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FOR PUBLIC DOMAIN ETEXTS*Ver.04.29.93*END* + + + + + +Scanned by Charles Keller with OmniPage Professional OCR software + +TB is a triple bond. <.> is a dotted (coordinated) bond. +"Emphasis" _italics_ have a * mark. +[#] footnotes moved to EOParagraphs but NOT renumbered. +(They are numbered "a" or "b" when two pages of notes are together.) +Comments and guessed at characters in {braces} need stripped/fixed. +Greek letters are encoded in <gr > brackets, and the letters are +based on Adobe's Symbol font. + + + + + +ORGANIC SYNTHESES + +AN ANNUAL PUBLICATION OF SATISFACTORY METHODS FOR THE PREPARATION +OF ORGANIC CHEMICALS + +_EDITORIAL BOARD_ + +JAMES BRYANT CONANT, _Editor-in-Chief_ HANS THACHER CLARKE ROGER +ADAMS OLIVER KAMM + +_CONTRIBUTORS_ G. H. COLEMAN J, C. HESSLER E. P. KOHLER C. S. MARVEL +W. A. NOYES G. R. ROBERTSON E. B. VLIET F. C. WHITMORE + +VOL. II. + + + + +Caveat: Some numbers did not OCR correctly and may not have been +corrected during the proofing! Check the 1941 print edition +before trying these! + +INTRODUCTION TO THE SERIES + + +THE publication of this series of pamphlets has been undertaken +to make available in a permanent form complete detailed directions +for the preparation of various organic chemical reagents. +In announcing this purpose it may be well to mention at the outset +some of the difficulties in the way of the research chemist, which it +is hoped this series will be able to overcome. The cost of chemicals +is prohibitive to the majority of chemists; this was true before +the war when Kahlbaum's complete supply was available, and to-day +with our dependence on domestic stocks, this cost has increased. +The delay in obtaining chemicals, especially from abroad, +even if the expense need not be considered, is an important factor. +These difficulties have therefore thrown the research chemist on his +own resources. The preparation of materials for research, always time +consuming and annoying, is made increasingly so by the inexactness +of the published information which so often omits essential details. +Because of this, much needless experimentation is necessary +in order to obtain the results given in the published reports. +As the additional information thus acquired is seldom published, +duplication of such experiments occurs again and again,-- +a waste of time and material. It is hoped these difficulties +may be remedied by the publication of this series of pamphlets. +In other words, the authors hope to make this a clearing house +for the exchange of information as to methods of preparation of some +of the most needed organic chemical reagents. + +On account of the impossibility of obtaining the less common +organic chemicals in the United States during the past few years, +university laboratories have had no option but to prepare their +own supplies. At the University of Illinois, for instance, +a special study has been made of this field, and methods for +the production of various substances have been investigated. +As a result, reliable methods and directions have been developed +for producing the materials in one-half to five pound lots. +Such work as Illinois has done is now being given an even more extensive +scope at the Research Laboratory of the Eastman Kodak Company. It is +felt that the results from these various laboratories should be +available to all chemists and it is hoped that they eventually +will be completely incorporated in these pamphlets. + +The organic chemicals herein discussed have been quite +arbitrarily chosen, being those which have been needed in various +research laboratories in the last years and for which the directions +happen now to be ready for publication. The methods are in only +a few cases new ones; they are in general the most satisfactory +to be found in the literature. Only such details have been added +as will enable a man with a reasonable amount of experience +in organic chemistry to duplicate the results without difficulty. +To be absolutely sure that each set of directions can be repeated, +every experiment has been carried out in at least two laboratories. +Only after exact duplication of the results in both laboratories +are the directions considered ready for publication. +The names of the chemists who have studied the various experiments +are given so that further information concerning any obscure point +can be obtained if any question arises in using these directions. +And finally, in describing the experiments, special attention has +been given to the explanation of why it is necessary to follow +the directions carefully, and what will happen if these directions +are not followed. + +Although the main object in this series is to give the most convenient +laboratory methods for preparing various substances in one-half +to five pound lots, an attempt has also been made to have these +processes as far as possible adaptable to large scale development. +For example, extractions have been avoided wherever possible, +cheap solvents have been sub-stituted for expensive ones, +and mechanical agitation, a procedure extremely important in the +success of many commercial processes, has usually been specified. +The apparatus used is always carefully described and wherever necessary +an illustration is given. Accompanying each preparation there will +be found a bibliography containing references to all the methods +for the production of the substance described in the literature. +This is given in order to aid any future investigator who +may wish to study or improve the methods of preparation. +It is not claimed that the methods are, in every case, +completely perfect, but only that the yields are very satisfactory +and allow the production of the substances at a reasonable cost. +It is hoped therefore that the pamphlets will benefit not only +the scientific research man of the university, but also the +technical chemist who desires to develop the preparation of one +of these substances to a large scale process of manufacture. +The editors trust also that this work may be used to advantage +as a preparation manual in intermediate or advanced courses in +organic chemistry in university laboratories, and that it will aid +small colleges in the production of necessary reagents which they +are often financially unable to purchase. + +The pamphlets are to be edited by the following committee: +Roger Adams, University of Illinois, Urbana, Illinois; J. B. Conant, +Harvard University, Cambridge, Massachusetts; H. T. Clarke, Eastman +Kodak Company, Rochester, New York; Oliver Kamm, Parke, Davis Company, +Detroit, Michigan; each to act for one year as editor-in-chief +and the other three to assist him as associate editors. A new number +of the series will appear annually, and every five years the data will +be rearranged, revised, corrected, and then published in book form. +The number of preparations to be completed yearly is not fixed. +There will be, it is certain, about twenty; and it is hoped, +as the interest is stimulated in this work, that this number may +increase considerably. The editors especially desire to solicit +contributions from other chemists, not only in this country but abroad. +Whenever a compound is thoroughly and extensively studied in +connection with some research, it is hoped that complete directions +for its preparation will be assembled and sent to the editor. +He will then have them checked and published in a subsequent number. +Directions for the preparation of substances already on the market +are needed to make this work complete and will be gladly accepted. + +It will, of course, be recognized that an occasional mistake or omission +will inevitably be found in such a pamphlet as this which contains +so many references and formulae. The committee on publication will +therefore deem it a favor if they are notified when any such error +is discovered. It is hoped also that if any chemist knows a better +method for the preparation of any of the compounds considered, +or if anyone discovers any improvements in the methods, he will +furnish the authors with such information. Any points which may arise +in regard to the various preparations will be gladly discussed. +In conclusion, the editors are ready to do all they can to make this. +work successful, and welcome suggestions of any kind. +They feel that the success of the series will undoubtedly depend +upon the cooperation of others, and as its success promises to be +important to research chemists, the editors urge all interested +to assist. THE EDITORS + + + +TABLE OF CONTENTS + PAGE +I. BENZALACETOPHENONE...........................1 +II. BENZYL BENZOATE.............................5 +III. BENZYL CYANIDE.............................9 +IV. a, g-DICHLOROACETONE..............13 +V. _p_-DIMETHYLAMINOBENZALDEHYDE..................17 +VI. ETHYL OXALATE...............................23 +VII. ETHYL PHENYLACETATE........................27 +VIII. GLYCEROL a, g-DICHLOROHYDRIN....29 +IX. GLYCEROL a-MONOCHLORORYDRIN............33 +X. HYDRAZINE SULFATE............................37 +XI. MESITYLENE..................................41 +XII. METHYL RED.................................47 +XIII. _p_-NITROBENZOIC ACID.......................53 +XIV. _p_-NITROBENZYL CYAI~DE......................57 +XV. _p_-NITROPHENYLACETIC ACID....................59 +XVI. NITROSO-b-NAPHTHOL....................61 +XVII. PHENYLACETIC ACID.........................63 +XVIII. PHENYLACETYLENE..........................67 +XIX. PHENYLHYDRAZINE............................71 +XX. PHTHALIMIDE.................................75 +XXI. QUINOLINE..................................79 +XXII. QUINONE...................................85 +XXIII. SODIUM _p_-TOLUENESULFINATE................89 +XXIV. 1,3,5-TRINTROBENZENE......................93 +XXV. 2,4,6-TRINTROBENZOIC ACID..................95 + INDEX.....................................99 + + + +ORGANIC SYNTHESES + +I + +BENZALACETOPHENONE + +C6H5CHO + C6H5COCH3 + (NaOH)--> C6H5CH=CHCOC6H5 + H2O + +Prepared by E. P. KOHLER and E. M. CHADWELL. Checked by H. T. CLARKE +and R. P. LEAVITT. + +1. Procedure + +A SOLUTION of 218 g. of sodium hydroxide in 1960 g. +of water and 1000 g. of 95 per cent alcohol are introduced into +a 5500-cc. bottle which is loosely covered with a perforated disk +of cardboard, supplied with an effective stirrer, and supported +in a larger vessel so as to permit cooling with cracked ice. +Into the alkaline solution, 520 g. of pure acetophenone is poured, +the bottle is rapidly surrounded with cracked ice, and the stirrer started; +460 g. of benzaldehyde (U. S. P.) are then added at once. +The temperature of the mixture should not be below 15'0 and it +should not be allowed to rise above 30'0 during the reaction. +If it tends to do so, the stirring is not sufficiently vigorous. + +It is advantageous, though not essential, to inoculate the mixture +with a little powdered benzalacetophenone after stirring for half +an hour. After two to three hours, the mixture becomes so thick +that the stirring is no longer effective. The stirrer is then +removed and the mixture left to itself in an ice-box for about +ten hours. The mixture now is a thick paste composed of small +shot-like grains suspended in an almost colorless liquid. +It is cooled in a freezing mixture and then either centrifuged +or filtered on a large Buchner funnel, washed with water until +the washings are neutral to litmus, and finally washed with 200 cc. +of alcohol, which has previously been cooled to 0'0. After +thorough drying in the air, the crude product weighs about 880 g. +(yield 97 per cent of the theoretical amount) and melts at 50-54'0. +It is sufficiently pure for most purposes but tenaciously holds +traces of water. It is most readily purified by recrystallization +from four to four and a half times its weight of 95 per cent alcohol. +Eight hundred and eighty grams of crude product give 770 g. +(85 per cent of the theoretical amount) of light-yellow material +(m. p. 55-57'0) and 40-50 g. that require recrystallization. + +2. Notes + +The acetophenone should be as pure as possible (m. p. +20'0). Commercial acetophenone contains variable quantities of impurities +which reduce the yield. By distilling commercial acetophenone with +the help of a good still-head (preferably under diminished pressure) +and using only the fraction which boils at 201-202'0 (76-77'0/10 mm.) +greater quantities of benzalacetophenone can be obtained than by using +the entire sample. + +Commercial benzaldehyde can be used in place of the purer product, +but the amount used must be increased to make up for the impurities +which are present. + +If the temperature is too low, or the stirring too slow, the product +separates as an oil, which later solidifies in large lumps. + +If the temperature is allowed to rise above 30'0, secondary +reactions diminish both the yield and the purity of the product. +The most favorable temperature is 25'0. + +In recrystallizing benzalacetophenone, the alcohol should be saturated +at 50'0. If the solution is saturated above this temperature, +the benzalacetophenone tends to separate as an oil. The solution +should be allowed to cool gradually, and should finally be chilled +in a freezing mixture. 3. Other Methods of Preparation + +The methods for producing benzalacetophenone are: the action of acids +on a mixture of benzaldehyde and acetophenone or on a solution +of these substances in glacial acetic acid;[1] the condensation +of benzaldehyde and acetophenone with a 30 per cent solution of sodium +methylate at low temperatures;[2] the action of sodium hydroxide +on an alcoholic solution of benzaldehyde and acetophenone.[3] + +The methods based on the use of acids as condensing agents were +not considered, because Claisen, who devised them, abandoned them +after he found that alkaline condensing agents gave better results. +The preliminary experiments showed that condensation with sodium +methylate takes a long time and gives a product which it is difficult +to handle in large quantities. The method devised by Kostanecki +and Rossbach[3] has therefore been developed. + +[1] Ber. 14, 2463 (1881). + +[2] Ber. 20, 657 (1887). + +[3] Ber. 29, 1492 (1896). + + + +II + +BENZYL BENZOATE + +2 C6H5CHO + C6H5CH2ONa--> C6H5CO2CH2C6H5 + C6H5CH2ONa + +Prepared by O. KAMM and W. F. KAMM. Checked by ROGER ADAMS and +R. L. JENKINS. + +1. Procedure + +THREE grams of metallic sodium are dissolved by warming for half an hour +in 70 g. of pure benzyl alcohol (see notes), and after the mixture +has cooled to room temperature the solution is added gradually, +with thorough mixing, to 454 g. of c. p. benzaldehyde (which must +contain LESS than 1 per cent of benzoic acid). The reaction mixture has +a tendency to become warm, but the temperature should be kept slightly +below 50-60'0 by cooling, if necessary. A pasty gelatinous mass results. +After about half an hour the temperature of the mixture no longer rises; +it is then warmed on the water bath for about one or two hours, +with occasional shaking. + +The cooled reaction product is treated with 200 cc. +of water, the layer of oil separated, washed once with a second +portion of water, and subjected to distillation _in vacuo_. +The first fraction of the distillate contains benzyl alcohol together +with unchanged aldehyde, as well as a small quantity of water. +The temperature then rises rapidly to the boiling-point of +benzyl benzoate, when the receivers are changed. The product +boils at 184-185'0/15 mm., and analysis by saponification shows it +to consist of 99 per cent ester. A yield of 410-420 g. is obtained, +which corresponds to 90-93 per cent of the theoretical amount. +This benzyl benzoate supercools readily, but after solidifying +melts within one degree of the highest recorded value (19.4'0) and +therefore need not be refractionated, unless material of exceptional +grade is required. + +2. Notes + +In the presence of sodium benzylate two molecules of benzaldehyde +react with the alcoholate to form an addition product. +When the reaction mixture is overheated an important side reaction +may occur, as follows: + + / OCH2C6H5 + C6H5C -- OCH2C6H5 --> C6H5CO2Na + C6H5CH2OCH2C6H5 + \ ONa + +Dibenzyl ether no doubt forms the chief impurity in benzyl benzoate. +Since the boiling-point of the former lies near that of the ester, +it is not removed during the process of purification by distillation. + +The causes of variations in yield by the use of the older methods +can now be explained. When benzaldehyde is added TO THE ALCOHOLATE, +and especially when the latter is still warm, local overheating results; +in fact, the temperature may rise far above 100'0 with the result +that benzyl ether is formed. Simultaneously, the sodium benzylate +is converted into sodium benzoate, which is of no value for inducing +the desired reaction, and consequently very little benzyl benzoate +is obtained. The same side reactions explain the failure of this +experiment when the benzyl alcohol used in preparing the catalyst +(sodium benzylate) is contaminated with benzaldehyde. + +The benzyl alcohol used in this preparation must be free +from impurities, especially aldehyde. One cc. dissolved in 50 cc. +of water and treated with a freshly prepared clear solution of +phenylhydrazine acetate should give no appreciable precipitate. +If it is not pure, it must first be treated with alkali +as described below. + +The benzaldehyde should be titrated in order to determine its acidity. +If it is found to contain sufficient benzoic acid to react +with a considerable proportion of the sodium alcoholate, a poor +yield of ester will be obtained. Less than 1 per cent of benzoic +acid will not interfere seriously with the yields obtained, +but the presence of larger quantities of acid will be found to be +detrimental and must be removed by washing the benzaldehyde with +a sodium carbonate solution and redistilling with the precautions +necessary to prevent too free an access of air to the distillate. + +The order of mixing the reagents and the temperature of the ingredients +at the time of mixing are the most important factors in the experiment. +The temperature at which the reaction mixture is maintained +after mixing, provided that it is held below 100'0, is less important +from the standpoint of purity. + +The reaction mixture is not treated with acetic acid, as usually +recommended, for the reason that such a procedure yields a final +product contaminated with benzoic acid, unless an alkaline wash +is applied subsequently. + +The recovered benzyl alcohol can be used for the preparation +of a second lot of benzyl benzoate only after it has been boiled +with strong sodium hydroxide to remove all traces of benzaldehyde. + + +3. Other Methods of Preparation + +Benzyl benzoate has been identified in certain natural plant +products.