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scopic scales. Nearly insoluble in water and in alcohol.



24 C


Dried at 100.
144 ....


51'06 .,


Zinin.
50-64


2 N


. 28


9-93




14 H


. 14 ....


4-97




2 O .


16 ....


5-67 M


5-10


2 SO 3 .


80 ....


28-37 .


28-47











C 24 N 2 H 12 ,2HO,2SO 3 282 .... 100-00

b. Hyperacid. The yellowish solution of benzidine in cold or
slightly heated oil of vitriol, remains liquid even in the cold, but on a
slight addition of water, crystallises at ordinary temperatures in a
radiated mass, and on a larger addition of water, solidifies in a pulp
consisting of tho pulverulent salt a.

HydrocMorate of Benzidine. Crystallises from water or alcohol in
white, nacreous, rhombic laminae, which are not altered by exposure to
the air, or by a temperature of 100; but, if exposed to the air in contact
with ether or acids, acquire a dirty green colour, and lose their crys-
talline form.

Zinin.

24 C 144-0 .... 56-08 56-12

2 N 28-0 .... 10-90

14 H 14-0 .... 5-45 5-64

2 Cl 70-8 .... 27-57 27'28

C 24 N 2 H 12 ,2HC1 .... 256-8 .... 100-00

Nitrate of Benzidine. The solution of benzidine in warm dilute
nitric acid, yields on cooling thin right-angled laminae, permanent in
the air.

Benzidine forms with protochloride of mercury a double salt having
the form of white shining laminae easily soluble in water and alcohol.

Chloroplatinate of Benzidine. The yellow crystalline precipitate
which an aqueous or alcoholic solution of hydrochlorate of benzidine
forms with bichloride of platinum. This precipitate when heated with
water is decomposed at the boiling heat, but not below; it is also decom-
posed by alcohol, especially when hot, and still more quickly by ether,
and converted into a dark violet powder. It dissolves sparingly in
water, and scarcely at all in alcohol or ether.

Dried in vacuo over oil of vitriol. Zinin. Noble.

24 C ... .. 144-0 , 24-15



2 N 28-0

14 H 14-0

2 Pt 198-0

6 CL... ... 212-4



4-69
2-35
33-19 .... 33-03 .... 33-09

35-62



2PtCl 2 ... 596-4 .... 100-00

Acetate of Benzidine. White, shining, thin, elongated laminae, easily
soluble in water and alcohol.



gr
dil



AZOXYBENZENE. 341

Oxalate of Benzidine. Delicate silky needles united in stellate
roups, permanent in the air, not changing at 100, dissolving with soino
'fficulty in water and alcohol.



28 C


Crystals.
168


6T31


Zinin.
6T46


2 N .


28


10-22




14 H . .


14


5-11


5-39


8 O


64


23'36













C 24 N 2 H 12 ,C 4 H 2 O 8 274 .... 100-00

Tartrate of Benzidine. White shining laminaB resembling benzidine,
but more easily soluble in water.

Benzidine dissolves readily in alcohol, and still more readily in ether.
(Zinin.)



Azoxybenzene.
C 2 *N 2 H 10 2 = C^N 2 !! 10 ,*) 2 .

ZININ. (1845.) J. pr. Chem. 36, 98.

LAURENT & GERHARDT. Compt, chim. 1849, 417; also Ann. Pharm.
75, 70.

Azoxylenzid, Azoxydifune.

Preparation. 1 pt. of pulverized hydrate of potash is added to a
solution of 1 pt. of nitrobenzene in a tenfold volume of alcohol, the
liquid boiled as soon as the heat spontaneously developed has subsided;
the brown needles of azoxybenzene which already separate on cooling,
collected; the remaining liquid distilled till it separates into two layers,
(p 202 ), and the upper brown oily layer decanted and washed with
water; it then solidifies after a few hours in a mass of needles of impure
azoxybenzene. These crystals, together with the needles previously
obtained, are strongly pressed between paper, and purified by several
crystallisations from alcohol and ether. The purification may be acce-
lerated by passing chlorine through the brown solution in hot alcohol till
it turns yellow. (Ziniu.)

Properties. Yellow, shining, four-sided needles, and (by spontaneous
evaporation of the ethereal solution) prisms an inch long, as hard as sugar,
and easily friable. Melts at 36 into a yellow, strongly refracting liquid,
which, at a temperature immediately below 36, solidifies in a radiated
mass.

