Organic Syntheses ...............................................................................................................................................1

James Bryant Conant, Editor...................................................................................................................1

VOL. II. ...................................................................................................................................................2

INTRODUCTION TO THE SERIES ......................................................................................................2

I. BENZALACETOPHENONE..............................................................................................................3

II. BENZYL BENZOATE .......................................................................................................................4

III. BENZYL CYANIDE .........................................................................................................................6

IV. a, gDICHLOROACETONE ............................................................................................................7

V. _p_DIMETHYLAMINOBENZALDEHYDE ..................................................................................9

VI. ETHYL OXALATE........................................................................................................................11

VII. ETHYL PHENYLACETATE ........................................................................................................13

VIII. GLYCEROL a, gDICHLOROHYDRIN....................................................................................14

IX. GLYCEROL aMONOCHLOROHYDRIN ...................................................................................15

X. HYDRAZINE SULFATE .................................................................................................................17

XII. METHYL RED..............................................................................................................................19

XIII. _p_NITROBENZOIC ACID......................................................................................................21

XIV _ p_NITROBENZYL CYANIDE...............................................................................................22

XV. _p_NITROPHENYLACETIC ACID..........................................................................................23

XVI. NITROSObNAPHTHOL.........................................................................................................24

XVII. PHENYLACETIC ACID............................................................................................................26

XVIII. PHENYLACETYLENE............................................................................................................27

XIX. PHENYLHYDRAZINE...............................................................................................................29

XXII. QUINONE ...................................................................................................................................30

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 today 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

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 onehalf 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

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 onehalf 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 substituted 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

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 editorinchief 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

Prepared by E. P. KOHLER and E. M. CHADWELL. Checked by H. T. CLARKE and R. P. LEAVITT.

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 5500cc. 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

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 icebox for about ten hours.

The mixture now is a thick paste composed of small shotlike 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 5054'0. 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 lightyellow material (m. p. 5557'0) and 4050 g. that require

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 stillhead (preferably under diminished pressure) and using only the fraction which boils at 201202'0

(7677'0/10 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

If the temperature is too low, or the stirring too slow, the product separates as an oil, which later solidifies in

If the temperature is allowed to rise above 30'0, secondary reactions diminish both the yield and the purity of

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

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]

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

5060'0 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

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 boilingpoint of benzyl benzoate, when the receivers are changed. The product boils at

184185'0/15 mm., and analysis by saponification shows it to consist of 99 per cent ester. A yield of

410420 g. is obtained, which corresponds to 9093 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.

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:

Dibenzyl ether no doubt forms the chief impurity in benzyl benzoate. Since the boilingpoint 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

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

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

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.

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

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 (1095 per cent), as well as in regard to purity of the product (8797 per cent ester).[1] As a

result of the present study,[2] causes for variations are fully accounted for and the procedure has been

IN a 5l. roundbottom flask, fitted with a stopper holding a reflux condenser and separatory funnel, are

placed 500 g. of powdered sodium cyanide (9698 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. 170180'0) mixed with 1 kg. of alcohol is run in through the separatory funnel in the course of onehalf to

threequarters 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 sidearm[1] (Vol. I, p. 40, Fig. 3) which gives the same effect

as a fractionating column. The material is collected from 135140'0/38 mm. (115120'0/10 mm.). The yield

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 6075 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 highboiling 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

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 strawcolored 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 12'0

range. For most purposes, such as the preparation of phenylacetic acid or ester, the fraction boiling

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

Prepared by J. B. CONANT and O. R. QUAYLE. Checked by A. W. DOX, L. YODER, and O. KAMM.

IN a 2l. flask are placed 375 g. of commercial sodium dichromate, 225 cc. of water, and 300 g. of

dichlorohydrin (b. p. 6875'0/14 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 tenminute

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

Sufficient water is now added to the mixture to dissolve the pasty chromium salts (300800 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 1525 cc. of ice water, then with 1015 cc. of cold petroleum ether, and finally

centrifuged till as dry as possible. The crude dichloroacetone is dried in a vacuum desiccator over sulfuric

The crude product is best purified by distillation from a 250cc. distilling flask fitted with an air condenser.