[1] In the laboratory it has been prepared by the action of +(_a_) benzoyl chloride upon benzyl alcohol,[2] (_b_) benzyl chloride +upon sodium benzoate, and (_c_) alcoholates upon benzaldehyde.[3] +Recently, Gomberg and Buchler[4] have shown that reaction (_b_) may +be conducted even with aqueous solutions of sodium benzoate. + + +[1] Ann. 152, 131 (1869). + +[2] Gmelin's Handbuch der Organ. Chem. 3, 40. + +[3] Ber. 20, 649 (1887). Cf. also J. Chem. Soc. 75, 1155 (1899). + +[4] J. Am Chem. Soc. 42, 2059 (1920). + + +The Claisen method (_c_) furnishes the most convenient and practical +procedure for the preparation of this ester. The materials are cheap, +the experimental procedure simple, and the product obtained is free +from objectionable traces of benzyl chloride. Unfortunately the +method has been found to be extremely erratic in regard to yield +(10-95 per cent), as well as in regard to purity of the product +(87-97 per cent ester).[1] As a result of the present study,[2] +causes for variations are fully accounted for and the procedure +has been converted into a satisfactory method of preparation. + + +[1] C. A. 14, 3500 (1920). + +[2] J. Am. Pharm. Assoc. 11, 599 (1922). + + + +III + +BENZYL CYANIDE + +C6H5CH2Cl + NaCN--> C6H5CH2CN + NaCl + +Prepared by ROGER ADAMS and A. F. THAL Checked by O. KAMM and +A. O. MATTHEWS. + +1. Procedure + +IN a 5-l. round-bottom flask, fitted with a stopper holding +a reflux condenser and separatory funnel, are placed 500 g. +of powdered sodium cyanide (96-98 per cent pure) and 450 cc. +of water. The mixture is warmed on a water bath in order +to dissolve most of the sodium cyanide, and then 1 kg. +of benzyl chloride (b. p. 170-180'0) mixed with 1 kg. +of alcohol is run in through the separatory funnel in the course +of one-half to three-quarters of an hour. The mixture is then +heated with a reflux condenser on the steam bath for four hours, +cooled and filtered with suction to remove most of the sodium chloride. +It is well to wash the filtered salt with a small portion of +alcohol in order to remove any benzyl cyanide which may have been +mechanically held. The flask is now fitted with a condenser, +and as much alcohol as possible is distilled off on the steam bath. +The residual liquid is cooled, filtered if necessary, and the layer +of benzyl cyanide separated. This crude benzyl cyanide is now +placed in a Claisen distilling flask and distilled _in vacuo_, +the water and alcohol coming over first, and finally the cyanide. +It is advantageous to use a fractionating column or, better still, +a Claisen flask with a modified side-arm[1] (Vol. I, p. +40, Fig. 3) which gives the same effect as a fractionating column. +The material is collected from 135-140'0/38 mm. (115-120'0/10 mm.). +The yield is 740-830 g. (80-90 per cent of the theoretical amount). + +[1] J. Am. Chem. Soc. 39, 2718 (1917). 2. Notes + +The quality of the benzyl chloride markedly affects the yield +of pure benzyl cyanide. If a poor technical grade is used, +the yields will not be more than 60-75 per cent of the theoretical, +whereas consistent results of about 85 per cent or more were always +obtained when a product was used that boiled over 10'0. The technical +benzyl chloride at hand yielded on distillation about 8 per cent +of high-boiling material; a technical grade from another source was +of unusual purity and boiled over a 2'0 range for the most part. + +It is advisable to distil off the last portion of alcohol and water +_in vacuo_ and also to distil the benzyl cyanide _in vacuo_, +since under ordinary pressures a white solid invariably separates +during the distillation. + +One method of purifying the benzyl cyanide is to steam distil it +after the alcohol has been first distilled from the reaction mixture. +At ordinary pressures, this steam distillation is very slow and, +with an ordinary condenser, requires eighteen to twenty hours +in order to remove all of the volatile product from a run of 500 g. +of benzyl chloride. The distillate separates into two layers; the benzyl +cyanide layer is removed and distilled. The product obtained in this +way is very pure and contains no tarry material, and, after the excess +of benzyl chloride has been removed, boils practically constant. +This steam distillation is hardly advisable in the laboratory. + +The benzyl cyanide, prepared according to the procedure as outlined, +is collected over a 5'0 range. It varies in appearance +from a colorless to a straw-colored liquid and often develops +appreciable color upon standing. For a product of special purity, +it should be redistilled under diminished pressure and collected +over a 1-2'0 range. For most purposes, such as the preparation +of phenylacetic acid or ester, the fraction boiling 135-140'0/38 mm. +is perfectly satisfactory. 3. Other Methods of Preparation + +Benzyl cyanide occurs naturally in certain oils.[1] The only feasible +method of preparing it that has been described in the literature is +the one in which alcoholic potassium cyanide and benzyl chloride[2] +are employed. The cheaper sodium cyanide is just as satisfactory +as the potassium cyanide and therefore is the best material to use. +Gomberg has recently prepared benzyl cyanide from benzyl chloride +and an aqueous solution of sodium cyanide.[3] + + +[1] Ber. 7, 519, 1293 (1874); 32, 2337 (1899) + +[2] Ann. 96, 247 (1855); Ber. 3, 198 (1870); 14, 1645 +(1881); 19, 1950 (1886). + +[3] J. Am. Chem. Soc. 42, 2059 (1920). + + + +IV + +a, g-DICHLOROACETONE + +CH2ClCHOHCH2Cl + O(Na2Cr2O7 + H2SO4)--> CH2ClCOCH2Cl + H2O + +Prepared by J. B. CONANT and O. R. QUAYLE. Checked by A. W. DOX, L. YODER, +and O. KAMM. + +1. Procedure + +IN a 2-l. flask are placed 375 g. of commercial sodium dichromate, +225 cc. of water, and 300 g. of dichlorohydrin (b. p. +68-75'0/14 mm.). The flask is set in a water bath and equipped +with a thermometer and mechanical stirrer. The contents are +vigorously stirred, and 450 g. of sulfuric acid, diluted with 115 g. +of water, are introduced during the course of seven to eight hours. +It is convenient to add the acid at ten-minute intervals. +The temperature is kept between 20'0 and 25'0 during the entire reaction; +this is accomplished by adding a little ice to the water bath from +time to time. The stirring is continued for sixteen to seventeen +hours after all the acid has been added; as there is very little +heat evolved during this part of the reaction, the water bath may +be allowed to come to room temperature. + +Sufficient water is now added to the mixture to dissolve the pasty +chromium salts (300-800 cc.). The mass of crystals is then rapidly +filtered on a Buchner funnel and sucked as dry as possible. +The crystals are then transferred to a small laboratory centrifuge +and centrifuged for several minutes. The crystals are washed in +the centrifuge with about 15-25 cc. of ice water, then with 10-15 cc. +of cold petroleum ether, and finally centrifuged till as dry as possible. +The crude dichloroacetone is dried in a vacuum desiccator over +sulfuric acid overnight It weighs about 220 g. + +The crude product is best purified by distillation from +a 250-cc. distilling flask fitted with an air condenser. +A very small fraction (10-15 g.) of low-boiling material is obtained, +and the dichloroacetone (170-175'0) is then collected. It solidifies +in the receiver to a white crystalline mass which weighs 200-220 g. +(65-70 per cent of the theoretical amount). A few grams more may +be obtained by chilling the low-boiling fraction and filtering +off the water. + + +2. Notes + +Great caution should be exercised in working with dichloroacetone, +as it is extremely lachrymatory and blisters the skin. + +In transferring the crystals from the reaction flask to the Buchner +funnel it is necessary to use a certain amount of water to dissolve +the pasty chromium salts which are otherwise quite impossible +to filter. The amount necessary varies greatly in different runs, +according to the manner in which the chromium salts separate. +The amount of this water is kept low in order to dissolve +as little of the product as possible. Nevertheless, 10-15 g. +of dichloroacetone are thus dissolved; this material, together with +a little unchanged dichlorohydrin, may be recovered by a long +procedure involving extraction with ether and sodium bisulfite. +This is not profitable, however. + +It is not necessary to wash the crystals in the centrifuge until +they are white. A small amount of chromic salt will not interfere +with the subsequent purification. + +Commercial sodium dichromate is hygroscopic and contains varying +amounts of water. The 375 g. required in these directions are +equivalent to 319 g. of anhydrous material. + +The total time required for the oxidation is twenty-four hours. +It is convenient to start the reaction in the morning. +In this way the last part of the reaction, which requires +no attention, will be accomplished during the night. +The regulation of the temperature is necessary, as the reaction +proceeds very slowly below 20'0; on the other hand, the dichloroacetone +itself is oxidized at a somewhat higher temperature than 25'0. 3. +Other Methods of Preparation + +The preparation of dichloroacetone by the following methods +is described in the literature: the direct chlorination of +acetone;[1] the oxidation of dichlorohydrin;[2] the action of silver +chloride on diiodoacetone;[3] the action of dichloropropene +(CH2Cl-CCl=CH2) and hypochlorous acid;[4] the action of hydrochloric +acid on ethoxymonochloroacetoacetic ester;[5] and the hydrolytic +cleavage of dichloroacetoacetic ester.[6] + + +[1] Jahresb. 1859, 345; 1871, 531; J. prakt. Chem. (2)4, 52 +(1871); Ber. 7, 467 (1874); 8, 1330, 1438 (1875); 26, 598 +(1893); 42, 3233 (1909); Ann. 279, 315 (1894) + +[2] Ber. 6, 1210 (1873); 13, 1706 (1880); 42, 3233 (1909); Ann. +208, 355 (1881); 269, 46 (1892); Ann. chim. phys. (6) 9, 145 +(1886); Bull. soc. chim. (2) 36, 19 (1881). + +[3] Ann. 192, 93 (1878). + +[4] Compt. rend. 94, 1428 (1882). + +[5] Ann. 269, 18 (1892). + +[6] Ber. 43, 3533 (1910). + + + + +V + +_p_-DIMETHYLAMINOBENZALDEHYDE + +(CH3)2NC6H5 + HNO2--> (CH3)2NC6H4NO + H2O (CH3)2NC6H4NO + 2HCHO + + 2C6H5N(CH3)2 --> (CH3)2NC6H4N + = CHC6H4N(CH3)2 + 2H2) + (CH3)2NC6H4CHO +(CH3)2NC6H4N = CHC6H4N(CH3)2 + HCHO-->( CH3)2NC6H4N = CH2 + (CH3)2NC6H4CHO + +Prepared by ROGER ADAMS and G. H. COLEMAN. Checked by H. T. CLARKE +and W. W. HARTMAN. + +1. Procedure + +IN a 3-l. round-bottom flask fitted with a mechanical stirrer 150 g. +of technical dimethylaniline are dissolved in 750 cc. +of diluted hydrochloric acid (1 part concentrated acid to 1 +part water). This solution is now cooled to 0'0 and a solution +(previously cooled to 0'0) of 90 g. of technical sodium nitrite +in 150 cc. of water is added through a separatory funnel. +During the addition of the nitrite solution, mechanical stirring +should be employed and the flask cooled well with ice and salt. +The addition is made at such a rate (thirty to forty minutes +for the entire addition) that the temperature does not rise above +5'0. The precipitate of nitroso dimethylaniline hydrochloride +is filtered off with suction, then washed with about 300 cc. +of diluted hydrochloric acid (1:1). + +In a 2-l. beaker, 180 g. of technical dimethylaniline, 125 cc. +of formaldehyde (technical 40 per cent), and 300 cc. +of concentrated hydrochloric acid are mixed and heated for ten +minutes on a steam bath. The mixture is now placed in a hood +and the nitroso dimethylaniline added all at once, or as rapidly +as possible. The beaker is then covered with a watch glass. +A vigorous reaction soon occurs and is complete in about five minutes. +The resulting solution is transferred to a 5-l. flask and diluted +to 4 l.; stirring is started, and a 25 per cent solution of sodium +hydroxide is added until the red color disappears (about 650 cc. +are required). The yellow benzylidene compound separates, +is filtered with suction and washed with water. The moist precipitate +is transferred to a 4-l. glass jar, covered with 1000 cc. +of 50 per cent acetic acid and 250 cc. of formaldehyde, +and stirred until twenty minutes after the benzylidene compound has +gone into solution. While the mixture is being stirred vigorously +to prevent lumping of the precipitate, 400 cc. of water and 200 g. +of cracked ice are added during the course of five minutes. +The dimethylaminobenzaldehyde generally separates gradually +in fifteen to twenty minutes, but in some cases does not. +If the precipitate does not form, the solution is placed +in a refrigerator for a few hours or overnight. The mixture is +filtered with suction and washed at least ten times with 300 cc. +of water. The precipitate is sucked as dry as possible for fifteen +to thirty minutes. + +The slightly moist aldehyde is distilled under diminished +pressure from an oil bath, by means of a 1-l. Claisen flask. +A small amount of water comes over first, then the thermometer +rises rapidly to the boiling point of the aldehyde (180'0/22 mm.). +In changing receivers between the water fraction and the aldehyde, +care should be taken to keep the side-arm of the distilling +flask warm; otherwise, on starting the distillation again, +the aldehyde will solidify in the side-arm and cause trouble. +It is advisable not to collect the very last portion of the distillate +with the main portion, as the former is frequently quite red. +This is best added to crude material from another run. The main +distillate is dissolved in 100 cc. of alcohol in a 2-l. beaker, +then 1000 cc. of water are gradually added with vigorous mechanical +stirring to prevent lumping. The aldehyde separates, and is +filtered with suction. The product, when dry, weighs 125-130 g. +(56-59 per cent of the theoretical amount), and melts at 73'0. + +The aldehyde prepared in this way is in the form of small +granular crystals, which vary in different runs from a flesh color +to a lemon yellow. For practically all purposes, this slightly +colored product is entirely satisfactory and is essentially pure, +as can be judged by the melting point. For reagent purposes it +is desirable to remove the color completely, particularly since +the product obtained as just described has a tendency to take +on a reddish tinge on exposure to light. Further purification can +be accomplished by dissolving the aldehyde (it dissolves slowly) +in dilute hydrochloric acid (1 part of concentrated acid, sp. gr. +1.19, to 6 parts of water), 125 g. of aldehyde requiring 700 cc. +of the acid. The solution is placed in a jar and diluted with +half its volume of water, and dilute sodium hydroxide solution +(15-20 per cent) is added slowly with mechanical stirring. +At the beginning, the aldehyde comes down slightly colored. +After about 10 to 30 g. are precipitated, however, the product +appears white; this point can be readily seen. The first precipitate +is filtered off and added to the next run of crude material, +or fractionally precipitated again from hydrochloric acid. +The rest of the aldehyde is now precipitated by means of more sodium +hydroxide solution, and comes down almost white. At the very end of +the neutralization, particularly if the original product was quite yellow, +the last 4 to 5 g. of aldehyde should be precipitated separately, +as they are inclined to be slightly colored. If too much alkali is +added towards the end of the neutralization, a brown color appears, +but the addition of a little hydrochloric acid will destroy this color. +The main portion of the precipitate is filtered and dried; it weighs +95-100 g., m. p. 73'0. The succeeding runs yield 115-128 g. +of finished product, on account of the extra crude material obtained +from the distillation and reprecipitation of the previous run. 2. Notes + +The aldehyde that is obtained without reprecipitation +gradually takes on a pinkish tinge on exposure to light. +After the reprecipitation, however, this characteristic disappears. + +Thorough washing of the crude aldehyde is particularly desirable, +as it removes a reddish impurity which tends to distil over and +color the product lemon yellow or sometimes even brownish yellow. +When such a brownish product is obtained, it is quite necessary to make +a second precipitation, as well as to observe the directions mentioned +in the purification of the crude aldehyde, namely, to precipitate +the first few grams and the last few grams of the aldehyde separately. +The precaution of rejecting the first and last portions +of the precipitate is unnecessary in the reprecipitation. +In the reprecipitation of a deeply colored product, the portion +of aldehyde at the end may be even purplish in color and particular +care must be taken to keep this separate. + +Vigorous mechanical stirring must be employed during the precipitation +of the crude aldehyde, as otherwise large lumps are formed which +make washing difficult. + +A previous investigator has mentioned that the crude product must +be dried before distilling. This, however, is unnecessary. +If the aldehyde is dried before distilling, it is possible to use +a 500-cc. distilling flask instead of a 1-l one. + +In purifying the aldehyde by dissolving in acid and reprecipitating, +it is essential not to use stronger acid than that specified +(1:6), as stronger acid causes a deepening of the color of the solution. +If the concentrated acid, which is to be diluted and used in this +procedure, does not have a sp. gr. of 1.19, it will be necessary +to add the equivalent amount of weaker acid in order to dissolve +the _p_-dimethylaminobenzaldehyde. In purifying the aldehyde, +sodium carbonate may be used in place of sodium hydroxide +for precipitation, but it causes much foaming. + +When the apparatus for distilling, etc., is all set up, +a run such as described above requires about five to six hours +for completion. 