Organic Syntheses

Part 2 out of 2

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).



C6H5CH2CN + 2H2O + H2SO4--> C6H5CH2CO2H + NH4HSO4

Prepared by ROGER ADAMS and A. F. THAL. Checked by O. KAMM and

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.



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).



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.


2C<6s4< >O + (NH4)2CO3--> 2NH + 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.



/ \ / \ 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).



(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).



2CH3C6H4SO2Cl + 3Zn--> (CH3C6H4SO2)2Zn + ZnCl2 (CH3C6H4SO2)2Zn +
Na2CO3--> 2CH3C6H4SO2Na + ZnCO3


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).



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.

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).



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).



Acetic acid, 18, 33, 64 Acetone, 41 Acetophenone, 1 Ammonium carbonate,
75 Ammonium hydroxide, 37, 75 Aniline, 71, 79 Anthranilic acid, 47


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


Carbon tetrachloride, 23 Chlorine, 37 Copper sulfate, 38


Dibenzyl ether, 6 a, g-Dichloroacetone, 13-15 Dimethylaminobenzaldehyde,
17-21 Dimethylaniline, 17, 47


Ethyl alcohol, 23, 27 Ethyl oxalate, 23-26 Ethyl phenylacetate, 27-28


Ferrous sulfate, 79 Formaldehyde, 17


Gelatine solution, 37 Glycerol, 29, 33, 79 Glycerol a,
g-dichlorohydrin, 29-31 Glycerol a-monochlorohydrin, 33-35


Hydrazine sulfate, 37 40 Hydrochloric acid, 17, 30, 34, 47,
71 Hydroquinone, 85


Mesitylene, 41-45 Methyl red, 47-61


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


Oxalic acid, 23


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


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