and Other Products. Third Edition, revised and +greatly enlarged by C. Ainsworth Mitchell. 185 illustrations, 3 plates. +6 × 9. Cloth. 953 pp. London, 1921. ~$16.50~ + + + + + + +End of the Project Gutenberg EBook of Soap-Making Manual, by E. G. Thomssen + +*** END OF THIS PROJECT GUTENBERG EBOOK SOAP-MAKING MANUAL *** + +***** This file should be named 34114-8.txt or 34114-8.zip ***** +This and all associated files of various formats will be found in: + https://www.gutenberg.org/3/4/1/1/34114/ + +Produced by David Clarke, Josephine Paolucci and the Online +Distributed Proofreading Team at https://www.pgdp.net. 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