A very small fraction (1015 g.) of lowboiling material is obtained, and the dichloroacetone (170175'0) is

then collected. It solidifies in the receiver to a white crystalline mass which weighs 200220 g. (6570 per

cent of the theoretical amount). A few grams more may be obtained by chilling the lowboiling fraction and

Great caution should be exercised in working with dichloroacetone, as it is extremely lachrymatory and

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, 1015 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.

It is not necessary to wash the crystals in the centrifuge until they are white. A small amount of chromic salt

Commercial sodium dichromate is hygroscopic and contains varying amounts of water. The 375 g. required

The total time required for the oxidation is twentyfour 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

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 (CH2ClCCl=CH2) and hypochlorous acid;[4] the action of

hydrochloric acid on ethoxymonochloroacetoacetic ester;[5] and the hydrolytic cleavage of

[1] Jahresb. 1859, 345; 1871, 531; J. prakt. Chem. (2)4, 52 (1871); Ber. 7, 467 (1874); 8, 1330, 1438 (1875);

[2] Ber. 6, 1210 (1873); 13, 1706 (1880); 42, 3233 (1909); Ann. 208, 355 (1881); 269, 46 (1892); Ann. chim.

Prepared by ROGER ADAMS and G. H. COLEMAN. Checked by H. T. CLARKE and W. W. HARTMAN.

IN a 3l. roundbottom 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

In a 2l. 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 5l. 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 4l. 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 1l.

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 sidearm of the distilling flask warm; otherwise, on starting the distillation

again, the aldehyde will solidify in the sidearm 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 2l. 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 125130 g. (5659 per cent of the

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 (1520 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

95100 g., m. p. 73'0. The succeeding runs yield 115128 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.

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

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 500cc. distilling flask instead

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

When the apparatus for distilling, etc., is all set up, a run such as described above requires about five to six

_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

[1] Ber. 18, 1519 (1885); 19, 366 (1886); D. R. P. 61, 551; Frdl. 3, 109 (1892).

Prepared by H. T. CLARKE and ANNE W. DAVIS. Checked by ROGER ADAMS and W. B. BURNETT.

IN a 5l. 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

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 twentyseven

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 106107/25

mm. is collected. The yield is 920960 g. of a colorless liquid (8084 per cent of the theoretical amount).

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

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

It is not absolutely necessary to remove the last traces of water from the alcoholcarbon 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

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 sidearm 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

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 4050'0.[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

IN a 3l. roundbottom 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 132138'0/32 mm. (120125'0/1718

mm.). The yield varies in general between 525 and 550 g. (8387 per cent of the theoretical amount).

The benzyl cyanide can be most conveniently prepared according to the directions in preparation III (p. 9);

In washing the layer of ethyl phenylacetate with sodium carbonate it is sometimes advisable to add a certain

The product obtained is waterclear 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

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

Prepared by J. B. CONANT and O. R. QUAYLE. Checked by O. KAMM and A. O. MATTHEWS.

ONE kilo of 90 per cent glycerol (sp. gr. 1.243) and 20 g. of acetic acid are placed in a weighed 2l. flask

which is immersed in an oil bath heated to 100110'0. The flask is fitted with a twohole 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 catchbottle 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

The product is now cooled, placed in a 4l. 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 6875'0/14 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 (4045 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

The 875 g. of dichlorohydrin thus obtained boils over a 7'0 range; this is 70 per cent of the theoretical

amount. Redistillation yields 700720 g. boiling 7073'0/14 mm. (57 per cent of the theoretical amount).

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 3l. bottle for

this container and a 1l. funnel to contain the hydrochloric acid. The gas is dried by passing through a

washbottle containing concentrated sulfuric acid. An empty catchflask 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.

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 12 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 12 per cent of acetic acid as a catalyst by gaseous hydrogen chloride. Therefore this

[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.

[5] Ann. 122, 73 (1862); 168, 43 (1873); Ber. 5, 354 (1872); Ann. chim. phys. (6) 22, 437 (1891).

Prepared by J. B. CONANT and O. R. QUAYLE. Checked by O. KAMM and A. O. MATTHEWS.

FIVE HUNDRED grams of glycerol (90 per cent) and 10 g. of glacial acetic acid are mixed in a weighed 1l.

flask, which is placed in an oil bath heated to 105110'0. 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., 220250 g. distil; this portion is

mostly water. The monochlorohydrin is collected between 114120'0/14 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

The same apparatus is employed as in the preparation of dichlorohydrin (preparation VIII, p. 29).