3. Other Methods of Preparation + +_p_-Dimethylaminobenzaldehyde has been made by the condensation +of chloral with dimethylaniline, and subsequent hydrolysis;[1] +by the hydrolysis of tetramethyldiaminobenzhydrol with acetic +acid;[2] by the condensation of dimethylaniline, formaldehyde and +_m_-sulfo-_p_-tolyl hydroxylamine followed by hydrolysis;[3] by the +electrolytic reduction of a mixture of sodium nitrobenzene sulfonate, +dimethylaniline and formaldehyde, and subsequent hydrolysis;[4] +by the reduction of a mixture of dimethylaniline, formaldehyde and +sodium nitrobenzene sulfonate with iron and hydrochloric acid, +followed by hydrolysis;[5] by the condensation of alloxan with +dimethylaniline followed by hydrolysis;[6] by the condensation +of dimethylaniline, formaldehyde and sodium _p_-toluidine sulfonate +in the presence of hydrochloric acid and potassium dichromate +followed by hydrolysis.[7] The most satisfactory method, however, +is the condensation of dimethylaniline, formaldehyde and nitroso +dimethy]aniline, followed by hydrolysis,[8] a method which was first +described by E. Noelting and later perfected in detail by L. Baumann. + + +[1] Ber. 18, 1519 (1885); 19, 366 (1886); D. R. P. 61, 551; Frdl. +3, 109 (1892). + +[2] Ber. 27, 3317 (1894). + +[3] D. R. P. 103,578; Frdl. 5, 101 (1899). + +[4] D. R. P. 105,103; Frdl. 5, 107 (1899). + +[5] D. R. P. 105,105; Frdl. 5, 109 (1899). + +[6] D. R. P. 108,086; Frdl. 5, 117 (1899). + +[7] D. R. P. 118,567; Frdl. 6, 133 (1901). + +[8] Ber. 37, 858 (1904); J. Biol. Chem. 41, 146 (1920). + + + +VI + +ETHYL OXALATE + +(CO2H)2 + 2 C2H5OH--> (CO2C2H5)2 + 2H2O + +Prepared by H. T. CLARKE and ANNE W. DAVIS. Checked by ROGER ADAMS +and W. B. BURNETT. + +1. Procedure + + +IN a 5-l. flask are placed 1 kg. of crystallized (hydrated) oxalic +acid, 1.66 kg. of 95 per cent ethyl alcohol, and 1.33 kg. +of carbon tetrachloride. The flask is then fitted with a fractionating +column, I meter long, to which is attached a condenser and an automatic +separator so arranged that the lighter liquid flows off to a receiver +(Fig. 1). The heavier liquid flows through a tower of anhydrous +potassium carbonate, and then returns to the reaction flask. +The bottom of the tower is connected with a small separatory funnel +through which any potassium carbonate solution, which flows from +the solid in the tower, may be withdrawn from time to time. + +The mixture in the flask is slowly distilled. As soon as about 500 cc. +of the lighter liquid has collected, it is placed in a fractionating +apparatus and distilled, the material which boils up to 79'0 being +collected separately. This fraction, which consists principally +of alcohol, with a little carbon tetrachloride and moisture, is dried +with potassium carbonate and returned to the reaction mixture. +The higher fractions are redistilled. + +The above process is continued until the distillate no longer separates +into two phases (about twenty-seven hours). The liquid in the flask +is then distilled with the use of a column until the temperature +of the vapor reaches 85'0; the residue is then distilled under +reduced pressure, and the fraction which boils at 106-107/25 mm. +is collected. The yield is 920-960 g. of a colorless liquid +(80-84 per cent of the theoretical amount). + + +2. Notes + +Water, ethyl alcohol and carbon tetrachloride form a ternary +mixture boiling at about 61'0. This vapor mixture, on condensation, +separates into two phases; the heavier liquid consists of carbon +tetrachloride and alcohol with only small amounts of water; +the lighter liquid consists of approximately 65 per cent alcohol, +25 per cent water and 10 per cent carbon tetrachloride. +By taking advantage of this fact, it is possible to conduct +the esterification at a temperature so low that the ethyl hydrogen +oxalate first formed does not decompose into ethyl formate +and other products, as is the case when the customary methods +of esterification are employed. + +The reaction may be carried out somewhat more expeditiously +if the oxalic acid be dehydrated independently before it is mixed +with the alcohol; indeed, it is also possible to remove the bulk +of the water from the alcohol itself by a similar method, before mixing +it with the oxalic acid. However, since water is formed during +the esterification, little is gained by this procedure. + +It is not absolutely necessary to remove the last traces of water from +the alcohol-carbon tetrachloride layer by means of potassium carbonate +before returning it to the reaction mixture; this process is, however, +so simple and requires so little attention that there is no doubt +that it is of material aid in cutting down the time of operation. +The advantages of using crystallized oxalic acid and commercial 95 +per cent alcohol, instead of the anhydrous reagents, are obvious. +When technical oxalic acid is used, the yields are usually smaller +by 5 to 10 per cent. + +The apparatus shown in Fig. 1 may be somewhat more simply constructed +by using rubber connections in several places, thus eliminating a certain +amount of glass blowing, and making a more flexible piece of apparatus. +The side-arm of the separator may be made with two rubber connections,-- +one above and one below the tube leading to the potassium carbonate tube. +The long return tube to the flask may be constructed with a rubber +joint very near the carbonate tube and one near the flask. + + +3. Other Methods of Preparation + +Ethyl oxalate has been prepared in poor yields by the following methods: +by distilling a mixture of anhydrous oxalic acid and absolute +alcohol;[1] by heating a mixture of anhydrous oxalic acid and 97 per +cent alcohol under a reflux condenser and fractionating the resulting +mixture;[2] by distilling a mixture of anhydrous oxalic acid +and absolute alcohol, the vapor of absolute alcohol being passed +simultaneously into the mixture;[3] by allowing a saturated solution +of oxalic acid in alcohol to stand for a long time at 40-50'0.[4] + +A good yield has been obtained by Anschutz[5] by a method involving +saturation of a mixture of crystallized oxalic acid and alcohol +with hydrogen chloride, removal of the alcohol and water by +distillation under reduced pressure, and repetition of the treatment +with the alcohol and hydrogen chloride, the process being carried +out several times. + + +[1] Jahresb. 1861, 598. + +[2] J prakt. Chem. (2), 34, 500 (1886). + +[3] Monatsh. 17, 614 (1896). + +[4] Ann. 65, 350 (1848). + +[5] Ber. 16, 2414 (1883), + + + +VII + +ETHYL PHENYLACETATE + +C6H5CH2CN + C2H5OH + H2SO4 + H2O--> C6H5CH2CO2C2H5 + NH4HSO4 + +Prepared by ROGER ADAMS and A. F. THAL. Checked by OLIVER KAMM. + +1. Procedure + +IN a 3-l. round-bottom flask, fitted with an efficient +reflux condenser, are mixed 750 g. of 95 per cent alcohol, 750 g. +of concentrated sulfuric acid and 450 g. of benzyl cyanide. +The mixture, which soon separates into two layers, is heated +to boiling over a low flame, for six to seven hours, cooled and +poured into 2 l. of water, and the upper layer is separated. +This is washed with a little 10 per cent sodium carbonate solution +to remove small amounts of phenylacetic acid which may have been formed, +and then distilled _in vacuo_. A small amount of water goes +over first and then a pure product boiling 132-138'0/32 mm. +(120-125'0/17-18 mm.). The yield varies in general between 525 and 550 g. +(83-87 per cent of the theoretical amount). + + +2. Notes + +The benzyl cyanide can be most conveniently prepared according +to the directions in preparation III (p. 9); the product which boils +over a 5'0 range should be used. + +In washing the layer of ethyl phenylacetate with sodium carbonate it +is sometimes advisable to add a certain amount of sodium chloride +so that the ester will separate more readily. + +The product obtained is water-clear and practically colorless. +Although the product is collected over a 5'0 range, most of +the liquid is found to boil over a 1'0 range, if distilled +slowly without superheating. + +The boiling point of ethyl phenylacetate is near that of benzyl cyanide. +However, a Kjeldahl analysis of the product shows that only a trace +of nitrogen compounds is present. + + +3. Other Methods of Preparation + +Ethyl phenylacetate may be prepared by the treatment of benzyl +cyanide with alcohol and hydrochloric acid gas.[1] It is much more +convenient in the laboratory, however, to use sulfuric acid in place +of hydrochloric acid; in fact, the yields obtained are better +than those recorded in the literature. This ester may also be +made by the esterification of phenylacetic acid with hydrochloric +acid and alcohol;[2] or with alcohol and sulfuric acid;[3] +the following less important methods of preparation may be mentioned; +the action of benzyl magnesium chloride upon ethyl chlorocarbonate,[4] +and the action of copper on a mixture of bromobenzene and ethyl +chloroacetate at 180'0.[5] + + +[1] Ber. 20, 592 (1887); Ann. 296, 361 (1897) + +[2] Ber. 2, 208 (1869). + +[3] Ann. 296, 2, footnote (1897); Compt. rend. 152, 1855 (1911). + +[4] Ber. 36, 3088 (1903). + +[5] Ber. 2, 738 (1869). + + + +VIII + +GLYCEROL a, g-DICHLOROHYDRIN + +C3H5(OH)3 + 2HCl--> CH2ClCHOHCH2Cl + 2H2O + +Prepared by J. B. CONANT and O. R. QUAYLE. Checked by O. KAMM +and A. O. MATTHEWS. + + +1. Procedure + +ONE kilo of 90 per cent glycerol (sp. gr. 1.243) and 20 g. +of acetic acid are placed in a weighed 2-l. flask which is immersed +in an oil bath heated to 100-110'0. The flask is fitted with a +two-hole stopper, which carries a long tube reaching to the bottom +of the flask and a short exit tube. The former is connected +to a hydrogen chloride generator, the latter to a catch-bottle +and some system for absorbing any excess of hydrogen chloride. +A stream of dry hydrogen chloride is passed into the mixture. +The absorption of gas is very rapid at the start, but gradually +falls off towards the end of the reaction; the stream of hydrogen +chloride should be regulated accordingly. The flask is removed +from time to time and weighed; when the absorption of gas +practically ceases, the increase in weight will be about 875 g. +(25 per cent more than the theoretical amount). + +The product is now cooled, placed in a 4-l. beaker, and treated +with solid sodium carbonate until just alkaline to litmus. +Water is added from time to time, to facilitate the reaction +with the sodium carbonate and to prevent the separation of salt; +about 500 cc. are required. The mixture is transferred +to a separatory funnel and the aqueous layer separated. +The crude dichlorohydrin, which weighs 1250 g., is distilled in vacuo. +The first fraction boiling below 68'0/14 mm. weighs 225 g., and consists +of water and some dichlorohydrin; the dichlorohydrin is collected +between 68-75'0/14 mm., and weighs about 775 g. The water is separated +from the first fraction, which is then redistilled and yields 100 g. +of dichlorohydrin. A still further amount of material (40-45 g.) +may be obtained by extracting with benzene, the aqueous layer obtained +in the neutralization process. This is, however, hardly profitable. +The neutralization and distillation will require about four hours. + +The 875 g. of dichlorohydrin thus obtained boils over a +7'0 range; this is 70 per cent of the theoretical amount. +Redistillation yields 700-720 g. boiling 70-73'0/14 mm. +(57 per cent of the theoretical amount). + + +2. Notes + +The most convenient hydrogen chloride generator is that described +by Sweeney.[1] Concentrated hydrochloric acid is introduced +into concentrated sulfuric acid, by means of a dropping funnel +and a _capillary tube leading to the bottom of the sulfuric +acid container_. It is convenient to use a 3-l. bottle for this +container and a 1-l. funnel to contain the hydrochloric acid. +The gas is dried by passing through a wash-bottle containing +concentrated sulfuric acid. An empty catch-flask should be +connected between the generator and the absorption flask in case +any glycerol tends to suck back at the start of the reaction. +About 6 kg. of concentrated hydrochloric acid and 10 kg. +of concentrated sulfuric acid are required in one run. +The generating flask will have to be recharged every six hours; +it should be half filled with sulfuric acid. Aside from this, +the apparatus needs no attention. The oil bath can be conveniently +heated on an electric hot plate. + +The dichlorohydrin boiling over a 7'0 range is sufficiently pure for +most purposes. It contains very little, if any, isomeric dichlorohydrin, +since on oxidation it gives dichloroacetone in good yields. + + +3. Other Methods of Preparation + +The following methods of preparing dichlorohydrin are described +in the literature: the action of gaseous hydrogen chloride on +glycerol;[1b] the action of gaseous hydrogen chloride on glycerol +mixed with an equal volume of acetic acid;[2] the action of hydrogen +chloride gas on glycerol containing 1-2 per cent of some organic acid, +as acetic, as a catalyst;[3] the action of aqueous solution of +hydrochloric acid on glycerol containing acetic acid as a catalyst;[4] +the action of sulfur monochloride on glycerol.[5] + +The previous work, described in the literature, indicated that the best +yields were obtained by the treatment of glycerol containing 1-2 per +cent of acetic acid as a catalyst by gaseous hydrogen chloride. +Therefore this method was employed. + + +[1a] J. Am. Chem. Soc. 39, 2187 (1917) + +[1b] Ann. 88, 311 (1853); Ann. chim. phys. (3) 41, 297 (1854); +(6), 22, 437 (1891); Bull. soc. chim. (2), 48, 237 +(1887); Z. physik. Chem. 92, 717 (1918); 93, 59 (1919); 94, 691 +(1920); D. R P. 263,106; 272,337; Frdl. 11, 33 (1912). + +[2] Ann. Spl. 1, 2I8 (1861); Ann. chim. phys. (3) 60, 18 (1860). + +[3] D. R. P. 197,308; Frdl. 9, 33 (1908). + +[4] D. R. P. 197,309; Frdl. 9, 33 (1903). + +[5] Ann. 122, 73 (1862); 168, 43 (1873); Ber. 5, 354 +(1872); Ann. chim. phys. (6) 22, 437 (1891). + + + +IX + +GLYCEROL a-MONOCHLOROHYDRIN + +C3H5(OH)3 + HCl--> CH2ClCHOHCH2OH + H2O + +Prepared by J. B. CONANT and O. R. QUAYLE. Checked by O. KAMM +and A. O. MATTHEWS. + + +1. Procedure + +FIVE HUNDRED grams of glycerol (90 per cent) and 10 g. +of glacial acetic acid are mixed in a weighed 1-l. flask, +which is placed in an oil bath heated to 105-110'0. A rapid +stream of dry hydrogen chloride is introduced into the mixture. +The flask is removed from the bath from time to time and reweighed. +At the end of about four hours the flask will have gained 190 g. +in weight. The reaction is then complete. + +The product is distilled under diminished pressure. +Below 114'0/14 mm., 220-250 g. distil; this portion is mostly water. +The monochlorohydrin is collected between 114-120'0/14 mm.; +it weighs 360 g., which is 66 per cent of the theoretical amount. +About 20 g. more may be obtained by neutralizing the first fraction +and separating the aqueous layer. + + +2. Notes + +The same apparatus is employed as in the preparation of dichlorohydrin +(preparation VIII, p. 29). + +The portion boiling 120-130'0/14 mm. only amounts to 15-30 +g., showing that very little of the b-compound is formed. +This is further shown by the fact that the dichlorohydrin formed +by continued action of hydrogen chloride under the same conditions +contains very little, if any, a, b dichloride. + +Two kilograms of concentrated sulfuric acid and 750 g. +of concentrated hydrochloric acid are sufficient to produce +the necessary amount of hydrogen chloride. + +A light straw-colored final product is obtained in some cases. + +An alternative procedure which is slower and gives slightly +lower yields, but does not require a hydrogen chloride generator, +is as follows: + +Three hundred grams of glycerol, 600 cc. of hydrochloric acid +(sp. gr. 1.19) and 15 g. of glacial acetic acid are heated +under a reflux condenser for ten hours, in a 2-l. flask. +The boiling should be very gentle in the early stage of +the reaction, as considerable hydrochloric acid vapor is evolved. +As the reaction progresses, and the evolution of acid vapors diminishes, +the mixture is more strongly heated. + +The reaction products are distilled under ordinary pressure until +the temperature of the liquid has reached 140'0 (thermometer bulb +immersed in the liquid). The residual products are distilled +under diminished pressure, and the following fractions obtained. +(1) Up to 115'0/11 mm.; (2) 115-117'0/ 11 mm.; (3) 117-170'0/11 mm. +(1) is mostly aqueous hydrochloric acid; (2) is the monochlorohydrin; +and (3) is glycerol. The second portion is redistilled and the portion +boiling at 115-118'0/11 mm. or 133-136'0/20 mm. is collected. +The yield is 190-205 g., 53-57 per cent of the theoretical amount. + + +3. Other Methods of Preparation + +The following methods of preparing monochlorohydrin are described +in the literature: action on glycerol of gaseous hydrogen +chloride;[1] action of gaseous hydrogen chloride on glycerol +mixed with an equal volume of acetic acid;[2] action of aqueous +hydrochloric acid on glycerol[3] alone or with an organic acid +(1-2 per cent), such as acetic, as a catalyst;[4] gaseous hydrogen +chloride with an organic acid, as acetic, as a catalyst;[1b] gaseous +hydrogen chloride with the ester of an organic or inorganic acid +as a catalyst;[2b] the action of sulfur monochloride on glycerol.[3b] + +[1] Ann. 88, 311 (1853); Ann. chim. phys. (3) 41, 297 +(1834); V. R. P. 254,709; 269,657; Frdl. 11, 31 (1912). + +[2] Ann. chim. phys. (3) 60, 18 (1860). + +[3] D. R. P. 180,668; Frdl. 8, 27 (1907); J. Am. Chem. Soc. 42, 2096 +(1920). + +[4] D. R. P. 197,309; Frdl. 9, 34 (1908). + +[1b] D. R. P. 197,308; Frdl. 9, 33 (1908). + +[2b] D. R. P. Anm. 23,510; 16,579; Frdl. 9, 36 (1908). + +[3b] D. R. P. 201,230; Frdl. 9, 35 (1908). + + + +X + +HYDRAZINE SULFATE + +2 NH3 + NaOCl--> NH2NH2 + H2O + NaCl + +Prepared by ROGER ADAMS and B. K. BROWN. Checked by J. B. CONANT +and W. L. HANAWAY. + +1. Procedure + +A NORMAL solution of sodium hypochlorite is prepared as follows: +in a 5-l. round-bottom flask are placed 1800 g. of sodium +hydroxide solution (300 g. of sodium hydroxide to 1500 g. +of water) and 1500 g. of ice. Chlorine gas is then passed into +the solution until it has gained in weight approximately 213 g. +During this addition, the solution must be kept thoroughly +cooled with ice, in order that chlorates will not be formed. +After all the chlorine has been passed in, it is necessary to be +certain that the mixture is slightly alkaline, since any excess +of free chlorine in the solution prevents the formation of hydrazine. + +In a 14-inch evaporating dish are placed 1500 cc. +of c. p. ammonia water (sp. gr. 0.90), 900 cc. of distilled water, +375 cc. of 10 per cent gelatine solution, and 1200 cc. +of the normal sodium hypochlorite solution prepared as above. +This mixture is heated as rapidly as possible and boiled down +until one-third of the original volume is left. This solution +is then cooled thoroughly with ice and filtered with suction, +first through two layers of toweling and then through one +thickness of ordinary filter paper over cloth, in order to remove +finely divided solid impurities. The solution is then placed +in a precipitating jar, and cooled down thoroughly (0'0) with ice +and salt; 10 cc. of concentrated sulfuric acid for each 100 cc. +of solution are gradually added with constant stirring. +A precipitate of hydrazine sulfate (NH2NH2<.>H2SO4) forms. +The mixture is allowed to stand in the cold for a few hours in order +to complete the precipitation, and is then filtered by suction in the +usual way and washed with cold alcohol. The yield varies from 53 g. +to 58 g. per 1500 cc. of ammonia water (34-37 per cent of the +theoretical amount). The product is perfectly white and crystalline, +and satisfactory for almost any purpose. If an absolutely pure +product is desired, it must be recrystallized from water. +For every 21 g. of crude product, 100 g. of boiling water are used. +If the crude hydrazine is brown, it is advisable to use a little +bone-black. After the mixture has been filtered and cooled to 0'0, 19 g. +of pure white crystals are obtained. + + +2. Notes + +In the preparation of the sodium hypochlorite solution it is quite +necessary that the mixture be kept cold and be alkaline to red +litmus paper at the end of the reaction, if good yields of hydrazine +are to be obtained. + +Since iron is an anti-catalyzer, it is necesssary{sic} to use +distilled water throughout the process. + +As a viscolizer, a substance such as starch, glycerol, glue or +gelatine may be used; the last, however, gives by far the +most satisfactory results. + +In order to obtain a pure white hydrazine sulfate as the +first precipitate, it is necessary to cool the hydrazine solution +thoroughly and filter it twice before the sulfuric acid is added. +Moreover, the sulfuric acid must be added slowly and with stirring. +If these conditions are not followed, material containing +brown particles results. + +The mother liquor obtained from the crystallized hydrazine +sulfate contains a small amount of hydrazine. If 200 g. +of copper sulfate are dissolved in water and added to 10 l. +of the filtrates from the above processes, a light-blue crystalline +precipitate of the double salt of copper sulfate and hydrazine +sulfate will be formed after ten hours. This salt, when suspended +in ten times its weight of distilled water and treated with hydrogen +sulfide, decomposes into copper sulfide and hydrazine sulfate. +After the copper salt has been filtered off, the solution +is concentrated until the hydrazine sulfate crystallizes. +The yield of product is small, so that it is hardly advisable +to undertake this recovery in the laboratory. + +It is possible for one man, simultaneously evaporating six dishes +of the hydrazine mixture, to turn out from 20 to 25 runs in nine hours. +The time for the evaporation of a solution, such as is mentioned +in the experimental part, with a four-flame Bunsen burner, is two to +three hours; if the evaporation is carried out more slowly than this, +the yield of product is distinctly diminished. + + +3. Other Methods of Preparation + +Hydrazine salts have been prepared by the action of hypochlorites on +ammonia[1] or urea;[2] by the hydrolysis of salts of sulfohydrazimethylene +disulfonic acid;[3] by the hydrolysis of triazoacetic acid;[4] by the +reduction of diazoacetic ester;[5] by the reduction of nitroguanidine +followed by hydrolysis;[6] by the reduction of the nitroso derivatives +of hexamethylene tetramine;[7] by the reduction of nitrates or nitrites +with zinc in neutral solution;[8] by the action of sodium bisulfite +on hyponitrous acid followed by reduction;[1b] by the reduction +of K2SO3N2O2;[2b] by the action of ammonia on dichlorourea;[3b] +by the reduction of nitrosoparaldimin;[4b] by the action of copper +sulfate on ammonia at high temperatures;[5b] by the reduction of +methylene diisonitrosoamine;[6b] by the hydrolysis of the addition +product of diazoacetic ester and fumaric or cinnamic esters.[7b] + + +[1] D. R. P. 192,783; Chem. Zentr. 1908 (I), 427; Chem. Ztg. 31, 926 +(1907); D. R. P. 198,307; Chem. Zentr. 1908 (I), 1957; Eng. Pat. +22,957; C. A. 2, 1999 (1908); U. S. Pat. 910,858; C. A. 3, 1065 +(1909); French Pat. 382,357; C. A. 3, 2358 (1909); Ber. +40, 4588 (1907); Laboratory Manual of Inorganic Preparations, +by A. B. Lamb, Harvard University, Cambridge, Mass. + +[2] J. Russ. Phys. Chem. Soc. 37, 1 (1905); Chem. Zentr. 1905 +(I) 1227; D. R. P. 164,755; Frdl. 8, 53 (1905); French Pat. 329,430; +J. Soc. Chem. Ind. 22, 1063 (1903); Chem. Zentr. 1905 (I) 1227. + +[3] D. R. P. 79,885; Frdl. 4, 26 (1895); Ber. 28, 2381 (1895). + +[4] Ber. 20, 1632 (1887); Chem. News 55, 288 (1887); D. R. P. 47,600; +Frdl. 2, 554 (1889); J. prakt. Chem. (2) 39, 27 (1889). + +[5] Ber. 27, 775 (1894); 28, 1848 (1895); D. R. P. 58,751; Frdl. 3, 16 +(1891); D. R. P. 87,131; Frdl. 4, 28 (1896). + +[6] Ann. 270, 31 (1892); D. R. P. 59,241; Frdl. 3, 16 +(1891); Eng. Pat. 6,786; J. Soc. Chem. Ind. 11, 370 (1892). + +[7] D. R. P. 80,466; Frdl. 4, 27 (1895); Ann. 288, 232 (1895). + +[8] Eng. Pat. 11, 216; J. Soc. Chem. Ind. 14, 595 (1895). [1b] Ber. +33, 2115 (1900); Ann. 288, 301 (1895). + +[2b] Ber. 27, 3498 (1894). + +[3b] J. Chem. Soc. 95, 235 (1909); Chem. News 98, 166 (1908). + +[4b] Ber. 23, 752 (1890). + +[5b] Chem. News 66, 223 (1892). + +[6b] Ber. 27, 3292 (1894); + +[7b] Ber. 21, 2637 (1888). + + + +XI + +MESITYLENE + +3 CH3COCH3 + (H2SO4)--> C6H3(CH3)3 +3H2O + +Prepared by ROGER ADAMS and R. W. HUFFERD. Checked by H. T. CLARKE +and W. W. HARTMAN. + +1. Procedure + +IN a 12-l. round-bottom flask, arranged so that the contents +can be mechanically stirred, are placed 4600 g. (5750 cc.) +of technical acetone. The flask is then well cooled with an +ice-and-salt mixture, until the temperature of the acetone +is between 0'0 and 5'0. Stirring is started, and 4160 cc. +of commercial concentrated sulfuric acid is run in at such a rate +that the temperature of the mixture never rises above about 10'0. +This addition is accomplished in about five to ten hours. +The stirring is continued for three to four hours longer, +while the flask still remains immersed in the original +freezing mixture to which no further amount of ice is added. +The mixture is then allowed to stand at room temperature for eighteen +to twenty-four hours. + +A 5-l. round-bottom flask is fitted with a rubber stopper or a cork +stopper coated with pitch, carrying two glass tubes, one of which +(for the entrance of steam) reaches to the bottom of the flask, +while the other extends into the open end of a condenser set for +downward distillation. The stopper should be wired into the flask. +The glass delivery tube into the condenser should not be less than a +12-mm. bore, and the condenser should consist of two 120-cm. water-cooled +condensers attached end to end. To the end of the condensing system, +an adapter is attached, the small end of which is at least 8 mm. +in bore and is fitted tightly into a stopper in a 2-l. suction flask. +To the side-arm of the suction flask is attached a tube leading to an +exhaust fan, in order to carry away the gases which are evolved during +the subsequent distillation. In the 5-l. flask are placed about 2 l. +of the sulfuric acid-acetone reaction mixture, and the flask +is then heated with a free flame and shaken occasionally. +A reaction starts at the end of about fifteen or twenty minutes, +as shown by the evolution of gas (chiefly sulfur dioxide), and is +allowed to run for about three minutes. At the end of this time, +a current of steam is passed in and continued for about three minutes. +During this period a large proportion of the mesitylene distils +and should be kept separate from the subsequent distillate. +The steam distillation is continued at such a rate that about 800 cc. +distils in twenty-five to thirty minutes and is collected as a +second distillate. At the end of this time, the distillation +is stopped, the water poured off from the distilling flask +and the tarry material emptied out while hot into waste jars. +The total amount of original reaction mixture requires +five distillations similar to the one just described. +The first distillates from each of the five distillations are mixed, +and the layer of mesitylene is separated from the water. +This is shaken with sodium hydroxide solution until no more odor of sulfur +dioxide is noticeable, then washed twice with water and distilled. +The first portion of the distillate consists of a small amount of water +and mesitylene and is added to the combined second distillates. +The fraction which distils up to 210'0 is saved. The second distillates +are combined, washed in the same way as the first and then distilled; +the fraction which distils up to 210'0 is combined with the corresponding +fraction from the first distillates. + +These combined fractions (which boil up to 210'0) and 15 g. +of sodium are placed in a 2-l. distilling flask, the side-arm of +which is closed with a rubber tube and pinchcock and which is fitted +with a reflux condenser. The mixture is heated just below the boiling +point for about three hours, during which time the impurities are +attacked by the molten sodium, and a gelatinous, reddish mass forms. +The reflux condenser is now removed and one set for downward +distillation is attached to the side-arm. The mixture is distilled +and about two-thirds of the liquid removed in this way. +The residue is cooled, the liquid poured off from solid material +and distilled up to 210'0. + +The distillates from the sodium treatment are now fractionated with +a good column (at least 30 cm. long), and the portion which boils +at 163-167'0 is collected. The yield of this fraction varies in +different runs from 430 to 470 g. (13-15 per cent of the theoretical +amount), but very often will be as high as 500 g., and has reached, +in certain experiments, 600 g. + +An alternative method for the purification of the crude material +has been employed by Clarke and Hartman, and yields a slightly +higher-grade product than the sodium method. It is as follows: + +The combined distillates are treated with an equal volume of concentrated +sulfuric acid and the solution warmed on a water bath for an hour, +under a reflux condenser, with occasional shaking or, better, with +mechanical stirring. Upon cooling, mesitylene sulfonic acid crystallizes +and the unsulfonated material remains as an oil on the surface. +The mixture is filtered through flannel or a "filtrose" plate, +and the crystals are washed with 60-70 per cent sulfuric acid. +The oily layer is again warmed with sulfuric acid, as before. +The acid and oily filtrates from the two sulfuric acid treatments are steam +distilled, and the distillate combined with the next batch of material. +The crystals are mixed with 2 l. of 15 per cent hydrochloric +acid and heated under a reflux condenser for two to three hours. +The reaction mixture is now steam distilled, the mesitylene separated, +dried over calcium chloride and fractionated; the portion which boils +at 163-167'0 is collected. + +2. Notes + +The cooling of the reaction flask must be very efficient, a 10-15 cm. +blanket of a thorough mixture of ice and salt being used. +If this precaution is not employed, the time for the addition +of the sulfuric acid is greatly increased, provided the temperature +of the reaction mixture is still kept within the limits mentioned. + +If a cork is used for the steam distillation of the reaction mixture +of acetone and sulfuric acid, it should be coated well with pitch and wired +into the flask. This is necessary because the vapors of the reaction +mixture attack an ordinary cork very badly, and soften it so much +that it is necessary to rewire it to prevent it from slipping out. +A rubber stopper is satisfactory and may be used in several runs. + +The evolution of gas is so vigorous that it is not possible to distil +more than 2 l. of the original reaction mixture at one time +in the apparatus described. The connections on the apparatus, +in which the mesitylene is obtained from the crude reaction mixture, +should be tight, since the fumes evolved during the heating +are very irritating. + +The product which distils during the initial heating and the three +minutes of steam distillation is mainly satisfactory material; the rest +of the steam distillation yields only a small amount of pure product. +The two portions of the distillate are, therefore, kept separate, +since the second distillate always contains a considerable amount +of high-boiling product which tends to cause emulsification of +the alkali in the purification. No recovery of acetone is made. + +The mechanism of the reaction is undoubtedly as follows: +when the sulfuric acid and acetone are in contact for long periods +of time, several molecules of the acetone condense to form aldol +condensation products. These do not break down into mesitylene until +the temperature is raised in the second part of the experiment. + +While the original reaction mixture is standing, the temperature +gradually rises to 40'0 or 50'0 in the course of six to ten hours, +and then gradually cools off again. It is probable that at the end +of this time (when the flask has cooled again) the reaction mixture +could be distilled with nearly as good a yield as is obtained +after standing eighteen to twenty-four hours. + +The wide variation in yields which are mentioned in the experimental +part is probably due to a slight change in the grade of the chemicals +which are used in this preparation. 3. Other Methods of Preparation + +The cheapest and most convenient method by which mesitylene may +be prepared is by the action of a dehydrating agent upon acetone; +the agent most commonly used is sulfuric acid.[1] It has been shown +also that phosphoric acid will convert acetone to mesitylene.[2] A number +of other methods have also been used for the preparation of mesitylene: +the action of sulfuric acid on methyl acetylene;[3] the action +of sulfuric acid on mesityl oxide and phorone;[4] the action of +aluminium{sic(british)} chloride on methyl chloride and benzene;[5] +the action of mineral acids upon mesitoyl or benzoyl mesitylene;[6] +the action of phosphoric acid upon diaceto-mesitylene;[7] the treatment +of methylene-3-dimethyl-1, 5-cyclo-hexene-1 with bromine and then +with alcoholic potash.