The portion boiling 120130'0/14 mm. only amounts to 1530 g., showing that very little of the bcompound

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

An alternative procedure which is slower and gives slightly lower yields, but does not require a hydrogen

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 2l. 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) 115117'0/ 11 mm.; (3)

117170'0/11 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 115118'0/11 mm. or 133136'0/20 mm. is

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 (12 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

[1] Ann. 88, 311 (1853); Ann. chim. phys. (3) 41, 297 (1834); V. R. P. 254,709; 269,657; Frdl. 11, 31 (1912).

Prepared by ROGER ADAMS and B. K. BROWN. Checked by J. B. CONANT and W. L. HANAWAY.

A NORMAL solution of sodium hypochlorite is prepared as follows: in a 5l. roundbottom 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 14inch 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 onethird 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 aterial has been employed by Clarke and

Hartman, and yields a slightly highergrade 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 6070 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 163167'0 is

The cooling of the reaction flask must be very efficient, a 1015 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

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

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 highboiling product which tends to cause emulsification of the alkali in the

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

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 diacetomesitylene;[7] the treatment of methylene3dimethyl1, 5cyclohexene1 with bromine

[1] Ann. 141, 131 (1867); 147, 43 (1868); 278, 210 (1893); Bud. soc. chim. (2) 40, 267 (1883); J. prakt.

Prepared by H. T. CLARKE and W. R. KIRNER. Checked by ROGER ADAMS and J. B. DAVIS.

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 10l. 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 2025'0 in the course of twentyfour 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 fortyeight hours or longer at room

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 12l. 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

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 25cm. glass funnel which passes through the cork of a 2l. flatbottom

conical flask containing 1250 cc. of toluene (Fig. 2). The flask is heated on an electric stove, and a 12l.

roundbottom 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 90100'0; 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 755805 g. The mother

liquors are concentrated to onefourth 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

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

The amount of hydrochloric acid indicated must not be reduced; otherwise, diazoamino compounds are

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

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

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 twentyfour 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

The alcoholic filtrate, obtained on digesting and washing the crude methyl red, contains a more soluble red

byproduct which gives a brownishyellow 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 byproduct. The proportion of this byproduct 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

When the methyl red is crystallized from toluene, it sometimes separates in the form of brightred lumps,

probably on account of too rapid crystallization. Under these conditions it is advisable to crystallize again,

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 (650700 g.). The yield of methyl red is about 65 to 70 per cent based on the

dimethylaniline actually used up, but only 5863 per cent based on the anthranilic acid actually present in the

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

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

Prepared by O. KAMM and A. O. MATTHEWS. Checked by H. T. CLARKE and W. W. HARTMAN.

IN a 5l. roundbottom 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

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 lightlemon color. The yield should be 230240 g. (8085 per cent of the theoretical

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

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

Ten or 20 g. of unchanged nitrotoluene can be recovered from the reaction mixture by steam distillation, but

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

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

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

_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

IN a 2l. roundbottom 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. (5054 per cent) of a product which melts at

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

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

The reaction has been also carried out with 500 g. of benzyl cyanide. Under these conditions a 5l. 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.

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).

IN a 1l. roundbottom 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 twothirds 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 10cm.

hole in a large sheet of asbestos board which rests on a tripod, and heated until the mixture boils. The boiling

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, paleyellow needles,

which melt at 151152'0. The yield is 103 to 106 g. (92 3 per cent of the theoretical amount).

If the flask is not protected with an asbestos board or the equivalent, decomposition occurs where the

substance is superheated 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

If a good grade of cyanide be used, it is not necessary to add boneblack in order to obtain the acid in a pure

In making experiments with 500 g. of _p_nitrobenzyl cyanide, it was found that the time for hydrolysis was

_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]

Prepared by C. S. MARVEL and P. K. PORTER. Checked by H. T. CLARKE and W. W. HARTMAN.

IN a 12l. roundbottom flask fitted with a mechanical stirrer are placed 500 g. of technical bnaphthol

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 iceandsalt 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 nitrosobnaphthol, 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 airdried 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

This product is satisfactory for all purposes. It may be obtained in a crystalline condition, however, by

recrystallizing from hot ligroin (sp. gr. 0.710.72). About 2 g. of nitrosobnaphthol will dissolve in 15 cc.

of boiling ligroin. The product is not very soluble in cold ligroin, so that nearly all is recovered.