[8] + +[1] Ann. 141, 131 (1867); 147, 43 (1868); 278, 210 (1893); Bud. +soc. chim. (2) 40, 267 (1883); J. prakt. Chem. (1) 15, 129 +(1838); Am. Chem. J. 15, 256 (1893); 20, 807 (1898). + +[2] J Chem. Soc. 99, 1251 (1911). + +[3] Ber. 8, 17 (1875). + +[4] Ber. 7, 1169 (1874); 10, 858 (1877). + +[5] Ber. 12, 329 (1879); Ann. chim. phys. (6) 1, 461 (1884). + +[6] Ber. 32, 1910 (1899). + +[7] Ber. 32, 1563 (1899). + +[8] Ber. 43, 3093 (1910). + + + +XII + +METHYL RED + +(_o_)HO2CC6H>4s>NH2 + HNO2 + HCl-->(_ o_)HO2CC6H4N2Cl + H2O +(_o_) HO2CC6H4N2Cl + C6H5N(CH3)2-->(_ o_)HO2CC6H4N = NC6H4N(CH3)2 + HCl + +Prepared by H. T. CLARKE and W. R. KIRNER. Checked by ROGER ADAMS +and J. B. DAVIS. + +1. Procedure + +TECHNICAL anthranilic acid (generally about 95 per cent pure) +(685 g.) is dissolved in 1.5 l. of water and 500 cc. +of concentrated hydrochloric acid (sp. gr. 1.17), by heating. +The insoluble dark impurity present in small amounts is filtered off, +and the filtrate is transferred to a 10-l. crock and chilled +with stirring. It is then mixed with a mush of 2.5 kg. +of ice and 750 cc. of concentrated hydrochloric acid. The crock +is cooled externally with ice, and the contents stirred continuously. +When the temperature reaches about 3'0, a filtered solution of 360 g. +of sodium nitrite in 700 cc. of water is dropped in slowly, +through a long capillary tube reaching below the surface +of the liquid, until a faint but permanent reaction to starch +potassium iodide paper is obtained; the temperature is kept +between 3'0 and 5'0. This operation requires all but about 30 cc. +of the nitrite solution and occupies one and a half to two hours. +To the solution of the diazonium salt are now added 848 g. +of dimethylaniline; this may be done rapidly, as the temperature +does not rise appreciably. Stirring is continued for one hour, +the temperature being kept at 5'0 Five hundred cc. of a filtered +solution of 680 g. of crystallized sodium acetate diluted to 1200 cc. +are then added, and the stirring continued for four hours. +If a foamy solid rises to the surface during this time and refuses +to become incorporated by the stirrer, a few drops of ethyl acetate may +be added to reduce the foam. The mixture is allowed to stand overnight +in an ice bath which is well insulated by several thicknesses of burlap; +the temperature must be kept below 7'0 to get a good yield of product. +The remainder of the sodium acetate solution is then added +with stirring, and after the mixture has been stirred for an +additional period of one to three hours, the temperature is allowed +to rise slowly to 20-25'0 in the course of twenty-four hours. +Just enough sodium hydroxide solution is then added, with stirring, +to cause the mixture to have a distinct odor of dimethylaniline +(about 240 cc. of a 40 per cent solution are generally required), +and the mixture is allowed to stand for forty-eight hours or longer +at room temperature (20-25'0). + +The solid is then filtered off, washed first with water, then with 400 cc. +of 10 per cent acetic acid (to remove the dimethylaniline) and finally +with distilled water. The last filtrate is generally pale pink. +The solid is sucked as dry as possible, spread out on a tray in order +to allow most of the water to evaporate (fifteen to twenty hours) +and then suspended in 4 l. of methyl alcohol in a 12-l. flask. +This mixture is stirred on the steam bath under a reflux condenser +for one to two hours, allowed to cool slowly, and then chilled in an ice +bath and filtered. The solid product is washed with a second 4 l. +of cold methyl alcohol. After being dried in air, the product +varies in weight from 820 to 870 g. + +The product is extracted with boiling toluene in the following manner: +150 g. are placed in a fluted filter paper of 29 cm. +diameter in a 25-cm. glass funnel which passes through the cork +of a 2-l. flat-bottom conical flask containing 1250 cc. +of toluene (Fig. 2). The flask is heated on an electric stove, +and a 12-l. round-bottom flask is placed on the funnel to act +as a condenser, cold water being run through the flask. +The toluene is boiled until the condensed liquid runs through +almost colorless (this requires from four to ten hours). The heating +is then discontinued, and, as soon as the liquid ceases to boil, +the flask is removed to a bath containing water at 90-100'0; +the level of the water should be slightly above the level +of the liquid in the flask. This arrangement permits the +temperature to fall slowly so that large crystals are obtained. +In the meantime a second conical flask containing 1250 cc. +of toluene is attached to the funnel, and a new charge of 150 g. +of crude methyl red is placed in the paper. When extraction +is complete it is found that a certain amount of black amorphous +insoluble matter remains on the filter; this is discarded. +The crystals of methyl red are filtered off and washed with a +little toluene. The weight of pure material is 755-805 g. +The mother liquors are concentrated to one-fourth of their volume, +and the crystals which separate on cooling are recrystallized +from fresh toluene. The recovered toluene can, of course, +be employed again. The total yield of pure methyl red is 790--840 g. +It melts at 181-182'0. + +The watery mother liquors from the crude methyl red are rendered +alkaline with sodium hydroxide and distilled until no more +dimethylaniline passes over. In this way 250 to 400 g. +of moist dimethylaniline are recovered. + + +2. Notes + +The amount of hydrochloric acid indicated must not be reduced; +otherwise, diazoamino compounds are formed. + +It is essential to keep the temperature low while unreacted diazobenzoic +acid remains in solution, in order to avoid decomposition. +If this precaution is not taken, the yields are considerably diminished, +through the formation of tarry by-products. + +The use of a capillary tube for the addition of sodium nitrite +prevents loss of nitrous acid by local reaction at the surface +of the acid solution. The tube should not be tightly connected +to the dropping funnel, but should be so arranged that air is sucked +through with every drop. In this way, the entrance of the acid +liquor into the capillary is prevented. + +The formation of the azo compound takes place slowly on the addition +of the dimethylaniline, but the speed of the reaction is greatly +increased when the hydrogen ion concentration is lowered +by the addition of the sodium acetate. It is nevertheless +necessary to allow the reaction mixture to stand a long time; +if the product be filtered off after only twenty-four hours, +a further quantity of dye will separate from the filtrate on standing. +The hydrochloride of methyl red is only sparingly soluble in +cold water, and is apt to separate in blue needles if the acidity +is not sufficiently reduced. + +The alcoholic filtrate, obtained on digesting and washing the crude +methyl red, contains a more soluble red by-product which gives +a brownish-yellow solution in alkali. The methyl alcohol may be +recovered with very little loss by distillation; it is, however, +impracticable to attempt to recover any methyl red from the residue, +owing to the tarry nature of the by-product. The proportion of this +by-product is greatly increased if the temperature of the mixture +is allowed to rise too soon after the addition of the sodium acetate. + +Methyl red is described as crystallizing in needles from glacial +acetic acid; on recrystallization from toluene it separates in plates. + +When the methyl red is crystallized from toluene, it sometimes +separates in the form of bright-red lumps, probably on account +of too rapid crystallization. Under these conditions it is advisable +to crystallize again, using a somewhat larger amount of toluene. + +It is advisable to titrate the crude anthranilic acid with standard +alkali and phenolphthalein before starting the experiment. +In checking these directions, an 80 per cent anthranilic acid +was used; it gave a correspondingly lower yield of methyl red +(650-700 g.). The yield of methyl red is about 65 to 70 per cent +based on the dimethylaniline actually used up, but only 58-63 per +cent based on the anthranilic acid actually present in the technical +anthranilic acid employed. + + +3. Other Methods of Preparation + +Methyl red was first prepared[1] by diazotization of anthranilic +acid in alcoholic solution, the product being allowed to react with +dimethylaniline in the same solvent. It has been stated[2] that this +process does not work satisfactorily and yields a different product, +of brownish-red color. + +The preparation of methyl red in aqueous solution has been +described by two workers, one of whom[3] gives but few details +and claims a nearly quantitative yield; the other[4] gives fuller +details and states the yield to be 43.1 per cent of the theory. +The recrystallization of methyl red from toluene is stated[5] +to yield a product melting at 183'0. + +[1] Ber. 41, 3905 (1908). + +[2] Chem. Zentr. 1910, (1), 960; 1910, (11), 1561. + +[3] J. Chem. Soc. 97, 2485 (1910). + +[4] C. A. 14, 3406 (1920) + +[5] J. Chem. Soc. 99, 1334 (1911). + + + +XIII + +_p_-NITROBENZOIC ACID + +(_p_)NO2C6H4CH>3s> + 3O(Na2Cr2O7 + H2SO4)--> (_p_)NO2C6H4CO2H + 3H2O + +Prepared by O. KAMM and A. O. MATTHEWS. Checked by H. T. CLARKE +and W. W. HARTMAN. + +1. Procedure + +IN a 5-l. round-bottom flask, fitted with a mechanical stirrer, +are placed 680 g. of sodium dichromate, 1500 cc. of water, +and 230 g. of _p_-nitrotoluene. Stirring is started, and 1700 g. +of concentrated sulfuric acid are allowed to flow in during about +thirty minutes. The heat of dilution of the sulfuric acid will cause +the nitrotoluene to melt, and rapid oxidation will soon take place. +The last half of the sulfuric acid must be added gradually, +in order to prevent too violent a reaction. Since a small amount +of nitrotoluene is volatilized, it is advisable to carry on this +work under a hood. + +After the sulfuric acid has been added and the spontaneous heating +of the reaction mixture has subsided, the mixture is heated to gentle +boiling for about half an hour. After the reaction mixture has cooled, +2 l. of water are added, the cooled solution is filtered through +a cloth filter, and the product washed with about 1 l. of water. +In order to remove the chromium salts as completely as possible, +the crude nitrobenzoic acid is warmed on the water bath and agitated +with 1 l. of dilute (5 per cent) sulfuric acid solution. +After cooling, the product is again filtered. It is then dissolved +in 5 per cent sodium hydroxide solution, filtered from any chromium +hydroxide remaining, and also from unchanged nitrotoluene. +The filtrate, which should be light yellow or greenish in color, +is acidified with dilute sulfuric acid, with stirring. +It is usually preferable to run the alkaline solution into +the dilute sulfuric acid, rather than to use the reverse procedure, +for the precipitation of the nitro acid. The precipitated product +is filtered with suction, washed thoroughly, and dried. The product +should possess only a light-lemon color. The yield should be 230-240 g. +(80-85 per cent of the theoretical amount). + +For a product of special purity, crystallization from benzene +is advisable. For most purposes, however, the nitrobenzoic acid +may be used without crystallization, since its melting point is found +to be within 2'0 of the correct value of 238'0. + + +2. Notes + +The above procedure differs from that recorded in the literature, +mainly in the use of a fairly large excess of sulfuric acid. +This shortens the reaction time from forty hours to about one hour, +which is especially convenient in the preparation of the acid +on a laboratory scale. Because of the use of this large +excess of sulfuric acid, the reaction is apt to be rather +violent if the directions given are not carefully followed. +The oxidation should be carried out under a hood. Small amounts of +nitrotoluene are lost by volatilization, but this loss is not serious, +as can be seen from the yield of product obtained. + +Ten or 20 g. of unchanged nitrotoluene can be recovered from +the reaction mixture by steam distillation, but the value of +the by-product would not pay for the time spent in recovery. + +The washing of the crude reaction product with dilute sulfuric acid +is advisable, if good material is to be obtained. If an efficient +centrifuge is available for use at this stage of the operation, +this separate washing may prove to be less essential. + +When a sparingly soluble organic acid is precipitated from +fairly concentrated solution, the precipitate is liable +to carry down with it some of the salt of the organic acid. +Addition of the salt solution to the mineral acid, with stirring, +avoids this difficulty. 3. Other Methods of Preparation + +The nitration of benzoic acid produces only very small yields +of the _p_-nitro product.[1] The only practical method for the +preparation consists in the oxidation of _p_-nitrotoluene, although +for this purpose various oxidizing agents are used. In addition +to nitrotoluene, _p_-nitrobenzyl alcohol, _p_-nitrocinnamic acid +and similar compounds may be oxidized, but their cost is prohibitive +in comparison with that of the cheaper nitro hydrocarbon. + +_p_-Nitrotoluene may be oxidized by means of strong nitric acid,[2] +chromic acid mixture,[3] or permanganates.[4] Electrolytic +oxidation[5] has also been proposed. The procedure given above +involves the use of chromic acid mixture, but, owing to a change +in the concentration of sulfuric acid, the time of reaction is greatly +shortened and the preparation is thus considerably improved. + +[1] Ber. 8, 528, 536 (1875) + +[2] Ann. 127, 137 (1863); 128, 257 (1863) + +[3] Ann. 139, 335 (1866). + +[4] J. Am. Chem. Soc. 41, 1575 (1919). + +[5] R. P. 117, 129; Frdl. 6, 112. + + + +XIV _ p_-NITROBENZYL CYANIDE + +C6H5CH2CN + HNO3--> (_p_)NO2C6H4CH2CN + H2O + +Prepared by G. R. ROBERTSON. Checked by ROGER ADAMS and H. O. CALVERY. + +1. Procedure + +IN a 2-l. round-bottom flask, fitted with a stopper holding a dropping +funnel and a mechanical stirrer, is placed a mixture of 275 cc. +of concentrated nitric acid (sp. gr. 1.42) and 275 cc. +of concentrated sulfuric acid (sp. gr. 1.84). This is cooled to 10'0 +in a freezing mixture, and 100 g. of benzyl cyanide (free from alcohol +and water) are run in slowly, at such a rate that the temperature +remains at about 10'0 and does not exceed 20'0. After all the benzyl +cyanide has been added (about one hour), the ice bath is removed, +the mixture is stirred for an hour and then poured on to 1200 g. +of crushed ice. A pasty mass slowly separates; more than half +of this mass is _p_-nitrobenzyl cyanide, the other constituents +being _o_-nitrobenzyl cyanide, and a variable amount of an oil +which resists hydrolysis; apparently no dinitro compounds are formed. +The mass is filtered on a porcelain funnel with suction, pressed well +to remove as much oil as possible, and dissolved in 500 cc. +of boiling alcohol (95 per cent). On cooling, _p_-nitrobenzyl +cyanide crystallizes; the mother liquor, on distillation, +gives an impure alcohol which can be used for the next run. +Recrystallization from 550 cc. of 80 per cent alcohol (sp. gr. +0.86 to 0.87) yields 70 to 75 g. (50-54 per cent) of a product +which melts at 115-116'0. + +This product is satisfactory for most purposes, and incidentally +for the preparation of _p_-nitrophenylacetic acid. Occasionally +it must be free even from traces of the ortho compound, +and in this case should be crystallized again from 80 per cent alcohol; +it then melts at 116-117'0. + + +2. Notes + +Fuming nitric acid may be used in nitrating benzyl cyanide, +but the method here described is cheaper. + +The yield of 70 g. is obtained from benzyl cyanide, which boils +over a 5'0 range prepared as described in preparation III +(p. 9). Very pure benzyl cyanide will give a slightly higher yield, +while commercial grades may give only 50 g. of _p_-nitrobenzyl +cyanide and much oil. + +The reaction has been also carried out with 500 g. +of benzyl cyanide. Under these conditions a 5-l. flask was used, +and it required two and a half hours to add the benzyl cyanide. +The yield of product was 325 to 370 g. + + +3. Other Methods of Preparation + +Nitrobenzyl cyanide has hitherto been prepared by the action +of fuming nitric acid[1] on benzyl cyanide. + +[1] Ber. 17, 505 (1884); 33, 170 (1900); J. Biol. Chem. 39, 585 +(1919); J. Am. Chem. Soc. 43, 180 (1921). + + + +XV + +_p_-NITROPHENYLACETIC ACID + +(_p_)NO2C6H4CN + H2SO4 + 2H2O--> (_p_)NO2C6H4CH2CO2H + NH4HSO4 + +Prepared by G. R. ROBERTSON. Checked by ROGER ADAMS and H. O. CALVERY. + +1. Procedure + +IN a 1-l. round-bottom flask are placed 100 g. of _p_-nitrobenzyl +cyanide. A solution of 300 cc. of concentrated sulfuric acid +(sp. gr. 1.84) in 280 cc. of water is prepared, and two-thirds +of this solution is poured on to the _p_-nitrobenzyl cyanide. +The mixture is shaken well, until the solid is all moistened +with the acid. Any solid material sticking to the walls of +the vessel is now washed down into the liquid with the remainder +of the acid, the flask is attached to a reflux condenser, then set, +without shaking, over a 10-cm. hole in a large sheet of asbestos +board which rests on a tripod, and heated until the mixture boils. +The boiling is continued for fifteen minutes. + +The reaction mixture, which becomes rather dark, is diluted +with an equal volume of cold water and cooled to 0'0 or below. +The solution is filtered, the precipitate is washed several times +with ice water and then dissolved in 1600 cc. of boiling water. +(A few grams of animal charcoal are added in dissolving the precipitate, +if a technical _p_-nitrobenzyl cyanide has been used.) +This solution is filtered as rapidly as possible through a large +folded filter, preferably with a steam funnel. In spite of +all precautions, however, some solid usually separates on the filter. +This must be redissolved in a minimum quantity of boiling water, +and this solution then filtered into the main solution. +The _p_-nitrophenylacetic acid separates in long, pale-yellow needles, +which melt at 151-152'0. The yield is 103 to 106 g. +(92- 3 per cent of the theoretical amount). + + +2. Notes + +If the flask is not protected with an asbestos board or the equivalent, +decomposition occurs where the substance is super-heated on the side +walls of the flask. If crystals of the cyanide are allowed to remain +on the upper walls of the flask, they are not easily washed down +and so are not hydrolyzed. + +The solubility curve of _p_-nitrophenylacetic acid is very steep +at temperatures near 100'0, so that the filtering of the boiling +solution should be rapid. + +If a good grade of cyanide be used, it is not necessary to add +bone-black in order to obtain the acid in a pure state. + +In making experiments with 500 g. of _p_-nitrobenzyl cyanide, +it was found that the time for hydrolysis was about the same as +when smaller amounts were used. + + +3. Other Methods of Preparation + +_p_-Nitrophenylacetic acid has been formed by the nitration of +phenylacetic acid;[1] by the hydrolysis of its ester[2] or its amid,[3] +and by the hydrolysis of its nitrile with hydrochloric acid.[4] + +[1] Ber. 42, 3596 (1909). + +[2] Ber. 12, 1765 (1879). + +[3] Ber. 14, 2342 (1881). + +[4] Ber. 15, 834 (1882). + + + + +XVI + +NITROSO-b-NAPHTHOL + +C10H7OH(b) + HNO2--> C10H6(OH)NO(1,2) + H2O + +Prepared by C. S. MARVEL and P. K. PORTER. Checked by H. T. CLARKE +and W. W. HARTMAN. + +1. Procedure + +IN a 12-l. round-bottom flask fitted with a mechanical stirrer are placed +500 g. of technical b-naphthol dissolved in a warm solution of 140 g. +of sodium hydroxide in 6 l. of water. The solution is cooled +to 0'0 in an ice-and-salt bath, and 250 g. of powdered technical +sodium nitrite is added. Stirring is started and 1100 g. +of sulfuric acid (sp. gr. 1.32) are added from a dropping funnel, +at such a rate that the whole is added in one to one and a half hours, +the temperature being kept at 0'0. During the reaction crushed ice +is added from time to time to maintain the temperature at 0'0; +about 1 kg. is usually used. After all of the sulfuric acid +has been added, the solution should react acid to Congo paper. +The mixture is stirred one hour longer at the low temperature +and then the nitroso-b-naphthol, which has gradually separated out +during the reaction, is filtered with suction and washed thoroughly +with water. The product is at first light yellow in color, +but after three to four days it gradually changes to a dark brown. +The moisture content seems to have some effect on the color. +After the product has been air-dried for about four days, the yield +is about 665 g.; it melts at 97'0. A sample of this partially +dried product, on drying _in vacuo_ over sulfuric acid for twenty hours, +loses about 10 per cent of its weight and the melting point is 106'0. +By longer drying under ordinary conditions, the melting point of 106'0 +is reached. The total yield of dry product is about 595 g. +(99 per cent of the theoretical amount). + +This product is satisfactory for all purposes. It may be obtained +in a crystalline condition, however, by recrystallizing from hot ligroin +(sp. gr. 0.71-0.72). About 2 g. of nitroso-b-naphthol will dissolve +in 15 cc. of boiling ligroin. The product is not very soluble +in cold ligroin, so that nearly all is recovered. + + +2. Notes + +It is very necessary to keep the temperature near 0'0 while +adding the sulfuric acid, or a tarry product will be obtained. +Vigorous stirring and the addition of the sulfuric acid at the proper +rate are essential for a good product. + +A large vessel is needed for the reaction, as the nitroso-b-naphthol +separates in a finely divided condition and there is some +tendency to foam. + +The final air-dried product is pure except for its moisture content, +as is shown by the fact that on drying _in vacuo_ it has a very good +melting point. A sample of Kahlbaum's nitroso-b-naphthol melted +at 101--105. + + +3. Other Methods of Preparation + +Nitroso-b-naphthol has been made by the action of hydroxylamine +hydrochloride on b-naphtho-quinone-chlorimide;[1] by the action +of sulfuric acid upon a solution of potassium or sodium nitrite +and the sodium salt of b-naphthol;[2] by the action of sodium nitrite +upon an alcoholic solution of zinc chloride and b-naphthol;[3] +by the action of sodium nitrite upon b-naphthol suspended in zinc +sulfate solution;[4] by the action of nitrous acid on b-dinaphthol +methane;[5] and by the action of nitrosyl sulfate upon the sodium +salt of b-naphthol.[6] + +[1] Ber. 27, 241 (1894). + +[2] Ber. 8, 1026 (1875); 27, 3076 (1894); J. Chem. Soc. 45, 295 (1884). + +[3] Ber. 18, 705 (1885). + +[4] D. R. P. 25,469; Frdl. 1, 335 (1883). + +[5] Ber. 33, 806 (1900). + +[6] J Chem. Soc. 32, 47 (1877); Ann. 189, 146 (1877). + + + +XVII + +PHENYLACETIC ACID + +C6H5CH2CN + 2H2O + H2SO4--> C6H5CH2CO2H + NH4HSO4 + +Prepared by ROGER ADAMS and A. F. THAL. Checked by O. KAMM and +A. O. MATTHEWS. + +1. Procedure + +IN a 5-l. round-bottom flask, fitted with a mechanical stirrer +and reflux condenser, are mixed 1150 cc. of water, 840 cc. +of commercial sulfuric acid and 700 g. of benzyl cyanide +(preparation III, p. 9). The mixture is heated under a reflux condenser +and stirred for three hours, cooled slightly and then poured into 2 l. +of cold water. The mixture should be stirred so that a solid +cake is not formed; the phenylacetic acid is then filtered off. +This crude material should be melted under water and washed +by decantation several times with hot water. These washings, +on cooling, deposit a small amount of phenylacetic acid which +is filtered off and added to the main portion of material. +The last of the hot water is poured off from the material while it +is still molten and it is then transferred to a 2-l. Claisen +distilling flask and distilled _in vacuo_. A small amount of water +comes over first and is rejected; about 20 cc., containing an +appreciable amount of benzyl cyanide, then distils. This fraction +is used in the next run. The distillate boiling 176-189'0/50 mm. +is collected separately and solidifies on standing. It is practically +pure phenylacetic acid, m. p. 76-76.5'0; it amounts to 630 g. +(77.5 per cent of the theoretical amount). As the fraction which is +returned to the second run of material contains a considerable +portion of phenylacetic acid, the yield actually amounts to at least +80 per cent. + +For the preparation of small quantities of phenylacetic acid, +it is convenient to use the modified method given in the Notes. + + +2. Notes + +The standard directions for the preparation of phenylacetic acid +specify that the benzyl cyanide is to be treated with dilute +sulfuric acid prepared by adding three volumes of sulfuric acid +to two volumes of water. There action, however, goes so vigorously +that it is always necessary to have a trap for collecting +the benzyl cyanide which is blown out of the apparatus. +The use of the more dilute acid, as described in the above directions, +is more satisfactory. + +The phenylacetic acid may also be made by boiling under a reflux +condenser for eight to fifteen hours, without a stirrer, +but this method is not nearly so satisfactory as that described +in the procedure. + +When only small quantities of the acid are required, the following +modified procedure is of value. One hundred grams of benzyl cyanide +are added to a mixture containing 100 cc. of water, 100 cc. +of concentrated sulfuric acid, and 100 cc. of glacial acetic acid. +After this has been heated for forty-five minutes under +a reflux condenser, the hydrolysis is practically complete. +The reaction mixture is then poured into water, and the phenylacetic +acid isolated in the usual manner. + +The odor of phenylacetic acid is disagreeable and persistent. + + +3. Other Methods of Preparation + +The standard method of preparation of phenylacetic acid is by the +hydrolysis of benzyl cyanide with either alkali[1a] or acid.[2a] The acid +hydrolysis runs by far the more smoothly and so was the only one studied. +There are numerous other ways in which phenylacetic acid has been formed, +but none of them is of practical importance for its preparation. +These methods include the following: the action of water on phenyl +ketene;[3a] the hydrolysis and subsequent oxidation of the product +between benzaldehyde and hippuric acid;[1] the reduction of mandelic +acid;[2] the reduction of benzoylformic acid with hydriodic acid +and phosphorus;[3] the hydrolysis of benzyl glyoxalidone;[4] +the fusion of atropic acid with potassium hydroxide;[5] the action +of alcoholic potash upon chlorophenylacetylene;[6] the action +of benzoyl peroxide upon phenylacetylene;[7] the alkaline hydrolysis +of triphenylphloroglucinol;[8] the action of ammonium sulfide +upon acetophenone;[9] the heating of phenylmalonic acid;[10] +the hydrolysis of phenylacetoacetic ester;[11] the action of hydriodic +acid upon mandelonitrile.[12] + + +[1a] Ann. 96, 247 (1855); Ber. 14, 1645 (1881); Compt. +rend. 151, 236 (1910). + +[2a] Ber. 19, 1950 (1886). + +[3a] Ber. 44, 537 (1911). + +[1] Ann. 370, 371 (1909)a + +[2] Chem. (2) 1, 443 (1865); Ber. 14, 239 (1881). + +[3] Ber. 10, 847 (1877) + +[4] J. prakt. Chem. (2) 82, 52, 58 (1910). + +[5] Ann. 148, 242 (1868). + +[6] Ann. 308, 318 (1899). + +[7] J. Russ. Phys. Chem. Soc. 42, 1387 (1910); Chem. Zentr. +1911 (I) 1279. + +[8] Ann. 378, 263 (1911). + +[9 Ber. 21, 534 (1888); J. prakt. Chem. (2) 81, 384 (1910). + +[10] Ber. 27, (1894). + +[11] Ber. 31, 3163 (1898) + +[12] Inaugural Dissertation of A. Kohler (1909), Univ. of Bern. + + + +XVIII + +PHENYLACETYLENE + +C6H5CH=CHBr + KOH--> C6H5CTBCH + KBr + H2O + +Prepared by JOHN C. HESSLER. Checked by J. B. CONANT and E. R. BARRETT. + +1. Procedure + +IN a 500-cc. Pyrex distilling flask are placed 150 g. +of potassium hydroxide. The mouth of the flask is provided with a +one-hole stopper holding a dropping funnel; the side tube of the flask +is connected with a condenser set for downward distillation. +The b-bromostyrene (100 g.) is placed in the dropping funnel. + +The distilling flask is gradually heated in an oil bath until +the temperature of the bath is 200'0, and the bromostyrene is +then dropped in upon the molten potassium hydroxide, at the rate +of somewhat less than a drop a second. Since the boiling point of +phenylacetylene is 142-143'0, and that of bromostyrene is 218-220'0, +the phenylacetylene distils away from the unchanged bromostyrene. + +While the bromostyrene is being dropped in, the temperature +of the oil bath is raised very gradually to 215-220'0, and is kept +at this temperature until all the bromostyrene has been added. +Finally the temperature is raised to 230'0, and is held there +until no more distillate comes over. The distillate is colorless; +it consists of two layers, the lower one being water. +The upper layer is separated and dried with solid potassium hydroxide. +It is then distilled. The yield of the distilled phenylacetylene, +boiling at 142-144'0, is 37 g. (67 per cent of the theoretical +amount). 2. Notes + +Toward the end of the reaction, a crust of potassium bromide +may tend to cover the melted potassium hydroxide. One can break +the crust by shaking the distilling flask gently, or by using +a glass rod inserted through a second hole in the stopper holding +the dropping funnel. + +It is convenient to have such a rod or stirrer passing through +a mercury seal in the stopper of the flask. An occasional turn +of this stirrer breaks the crust and facilitates the operation. +Mechanical stirring should not be employed, as it reduces +the yield tremendously. Apparently this is because it facilitates +the solution of bromostyrene in the tarry by-products and thus causes +it to polymerize instead of reacting with the potassium hydroxide. +A single Pyrex flask can be used for only three or four runs. +The flask should be emptied while still very hot. + +The yield of material can be somewhat increased by working with small lots +(25 g. of bromostyrene). + +The use of steel or copper vessels in place of a glass flask seems +to diminish the yield slightly. + + +3. Other Methods of Preparation + +Phenylacetylene has been prepared by the elimination of carbon +dioxide from phenylpropiolic acid by means of phenol[1] or aniline[2] +or by heating with barium hydroxide;[3] from styrene dibromide, +by heating with potassium hydroxide in alcohol;[4] by heating b-bromo +or chloro styrene with sodium ethylate or potassium hydroxide +in alcohol;[5] by passing the vapors of a-dichloroethylbenzene over +hot soda lime;[6] by the action of alcoholic potassium hydroxide +on dibenzal-acetone tetra-bromide;[1b] by the action of aqueous +potassium hydroxide on phenyl propargylaldehyde;[2b] by the action +of molten potassium hydroxide on b-bromo-styrene.[3b] + + +[1] Ber. 20, 3081 (1887). + +[2] Rec. trav. chim. 16, 157 (1896). + +[3] Arm. 221, 70 (1883). + +[4] Ann. 154, 155 (1870); 235, 13 (1886); Bull. soc. chim. 35, 55 +(1881); (3) 25, 309 (1901). + +[5] Ann. 308, 265 (1899); 342, 220 (1905). + +[6] Jahresb. 1876, 308; Gazz. chim. ital. 22 (2), 67 +(1892); Bull. soc. chim. (3) 25, 309 (1901). + +[1b] Ber. 39, 4146 (1900). + +[2b] Ber. 31, 1023 (1898). + +[3b] J. Am. Chem. Soc. 44, 425 (1922). + + + +XIX + +PHENYLHYDRAZINE + +C6H5NH2<.>HCl + NaNO2 + HCl--> C6H5N2Cl + NaCl + 2H2O C6H5N2Cl ++ 4H(Na2SO3)--> C6H5NHNH2<.>HCl + +Prepared by G. H. COLEMAN. Checked by J. B. CONANT and H. R. THOMPSON. + + +1. Procedure + +IN a 12-l. round-bottom flask, fitted with a mechanical stirrer, +are placed 1045 cc. of concentrated commercial hydrochloric acid +(sp. gr. 1.138). The flask is surrounded with a freezing mixture +of ice and salt, and when the contents are at 0'0, stirring is started +and 500 g. of cracked ice are added; then 372 g. of aniline, +also cooled to 0'0, are run in during five minutes. The mixture +is treated with 500 g. more of cracked ice, and a cold solution +(0'0) of 290 g. of technical sodium nitrite dissolved in 600 cc. +of water are allowed to run in slowly (twenty to thirty minutes) +from a dropping funnel, the end of which is drawn to a small tip, +and reaches nearly to the bottom of the flask. During this addition, +the stirrer is operated rather vigorously, and the temperature is +kept as near 0'0 as possible by the frequent addition of cracked ice +(about 1 kg). + +In the meantime, a sodium sulfite solution is prepared by dissolving +890 g. of sodium hydroxide, of about 90 per cent purity, in about 1 l. +of water and then diluting to 6 l. A few drops of phenolphthalein +solution are added and sulfur dioxide passed in, first until an acid +reaction is indicated and then for two or three minutes longer. +During the addition of the sulfur dioxide, the solution is cooled +with running water. On account of the strong alkaline solution, +the original color produced by the phenolphthalein is very faint, +but this slowly increases until it becomes deep just before the acid +point is reached. It is best to remove a small sample of the liquid +from time to time, dilute with three or four volumes of water +and add a drop more of phenolphthalein. + +The sodium sulfite solution is placed in a 12-l. flask and cooled +to about 5'0. Approximately 500 g. of cracked ice are added, and then, +with mechanical stirring, the diazonium salt solution is run in as +rapidly as possible. The mixture becomes a bright orange-red. The +flask is now warmed to about 20'0 on a steam bath, until the solid +sodium sulfite, which has separated while cooling, redissolves. +The total amount of liquid is now about 10 l. One-half of this +is poured into another 12-l. flask, and both halves are warmed +on the steam bath to 60-70'0, until the color becomes quite dark +(thirty to sixty minutes). Sufficient hydrochloric acid (300-400 cc.) +is now added to each flask to make the solutions acid to litmus. +The heating is continued and the color gradually becomes lighter until, +after four to six hours, the solutions have become nearly colorless; +they may be heated overnight, if desired. + +To the hot solutions are now added about one-third of their volume +of concentrated hydrochloric acid (2 l. to each portion) and the +mixtures cooled, first in running water, then in a freezing mixture, +to 0'0. The phenylhydrazine hydrochloride precipitates in the form +of slightly yellowish or pinkish crystals which may be filtered +off and dried. + +The free base is liberated by adding to the phenylhydrazine +hydrochloride 1 l. of a 25 per cent solution of sodium hydroxide. +The phenylhydrazine separates and is taken up with benzene +(two 300-cc. portions). The combined extractions are well dried +with 200 g. of solid sodium hydroxide, poured off, and distilled. +Most of the benzene may be distilled under ordinary pressure, +and the remainder, and any low-boiling impurities, +under diminished pressure. The pure phenylhydrazine boils +at 137-138'0/18 mm., and is obtained as a pale-yellow liquid. +It can be crystallized on cooling in an ice bath; the crystals +melt at 230. The crude phenylhydrazine from two lots of aniline +(744 g.) is best distilled at one time and gives 695-725 g. +of pure product (80-84 per cent of the theoretical amount). + + +2. Notes + +If the sodium sulfite solution contains an excess of alkali, +a black tar tends to form when the solution is warmed, and very +little phenylhydrazine is obtained. Great care must be taken +in determining the end point in the neutralization of the sodium +hydroxide by the sulfur dioxide. + +If the sodium sulfite-diazonium salt mixture is acidified before +warming or before becoming dark, the red color of the solution does +not disappear on heating, and the precipitated phenylhydrazine +hydrochloride obtained is colored red. + +The benzene solution of phenylhydrazine should be well dried +before distilling, since the presence of moisture causes an increased +amount of foaming to take place just after the benzene has distilled off. +When the distillation is carried out carefully, practically no +phenylhydrazine distils with the benzene or other low-boiling impurities. + +In order to obtain the maximum yield, it is necessary to cool the +hydrochloric acid solution of the phenylhydrazine hydrochloride from 20'0 +to 0'0, before filtration. From 5 to 10 per cent of product separates +between these two temperatures. When this is done, no more phenylhydrazine +hydrochloride is obtained by concentration of the mother liquor. +An increase in the amount of hydrochloric acid above 2 l. +for the precipitation of the hydrochloride produces no increase +in yield of product. + +Most published directions for the preparation of phenylhydrazine +specify the use of zinc dust and acetic acid following the reduction +with sodium sulfite. No improvement in the quality or quantity +of the product was obtained by using zinc and acetic acid. + +It is best to use freshly prepared sodium sulfite for the reduction, +since the commercial quality is poor and gives a lower yield +of phenylhydrazine. A cylinder of liquid sulfur dioxide should, +of course, be available. + +The rapid addition of the diazonium salt solution to the sodium +sulfite seems to be advantageous. + +Pure phenylhydrazine dissolves in dilute acetic acid to yield +a perfectly clear solution. + +The phenylhydrazine hydrochloride may be purified by crystallizing +from water. A 600-cc. portion of water is used for 100 g. +of crude hydrochloride, and the solution boiled a short time +with a few grams of animal charcoal. After filtering, 200 cc. +of concentrated hydrochloric acid are added, and the mixture cooled +to 0'0. Pure white crystals in a yield of 85-90 g. are obtained. + +Rubber gloves should be worn when working with large quantities +of phenylhydrazine, since the product may cause serious injury +to the skin. The vapors of phenylhydrazine should not be inhaled. + + +3. Other Methods of Preparation + +Phenylhydrazine has been prepared by the reduction of benzene diazonium +salts with sulfites;[1] by the reduction of benzene diazonium +chloride with stannous chloride;[2] by the reduction of benzene +diazonium hydrate with zinc or sulfur dioxide;[3] by the reduction +of sodium benzene diazotate with sodium stannite;[4] by the reduction +of diazoamino benzene;[5] by the reduction of nitrosophenyl +hydroxylamine or its methyl ether;[6] and by the action of hydrazine +hydrate on phenol.