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

A large vessel is needed for the reaction, as the nitrosobnaphthol separates in a finely divided condition

The final airdried 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 nitrosobnaphthol melted at 101105.

bnaphthoquinonechlorimide;[1] by the action of sulfuric acid upon a solution of potassium or sodium

nitrite and the sodium salt of bnaphthol;[2] by the action of sodium nitrite upon an alcoholic solution of zinc

chloride and bnaphthol;[3] by the action of sodium nitrite upon bnaphthol suspended in zinc sulfate

solution;[4] by the action of nitrous acid on bdinaphthol methane;[5] and by the action of nitrosyl sulfate

IN a 5l. roundbottom 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 2l. 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 176189'0/50 mm. is collected separately

and solidifies on standing. It is practically pure phenylacetic acid, m. p. 7676.5'0; 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

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

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 fortyfive minutes under a

reflux condenser, the hydrolysis is practically complete. The reaction mixture is then poured into water, and

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

IN a 500cc. Pyrex distilling flask are placed 150 g. of potassium hydroxide. The mouth of the flask is

provided with a onehole stopper holding a dropping funnel; the side tube of the flask is connected with a

condenser set for downward distillation. The bbromostyrene (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 142143'0, and that of bromostyrene is

While the bromostyrene is being dropped in, the temperature of the oil bath is raised very gradually to

215220'0, 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 142144'0, is 37 g. (67 per

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

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 byproducts 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

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.

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 bbromo or chloro styrene with sodium ethylate or potassium

hydroxide in alcohol;[5] by passing the vapors of adichloroethylbenzene over hot soda lime;[6] by the

action of alcoholic potassium hydroxide on dibenzalacetone tetrabromide;[1b] by the action of aqueous

potassium hydroxide on phenyl propargylaldehyde;[2b] by the action of molten potassium hydroxide on

[4] Ann. 154, 155 (1870); 235, 13 (1886); Bull. soc. chim. 35, 55 (1881); (3) 25, 309 (1901).

[6] Jahresb. 1876, 308; Gazz. chim. ital. 22 (2), 67 (1892); Bull. soc. chim. (3) 25, 309 (1901).

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

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.

Quinoline has been produced by passing the vapor of allylaniline over redhot 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]

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,

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

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

(1)HOC6H4OH(4) + O(Na2Cr2O7 + H2SO4)> O=C6H4=O + H2O Prepared by E. B. VLIET. Checked

IN a 2.5l. 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 greenishblack 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 onehalf to

threequarters 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 1l. 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 steambath, 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 1l. 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

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. (7681 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

As the mixture becomes thick during the oxidation, it is very necessary to use a stirrer which will keep the

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

When technical sodium dichromate is used, the solution should be filtered with suction, before it is added to

In the laboratory it is convenient to make several small runs of the size indicated, as far as the oxidation is

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 3l. 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

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 quinicacid,[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 enzyl alcohol, 5 Benzyl benzoate, 6 Benzyl chloride 9 Benzyl

Dibenzyl ether, 6 a, gDichloroacetone, 1315 Dimethylaminobenzaldehyde, 1721 Dimethylaniline, 17, 47

Gelatine solution, 37 Glycerol, 29, 33, 79 Glycerol a, gdichlorohydrin, 2931 Glycerol

Naphthol, 61 Nitric acid, 57 Nitrobenzene, 79 _p_Nitrobenzoic acid, 6366 _p_Nitrobenzyl cyanide,

6758, 59 _p_Nitrophenylacetic acid, 6940 Nitrosodimethylaniline hydrochloride, 17 Nitroso,3naphthol,

Phenylacetic acid, 10, 6365 Phenylacetylene, 6769 Phenylhydrazine, 7174 Phthalic anhydride, 75

Sodium acetate, 48 Sodium benzylate, 6 Sodium cyanide, 9 Sodium dichromate, 13, 53, 85, 95 Sodium

Sodium nitrite, 17, 47, 61, 71, 80 Sodium sulfite, 71 Sodium _p_toluene sulfinate,91 Sulfur dioxide, 71

T Toluene, 48 Toluenesulfonyl chloride, 89 I, 3, sTrinitrobenzene, 93 94, 96 2, 4, 6Trinitrobenzoic acid,