[7] + + +[1] Ann. 190, 79 (3878); Ber. 20, 2463, (1887). + +[2] Ber. 16, 2976 (1883); 17, 572, footnote (1884). + +[3] Ber. 31, 346 (1898). + +[4] Ber. 36, 816 (1903). + +[5] Ber. 31, 582 (1898). + +[6] Ann. 190, 77 (1878). + +[7] Ber. 31, 2910 (1898). + + +The most feasible method consists in the reduction of diazonium +salts with sodium sulfite. Although this method is given in several +laboratory manuals, the results were not found entirely satisfactory. +The present directions provide for a lengthy but essential +heating of the diazonium-sulfite mixture, omit the useless zinc +dust reduction, and supply exact details for preparation on a fairly +large laboratory scale. + + + +XX + +PHTHALIMIDE CO CO C6H4< >O + NH4OH--> C6H4< >NH + 2H2O + CO CO + CO CO +2C<6s<H<s>4< >O + (NH4)2CO3--> 2<C6H4< >NH + CO2 + 3H2O CO CO + +Prepared by W. A. NOYES and P. K. PORTER. Checked by H. T. CLARKE +and J. H. BISHOP. + +1. Procedure + +IN a 5-l. round-bottom flask (Pyrex) is placed a mixture of 500 g. +of phthalic anhydride and 400 g. of 28 per cent ammonium hydroxide. +The flask is fitted with an air condenser not less than 10 mm. +in diameter and is then slowly heated with a free flame until the mixture +is in a state of quiet fusion at a temperature of about 300'0. It +requires about one hour before all the water has gone and about +one and a half to two hours before the temperature of the reaction +mixture reaches 300'0 and the mixture is a homogeneous melt. +It is advisable, during the heating, to shake the flask occasionally; +some material sublimes into the condenser and must be pushed +down with a glass rod. The hot reaction mixture is now poured out +into a crock, covered with a paper to prevent loss by sublimation, +and allowed to cool. The product is practically pure without +further treatment, and melts at 232-235'0. The yield is 470-480 g. +(94-95 per cent of the theoretical amount). + +Phthalimide may also be made by using 500 g. of phthalic anhydride +and 500 g. of ammonium carbonate which has been previously ground +in a mortar. The subsequent procedure is the same as when aqueous +ammonia is used. Frequent shaking is necessary, and the sublimed +material must be occasionally pushed back into the reaction flask. +About two hours are required for completion. + + +2. Notes + +Several smaller runs of 25 g. of phthalic anhydride gave +the same percentage yield. + +Phthalimide may be recrystallized from water, but only about 4 g. +of phthalimide will dissolve in a liter of boiling water. +It may also be crystallized from alcohol, in which solvent it dissolves +to the extent of five parts in a hundred at boiling temperature. + +On a large scale, it would be advisable to collect the small amount +of ammonia given off during the reaction. + +If desired, the product obtained by pouring the reaction mass +into the crock may be treated with hot water to soften the cake, +broken up with a glass rod, transferred to a flask and boiled with water +for a few minutes. This treatment, however, is quite unnecessary; +for all practical purposes, the crude cake, as it is obtained, +may be ground up and used directly. + + +3. Other Methods of Preparation + +Phthalimide has been formed by heating ammonium phthalate;[1] +by heating acid ammonium phthalate;[2] by passing dry ammonia over +heated phthalic anhydride;[3] by treating phthalyl chloride with dry +ammonia;[4] by heating phthalamide;[5] by heating phthalic anhydride +with ammonium thiocyanate;[6] by heating phthalic anhydride with +urea;[7] by heating phthalic anhydride with ammonium carbonate;[1b] +by heating phthalic acid with nitriles;[2b] by fusing _o_-cyanobenzoic +acid;[3b] and by the action of potash on _o_-cyanobenzaldehyde.[4b] + + +[1] Jahresb. 1868, 549; Ann. 19, 47 (1836); 41, 110 (1842); 42, 220 +(1842); 205, 300 (1880); 215, 181 (1882). + +[2] Jahresb. 1847-1848, 590. + +[3] Am. Chem. J. 3, 29 (1881). + +[4] Am. Chem. J. 3, 28 (1881). + +[5] Ber. 39, 2278 (1906). + +[6] Ber. 19, 1398 (1886), + +[7] Ber. 10, 1166 (1877); Am. Chem. J. 18, 333 (1896); +J. Am. Chem. Soc. 32, 116 (1910); Z. angew. Chem. 32, I, 301 (1919). + +[1b] J. Am. Chem. Soc. 42, 1282 (1920). + +[2b] J Am. Chem. Soc. 18, 680 (1896); 20, 654 (1898). + +[3b] Rec. trav. chim. (I) 11, 93 (1892). + +[4b] Ber. 30, 1698 (1897). + + +Of these, the first three are the only ones which need be +considered as methods for the preparation of phthalimide. +It was found that the third was by no means easy to bring about: +dry phthalic anhydride is apparently only superficially affected +by the dry ammonia, and it was difficult to introduce sufficient heat +into the loose mass of crystals to cause the reaction to start. + + + + +XXI + +QUINOLINE + +/ \ / \ C3H5(OH)3 + C6H5NH2 + 4O(C6H5NO2)--> | | | + 4H2O \ / \n/ + +Prepared by H. T. CLARKE and ANNE W. DAVIS. Checked by ROGER ADAMS +and A. W. SLOAN. + +1. Procedure + +IN a 5-l. round-bottom flask, fitted with an efficient reflux +condenser of wide bore, are placed, in the following order, 80 g. +of powdered crystalline ferrous sulfate, 865 g. of glycerol +(c. p.), 218 g. of aniline, 170 g. of nitrobenzene, and 400 cc. +of concentrated sulfuric acid (sp. gr. 1.84). The contents of the flask +are well mixed and the mixture heated gently over a free flame. +As soon as the liquid begins to boil, the flame is removed, since the heat +evolved by the reaction is sufficient to keep the mixture boiling +for one-half to one hour. If the reaction proceeds too violently at +the beginning, the reflux condenser may be assisted by placing a wet +towel over the upper part of the flask. When the boiling has ceased +the heat is again applied and the mixture boiled for five hours. +It is then allowed to cool to about 100'0 and transferred to a 12-l. flask; +the 5-l. flask is rinsed out with a small quantity-of water. +The 12-l. flask is then connected with the steam-distillation +apparatus shown in Fig. 3, a 12-l. flask being used as a receiver; +steam is passed in (without external heat) until 1500 cc. +have distilled (ten to thirty minutes). This removes all +the unchanged nitrobenzene (10-20 cc.). The current of steam +is then interrupted, the receiver is changed, and 1500 g. +of 40 per cent sodium hydroxide solution are added cautiously +through the steam inlet. The heat of neutralization is sufficient +to cause the liquids to boil and thus become thoroughly mixed. +Steam is then passed in as rapidly as possible until all the quinoline +has distilled. In this process, 6-8 l. of distillate are collected +(two and a half to three and a half hours are required, unless a +very efficient condensing apparatus is used, under which conditions +the distillation may be complete in one-half to one and a half hours). +The distillate is allowed to cool, and the crude quinoline separated. +The aqueous layer of the distillate is again distilled with steam +until all the quinoline has been volatilized and collected in about +3 l. of distillate. + +These 3 l. of distillate are then mixed with the first yield of quinoline +and 280 g. (150 cc.) of concentrated sulfuric acid are added. +The solution is cooled to 0-5'0, and a saturated solution of sodium +nitrite added until a distinct excess of nitrous acid is present +(as shown either by starch-potassium iodide paper or by the odor). +This generally requires 50 to 70 g. of sodium nitrite. +The mixture is then warmed on a steam bath for an hour, or until +active evolution of gas ceases, and is then distilled with steam +until all the volatile material has been expelled (41. of distillate +will result) The receiver is then changed and the mixture in +the distillation flask is neutralized, as before, with 700 g. +of 40 per cent sodium hydroxide solution. The quinoline is distilled +exactly as described above, the aqueous portions of the distillate +being distilled with steam until all the quinoline has been isolated. +The crude product is then distilled under reduced pressure, +and the fraction which boils at 110-114'0/14 mm. is collected. +The foreruns are separated from any water which may be present, dried with +a little solid alkali, and redistilled. The total yield is 255-275 g. +(84-91 per cent of the theoretical amount based on the aniline taken). + + +2. Notes + +Although these directions have been used many times with results +exactly as described, in a few cases the yields have dropped to 60-65 +per cent without any apparent reason. At present no explanation +can be given for this. + +In the Skraup synthesis of quinoline the principal difficulty has +always been the violence with which the reaction generally takes place; +it occasionally proceeds relatively smoothly, but in the majority +of cases gets beyond control, with consequent loss of material +through the condenser. By the addition of ferrous sulfate, +which undoubtedly functions as an oxygen carrier, the reaction +is extended over a longer period of time. It is thus possible +to work with much larger quantities of material when ferrous +sulfate is employed. + +It is important that the materials should be added in the correct order; +should the sulfuric acid be added before the ferrous sulfate, +the reaction may start at once. It is also important to mix +the materials well before applying heat; the aniline sulfate should +have dissolved almost completely and the ferrous sulfate should be +distributed throughout the solution. To avoid danger of overheating, +it is well to apply the flame away from the center of the flask +where any solids would be liable to congregate. + +In the apparatus for steam distillation, the greater portion +of the condensation is effected by the stream of water passing +over the receiver. It is, therefore, necessary that the stream +passing through the condenser should be sufficiently rapid to cause +it to form a uniform film over the receiving flask. A 12-l. flask +is even more efficient as a condenser than the 5-l. flask. It is +important that the tube through which the vapors leave the distillation +flask should be neither too short nor, especially, too narrow. +Where the external diameter of the steam inlet tube is 5-8 mm., +the internal diameter of this steam head should be not less than 28 mm. +Were it less, the current of steam passing through it would be so rapid +as to prevent small quantities of liquid from returning to the flask, +and these would be driven over into the receiver. + +Much time can be saved by the use of the steam distillation apparatus +described, especially when large quantities have to be handled. +The above directions avoid the use of extraction methods, which not +only consume more time but may lead to appreciable losses of material. +If the downward condenser is of iron, the apparatus is even more +efficient and the time for the steam distillation is halved. + +The percentage yields have been based on the amount of aniline taken. +It would probably be more legitimate to base the calculation on the amounts +of aniline taken and of nitrobenzene not recovered, since undoubtedly +the latter is reduced to aniline during the course of the reaction. +If this be done, the yield is found to be only 55 to 60 per cent +of the calculated amount. + +In a number of experiments, the glycerol used contained an appreciable +amount of water. Under these conditions, the yield of product +is much lower. "Dynamite" glycerol containing less than half a per +cent of water is best employed; U. S. P. glycerol contains 5 per +cent of water and usually gives lower yields. + + +3. Other Methods of Preparation + +Quinoline has been produced by passing the vapor of allylaniline +over red-hot lead oxide;[1a] by heating acrylideneaniline, or better, +a mixture of aniline, glycerol and sulfuric acid;[2a] by heating +aniline with glycerol and sulfuric acid, using nitrobenzene as an +oxidizing agent;[1] by treating a mixture of glyoxal and _o_-toluidine +with alkali;[2] by treating a solution of _o_-aminobenzaldehyde with +acetaldehyde and alkali;[3] by heating methylacetanilide with zinc +chloride;[4] by heating aminoazobenzene with glycerol and sulfuric +acid;[5] by heating a mixture of aniline, glycerol and sulfuric +acid with arsenic acid.[6] + + +[1a] Ber. 12, 453 (1879). + +[2a] Ber. 13, 911 (1880); Monatsh. 1, 316 (1880). + +[1] Monatsh. 2, 141 (1881); J. prakt. Chem. (2) 49, 549 (1894), + +[2] Monatsh. 15, 277 (1894). + +[3] Ber. 15, 2574 (1882); 16, 1833 (1883). + +[4] Ber. 23, 1903 (1890). + +[5] Ber. 24, 2623 (1891) + +[6] Ber. 29, 704 (1896) + + +Of the above methods, the only ones which need be considered are +those in which a mixture of aniline, glycerol and sulfuric acid +is heated with an oxidizing agent. With the use of nitrobenzene, +the reaction, according to the original method, takes place +with extreme violence. + +The method above described is the most satisfactory for the preparation +of quinoline itself, but for the preparation of homologues +of quinoline, the use of arsenic acid is preferable, since the yields +are somewhat greater. + +Since the work was carried out, a method has been published[7] in +which aniline, glycerol and sulfuric acid are treated with ferric oxide. +By this method Adams and Parks were unable to obtain yields comparable +with those resulting from the above directions. + +[7] Chem. News 121, 205 (1920). + + + + +XXII + +QUINONE + +(1)HOC6H4OH(4) + O(Na2Cr2O7 + H2SO4)--> O=C6H4=O + H2O Prepared +by E. B. VLIET. Checked by ROGER ADAMS and E. E. DREGER. + + +1. Procedure + +IN a 2.5-l. beaker, 100 g. of hydroquinone are dissolved +in 2000 cc. of water heated to about 50'0. After the solid +is completely dissolved, the solution is cooled to 20'0, 100 g. +of concentrated sulfuric acid are slowly poured in, and the mixture +is again cooled to 20'0. A concentrated solution of technical sodium +dichromate is prepared by dissolving 140 g. in 65 cc. of water. +This solution is then added gradually to the hydroquinone solution, +with the use of a mechanical stirrer (see notes), the mixture being +cooled so that the temperature never rises above 30'0. At first +a greenish-black precipitate forms, but upon further addition of +the sodium dichromate solution, the color changes to yellowish green. +As soon as this color remains permanent (a slight excess +of sodium dichromate does no harm) the reaction is complete. +This requires about one-half to three-quarters of an hour; +90 to 110 cc. of sodium dichromate solution is necessary. +The mixture is then cooled to about 10'0 and filtered with suction. +As much water as possible is pressed out of the crystals. + +The filtrate is extracted twice, 150 cc. of benzene being used +for each extraction. The precipitate of quinone is transferred +to a 1-l. beaker, and 500 cc. of benzene, including the 300 cc. +used to extract the filtrate, are added, The mixture is now heated +with stirring on a steam-bath, and as soon as most of the quinone +has dissolved the benzene layer is decanted into another beaker. +It is dried while hot by stirring a short time with a little +calcium chloride, and then filtered through an ordinary funnel +into a 1-l. distilling flask before it cools. There is a certain +amount of quinone which does not go into the 500 cc. of benzene, +so that the residue is extracted a second time with about 100 cc. +of benzene, which is dried and filtered with the first extract. +During these extractions, the benzene should not be at the boiling point, +as this will cause a considerable volatilization of the quinone. + +The distilling flask is now attached to a condenser set +for downward distillation, and the benzene is distilled. +As soon as the quinone starts to separate, the residue in the flask +is transferred to a beaker and cooled in an ice bath. The precipitate +is filtered off with suction and the product spread out for a short +time to dry. The product is yellow in color and weighs 75 to 80 g. +(76-81 per cent of the theoretical amount). Material made in this way +will hold its yellow color over long periods of time, provided it +is protected from light. + +The benzene distillate is yellow and contains some quinone. +This, as well as the benzene from the final filtration of +the quinone crystals, may be used in a subsequent run and thus +raises the yield of the subsequent runs to about 85-90 g. +(85-90 per cent of the theoretical amount). + + +2. Notes + +As the mixture becomes thick during the oxidation, it is very necessary +to use a stirrer which will keep the whole mass agitated by reaching +to the sides and bottom of the beaker. + +If impure hydroquinone is used, a black, sticky precipitate will +usually appear after the addition of the sulfuric acid to the +hydroquinone solution. This should be removed, before the oxidation +is started, by filtration without suction through a fluted filter. + +When technical sodium dichromate is used, the solution should be +filtered with suction, before it is added to the hydroquinone, +in order to remove any insoluble impurities. + +In the laboratory it is convenient to make several small runs +of the size indicated, as far as the oxidation is concerned; +but the benzene extractions can be combined. + +It is also possible to obtain good yields of quinone in the +following manner: 1500 cc. of water, 465 g. of concentrated +sulfuric acid and 300 g. of hydroquinone are mixed in a 3-l. beaker. +The mixture is cooled to 0'0, and 330 g. of sodium dichromate are added +in powdered form, the temperature being kept below 5'0 at all times. +This procedure requires a longer time and much more care in the control +of conditions than the method described above. + + +3. Other Methods of Preparation + +Quinone may be prepared by the oxidation of aniline with +dichromate or manganese dioxide and sulfuric acid.[1] This +is a more feasible commercial method than the one given. +However, the oxidation of hydroquinone is more rapid and +convenient and, hence is more desirable for use in the laboratory. +Various materials have been oxidized by chemical means to give quinone: +they are quinic-acid,[2] hydroquinone,[3] benzidine,[4] +_p_-phenylenediamine,[5] sulfanilic acid,[6] _p_-phenolsulfonic +acid,[7] arbutin,[8] aniline black,[9] and the leaves of various +plants.[10] Quinone is also formed by several other methods: +by the fermentation of fresh grass;[11] by the action of iodine +on the lead salt of hydroquinone;[1b] by the decomposition +of the compound, C6H4<.>2CrO2Cl with water;[2b] by the action of +sulfuric acid on phenol blue;[3b] by the electrochemical oxidation +of aniline,[4b] hydroquinone[5b] or benzene;[6b] by the catalytic +oxidation of benzene.[7b] + + +[1] Jahresb. 1863, 415; Ber. 10, 1934, 2005 (1877); 16, 687 +(1883); 19, 1468 (1886); 20, 2283 (1887); 31, 1524 (1898); Ann. +200, 240 (1880); 215, 127 (1882). + +[2] Ann. 27, 268 (1838). + +[3] Ann. 51, 152 (1844) j Am. Chem. J. 14, 555 (1892). + +[4] Jahresb. 1863, 415. + +5 Jahresb. 1863, 422. + +6 Ann. 159, 7 (1871); Ber. 8, 760 (1875). + +[7] Ber. 8, 760 (1875). + +[8] Ann. 107, 233 (1858). + +[9] Ber. 10, 1934 (1877); 34, 1285 (1901). + +[10] Ann. 89, 247 (1854); Ber. 34, 1162 (1901). + +[11] Ber. 30, 1870 (1897). + +[1b] Ber. 31, 1458 (1898); Am. Chem. J. 26, 20 (1901). + +[2b] Ann. chim. phys. (5) 22, 270 (1881). + +[3b] Ber. 18, 2915 (1885); 21, 889 (1888). + +[4b] D. R. P. 109,012; Frdl. 5, 664 (1900); D. R. P. 117,129; Frdl. +6, 112 (1901); J. Soc. Dyers and Colourists, 36, 138 (1920). + +[5b] D. R P. 117,129; Frdl. 6, 112 (1901). + +[6b] D. R. P. 117,251; Frdl. 6, 109 (1901); U. S. Pat. +1,322,580 (1919); C. A. 14, 287 (1920); Rev. produits chim. +21, 219 (1918); 21, 288 (1918). + +[7b] U. S. Pat. 1,318,631 (1919); C. A. 14, 70 (1920). + + + +XXIII + +SODIUM _p_-TOLUENESULFINATE + +2CH3C6H4SO2Cl + 3Zn--> (CH3C6H4SO2)2Zn + ZnCl2 (CH3C6H4SO2)2Zn + +Na2CO3--> 2CH3C6H4SO2Na + ZnCO3 + +Prepared by FRANK C. WHITMORE and FRANCIS H. HAMILTON Checked +by J. B. CONANT and PAUL ALLEN, JR. + + +1. Procedure + +FIVE HUNDRED grams of technical _p_-toluenesulfonyl chloride are ground +in a mortar to break up all lumps. Three liters of water are placed +in a 12-l. crock provided with a large brass stirrer and a tube +for passing steam directly into the liquid. Dry steam is passed +into the water until the temperature reaches 70'0. The steam is then +shut off and 400 g. of zinc dust (90 to 100 per cent pure) is added. +The sulfonyl chloride is then added in small portions by means +of a porcelain spoon. The addition takes about ten minutes. +The temperature rises to about 80'0. Stirring is continued +for ten minutes after the last of the chloride has been added. +Steam is then passed into the mixture until the temperature +reaches 90'0. If it is heated any hotter, bumping takes place. +The steam is shut off, and 250 cc. of 12 _N_. sodium hydroxide +solution is added. Finely powdered sodium carbonate is then +added in 50-g. portions until the mixture is strongly alkaline. +The mixture froths considerably, but this causes no trouble unless +too small a crock is used. The stirrer is loosened and the crock +is removed. The mixture is filtered by suction in a large funnel. +The filtrate has a volume of about 4.5 l. The cake of unchanged +zinc dust and zinc compounds is transferred to a 3-l. battery jar +and placed under the stirrer, and the latter is clamped in place. +Water (750 cc.) is added, the stirrer is started, and steam +is passed in until the mixture starts to froth too violently. +The steam is then shut off, but the stirring is continued +for ten minutes. The mixture is filtered and the filtrate +is added to the main solution in a large evaporating dish. +The liquid is evaporated over a large burner to a volume of about +1 l., or until a considerable crust forms around the edges. +The mixture is then cooled. Large, flat, transparent crystals separate. +The thoroughly cooled mixture is filtered by suction, +and the crystals are air-dried until efflorescence just starts. +They are then bottled. The product is CH3C6H4SO2Na<.>2H2O. Yield 360 g. +(64 per cent of the theoretical amount). Careful acidification +of the mother liquor with dilute hydrochloric acid yields 15 g. +of the free sulfinic acid. + + +2. Notes + +The free sulfinic acid may be prepared by dissolving the sodium salt in +cold water and carefully acidifying the solution with hydrochloric acid. +An excess of the latter must be avoided, as it dissolves the acid +to a certain extent. The sulfinic acid is difficult to dry without +partial conversion into the sulfonic acid. + + +3. Other Methods of Preparation + +Toluenesulfinic acid and its salts have been prepared by three +general methods: (1) The reduction of the sulfonyl chloride. +The reagents which have been used for this are sodium amalgam,[1] zinc +dust in alcohol or water,[2] sodium sulfite,[3] sodium sulfide,[4] +potassium hydrosulfide[5] (the thio acid being first formed) +and sodium arsenite.[6] (2) From toluene by the Friedel and +Crafts reaction, using either sulfur dioxide and hydrogen chloride[7] +or sulfuryl chloride.[8] (3) From _p_-toluidine by diazotization +and subsequent treatment with sulfur dioxide and finely divided +copper.[1b] The compound has also been obtained in certain +reactions which, however, would not be suitable for preparative work; +thus it is formed by hydrolysis and reduction of certain thio +derivatives[2b] prepared from the acid itself and also by the +decomposition of ditolylsulfonmethylamine.[3b] + + +[1] Ann. 142, 93 (1867). + +[2] Ber. 9, 1586 (1876). + +[3] Ber. 3, 965 (1870). + +[4] D. R. P. 224,019; Chem. Zentr. 1910, (II), 513. + +[5] Ber. 42, 3821 (1909). + +[6] Ber. 41, 3351 (1908); Ber. 42, 480 (1909). + +[7] Ber. 41, 3318 (1908); J. Chem. Soc. 93, 754 (1908). + +[8] Rec. trav. chim. (2) 30, 381 (1911). + +[1b] Ber. 32, 1141 (1899); J. Chem. Soc. 95, 344 (1909). + +[2b] Ber. 15, 130 (1882); 20, 2088 (1887); 41, 3351 (1908). + +[3b] J. prakt. Chem. (2) 63, 170 (1901). + + + +XXIV + +1,3,5-TRINITROBENZENE + +C6H2(NO2)3CO2H--> C6H3(NO2)3 + CO2 + +Prepared by H. T. CLARKE and W. W. HARTMAN. Checked by J. B. CONANT +and J. J. TOOHY. + +1. Procedure + +THE crude trinitrobenzoic acid obtained by oxidation of 360 g. +of trinitrotoluene (prep. XXV, p. 95) is mixed with 2 l. +of water at 35'0 in a 5-l. flask provided with a stirrer. +Fifteen per cent sodium hydroxide solution is added, +with continuous stirring, until a FAINT red color is just produced. +(See Notes.) The color is then immediately discharged by means +of one or two drops of acetic acid, and the liquid is filtered +from unchanged trinibrotoluene. The filtrate is transferred +to a 5-l. flask, and 70 cc. of glacial acetic acid are added. +The mixture is then gently heated, with continuous stirring, +when trinitrobenzene separates in crystalline condition, +and floats on the surface of the liquid as a frothy layer. +After about one and a half hours the evolution of gas ceases; +at this point the crystals begin to stir into the solution. +The heating and stirring is continued for three-quarters of an hour, +when the mixture is allowed to cool, and the crystals filtered off. +A sample of the filtrate should be tested for undecomposed +trinitrobenzoic acid: if a precipitate is produced by +the addition of sulfuric acid the process must be continued. +After recrystallization from glacial acetic acid, the product +melts at 121-122'0. The yield is 145-155 g. (43 to 46 per cent +of the theoretical amount calculated from the trinitrotoluene). 2. +Notes + +During the solution of the trinitrobenzoic acid, the temperature should +not be below 35'0, owing to the slight solubility of trinitrobenzoic +acid in cold water. The heat of neutralization raises the temperature +to 45-55'0, but the latter temperature should not be exceeded, +since any trinitrobenzene formed at this point would later be removed +with the unreacted trinitrotoluene. + +Care must be taken that no more alkali is added than is just sufficient +to produce the faint red color. If an excess of alkali is added it +produces a permanent color, which is not removed by acid and colors +the final product. + +When once the evolution of carbon dioxide sets in, the flame must +be cut down so as to avoid the formation of a thick layer of froth +which might foam over. + + +3. Other Methods of Preparation + +1,3,5-Trinitrobenzene can be prepared by heating _m_-dinitrobenzene +with nitric acid and sulfuric acid to 120'0;[1] by heating +2,4,6-trinitrotoluene with fuming nitric acid in a sealed tube +at 180'0 for three hours;[2] by heating 2,4,6-trinitrobenzoic acid +or its sodium salt with water, alcohol, dilute sodium carbonate +or other suitable solvent.[3] + + +[1] Ber. 9, 402 (1876); Ann. 215, 344 (1882). + +[2] Ber. 16, 1596 (1883). + +[3] D. R. P. 77,353; Frdl. 4, 34 (1894). + + + +XXV + +2, 4, 6-TRINITROBENZOIC ACID + +C6H2(NO2)3CH3 + 3O(Na2Cr2O7 + H2SO4)--> C6H2(NO2)3CO2H + H2O + +Prepared by H. T. CLARKE and W. W. HARTMAN. Checked by J. B. CONANT +and J. J. TOOHY. + +1. Procedure + +To 3600 g. of concentrated sulfuric acid, in a 5-l. flask placed +in an empty water bath, are added 360 g. of technical trinitrotoluene, +while the mixture is stirred mechanically. Sodium dichromate +(Na2Cr2O7 2H2O) is now added in small quantities (PRECAUTION: see Notes), +with constant stirring, until the temperature of the mixture reaches 40'0; +the empty water bath is now filled with cold water and the addition +of sodium dichromate continued at such a rate that the temperature +remains at 45-55'0. In all 540 g. of sodium dichromate are added, +the addition taking one to two hours. When all has been added, +the mixture, which has now become very thick, is stirred for two +hours at 45-55'0, and poured into a crock containing 4 kg. +of crushed ice. The insoluble trinitrobenzoic acid is filtered off, +and carefully washed with cold water until free from chromium salts. +On drying it weighs 320-340 g. + +The product is now mixed with 2 l. of distilled water at 35'0 +in a 5-l. flask provided with a stirrer, and 15 per cent sodium +hydroxide solution is dropped in with continuous stirring until +a FAINT red color is just produced. Should this disappear, +it is restored by the addition of a few drops more. When it has +persisted for five minutes, the color is discharged by the addition +of a few drops of acetic acid, and the insoluble unattacked +trinitrotoluene filtered off and washed with a little water. +The trinitrobenzoic acid is precipitated from the filtrate +by the addition of a slight excess of 50 per cent sulfuric acid. +The solution is chilled, and the acid filtered and washed free +from salts with ice water. When dried in air it weighs 230-280 g. +(57 to 69 per cent of the theoretical amount). + +2. Notes + +The mother liquors and washings lose carbon dioxide on boiling, +and the insoluble trinitrobenzene separates see preparation XXIV); +after filtering, washing, and drying, it weighs 15-20 g. +(4 to 6 per cent of the theoretical amount). + +It is essential that the stirring should be most efficient, +so that when the mixture becomes thick the dichromate will be evenly +distributed throughout the liquid, as rapidly as it is added. +If the stirring is not efficient, local reactions of extreme violence +(in certain cases leading to conflagration) will occur. +An iron stirrer may be employed in the oxidation reaction, +but not in the purification. + +Technical sodium dichromate generally contains a certain amount +of chlorides, and the chlorine liberated from these tends +to cause a troublesome foam towards the end, of the reaction. +Only a very efficient stirrer, which draws down the surface of the liquid, +is able to combat this difficulty. The amount of solid sodium +dichromate given is for the dry crystalline compound containing +two molecules of water of crystallization. + +Great care should be taken in dissolving the crude acid in the alkali. +If an excess of alkali persists for any length of time, a permanent +color is produced which will discolor the final product. +The acid is fairly soluble in cold water and should be washed with care. + + +3. Other Methods of Preparation + +2,4,6-Trinitrobenzoic acid has been prepared by heating trinitrotoluene +with fuming acid in a sealed tube to 100'0, for two weeks,[1a] +the oxidation being only partial. It can also be prepared by heating +trinitrotoluene under a reflux condenser, with a mixture of 5 parts +of concentrated nitric acid and 10 parts of concentrated sulfuric +acid;[1] this method is, however, unsuitable in the laboratory +owing to the difficulty of devising suitable apparatus. +Another method is to dissolve trinitrotoluene in nitric acid and, +to this solution (at 95'0), to add potassium chlorate at such a rate +that the temperature does not fall;[2] this method has been found +to be difficult to control on a laboratory scale. + + +[1a] Ber. 3, 223 (1870) + +[1] D. R. P. 77,559; Frdl. 4, 34 (1894) + +[2] D. R. P. 226,225; Frdl. 10, 167 (1910). + + +The method described above is a modification of a patented process,[3] +in which trinitrotoluene suspended in sulfuric acid is treated +with chromic anhydride. + +[3] D. R. P. 127,325; Frdl. 6, 148 (1901). + + + +INDEX + +A + +Acetic acid, 18, 33, 64 Acetone, 41 Acetophenone, 1 Ammonium carbonate, +75 Ammonium hydroxide, 37, 75 Aniline, 71, 79 Anthranilic acid, 47 + +B + +Benzalacetophenone, 1 Benzaldehyde, 1, 5 Benzoic acid, 5 Benzyl alcohol, +5 Benzyl benzoate, 6 Benzyl chloride 9 Benzyl cyanide, 9-11, 27, +57, 63 Bromostyrene, 67 + +C + +Carbon tetrachloride, 23 Chlorine, 37 Copper sulfate, 38 + +D + +Dibenzyl ether, 6 a, g-Dichloroacetone, 13-15 Dimethylaminobenzaldehyde, +17-21 Dimethylaniline, 17, 47 + +E + +Ethyl alcohol, 23, 27 Ethyl oxalate, 23-26 Ethyl phenylacetate, 27-28 + +F + +Ferrous sulfate, 79 Formaldehyde, 17 + +G + +Gelatine solution, 37 Glycerol, 29, 33, 79 Glycerol a, +g-dichlorohydrin, 29-31 Glycerol a-monochlorohydrin, 33-35 + +H + +Hydrazine sulfate, 37 40 Hydrochloric acid, 17, 30, 34, 47, +71 Hydroquinone, 85 + +M + +Mesitylene, 41-45 Methyl red, 47-61 + +N + +Naphthol, 61 Nitric acid, 57 Nitrobenzene, 79 _p_-Nitrobenzoic acid, +63-66 _p_-Nitrobenzyl cyanide, 67-58, 59 _p_-Nitrophenylacetic acid, +6940 Nitrosodimethylaniline hydrochloride, 17 Nitroso-,3-naphthol, +61-62 Nitrotoluene, 53 + +O + +Oxalic acid, 23 + +P + +Phenylacetic acid, 10, 63-65 Phenylacetylene, 67-69 Phenylhydrazine, +71-74 Phthalic anhydride, 75 Phthalimide, 7~78 Potassium hydroxide, 67 + +Q Quinoline, 79 83 Quinone, 86 88 S + +Sodium acetate, 48 Sodium benzylate, 6 Sodium cyanide, 9 Sodium dichromate, +13, 53, 85, 95 Sodium hydroxide, 1, 37, 61, 93 Sodium hypochlorite, +37 Sodium, metallic, 5, 42 + +Sodium nitrite, 17, 47, 61, 71, 80 Sodium sulfite, 71 Sodium +_p_-toluene sulfinate,--91 Sulfur dioxide, 71 Sulfuric acid, +13, 27, 30. 34, 37, 41, 43, 53, 57, 59, 63, 79, 85, 95 + +T Toluene, 48 Toluenesulfonyl chloride, 89 I, 3, s-Trinitrobenzene, 93-- +94, 96 2, 4, 6-Trinitrobenzoic acid, 93, 96 97 2, 4, 6-Trinitrotoluene, 93, +95 Zinc dust, 89 + + + + + +End of The Project Gutenberg Etext of Organic Syntheses, Conant, Editor + diff --git a/1234.zip b/1234.zip Binary files differnew file mode 100644 index 0000000..60ad3a1 --- /dev/null +++ b/1234.zip diff --git a/LICENSE.txt b/LICENSE.txt new file mode 100644 index 0000000..6312041 --- /dev/null +++ b/LICENSE.txt @@ -0,0 +1,11 @@ +This eBook, including all associated images, markup, improvements, +metadata, and any other content or labor, has been confirmed to be +in the PUBLIC DOMAIN IN THE UNITED STATES. + +Procedures for determining public domain status are described in +the "Copyright How-To" at https://www.gutenberg.org. + +No investigation has been made concerning possible copyrights in +jurisdictions other than the United States. 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