Crystals dried over oil of vitriol. Zinin.

24 C 144 .... 72-72 72-65

2 N 28 .... 14-15 13-99

10 H 10 .... 5-05 5-28

2 O 16 .... 8 08 8-08

C 2t N 2 H 10 2 . .. 198 , .. 100-00 100-00



342 BENZENE : CONJUGATED COMPOUNDS TWO AT. C 12 NH 5 .

Decompositions. 1. Azoxybenzene heated to the boiling point assumes
a greenish-brown colour, leaves a tumefied carbonaceous mass, and gives
off yellow vapours, which condense into a liquid mixture of impure
aniline and azoxybenzene. The first portions of the distillate are com-
paratively rich in aniline, and remain liquid on cooling, while the middle
portions are buttery, and the last portions, which contain a gradually
increasing proportion of azoxybenzene, solidify on cooling. 2. By
bromine it is converted into bromazoxybenzeue. (Laurent & Gerhardt.)
Chlorine does not exert any decomposing action on azoxybenzene, either in the fused
state or dissolved in alcohol. 3. Ordinary nitric acid acts but slightly on
azoxybenzene, even at the boiling heat; but the yellowish-red solution in
cold fuming nitric acid becomes spontaneously heated, gives off red
vapours, and then solidifies on cooling in a mass of soft yellow needles
(consisting, according to Laurent & Gerhardt, of nitrazoxybenzene
C 24 N 2 XH 9 2 ). (Zinin.) 4. Its yellowish-red solution in slightly heated
oil of vitriol, deposits, on addition of water, a small quantity of greenish
oil, which soon solidifies as azoxybenzene mixed with a greenish resin,
whilst the water appears to retain a conjugated sulphuric acid. (Zinin.)
5. Hydrosulphate of ammonia converts it into benzidine. (Laurent <fc
Gerhardt, Compt. Chem. 1849, 166.) [Probably thus: C 24 N 2 H 10 O 2 + 4HS =



Combinations. It does not dissolve in water, aqueous sulphuric acid,
ammonia or potash.

It dissolves readily in alcohol and still more readily in ether. From
its solution in alcoholic hydrochloric acid, it is precipitated in its original
state by alcoholic ammonia or potash. (Zinin.)



Bromazoxybenzene.

3 _ C 2 *N 2 BrH 9 ,0.



LAURENT & GERHARDT. Compt. chim. 1849, 417; also Ann. Pharm.
75, 72.

Gebromtes Azoxybenzid, Azoxybenzide 6rome, Bromazoxydifune.

Azoxybenzene is converted by bromine into a yellowish, easily fusible
substance which solidifies in crystalline nodules on cooling, and dissolves
very sparingly in alcohol. (Laurent & Gerhardt.)



24 C


144


51-98


Laurent & Gerhardt.
46-7


2 N


28


10-11




Br


. . . 80


28-88


31-9


9 H


9


3-25


2'7


2 O


16


5*78













C 24 N 2 BrIi 9 O 2 277 .... 100*00

The substance analysed was doubtless contaminated with a Uglier bronrine-eomi
pound. (Laurent & GerLardt.)



NITRAZOXYBENZENE. 343



Nitrazobenzene.
C M N 8 H 9 0* = C 2i N 2 XH 9 .

ZININ. (1845.) J. pr. Chem. 36, 103.

LAURENT & GERHARDT. Compt. chim. 1849, 417; also Ann. Pharm.
75, 73.

Nitrazo 6 enzid, Nitrazo difune.

Preparation. 1. The crystalline magma produced by the action of
faming nitric acid on azobenzene is drained in a filter plugged with
asbestus, and afterwards on a brick to free it from the mother-liquor; the
residue dissolved in strong boiling alcohol; and the yellow nitrazobenzene,
which is more readily soluble in alcohol and ether, separated by repeated
crystallisation from the binitrazobenzene which crystallises much more
easily. (Zinin.) Azobenzene is gently heated with fuming nitric acid;
the liquid left to cool after the action is finished; the mother-liquor
decanted from the yellowish-red mass of needle-shaped crystals thus pro-
duced; the crystals washed with ordinary nitric acid, then with a little
water, and boiled with alcohol; the oil decanted [from the binitrazoben-
zene?]; and the needles which separate therefrom, washed with a small
quantity of alcohol and ether to remove an oily product. (Laurent &
Gerhardt.)

Properties. Slender needles of a dull straw-yellow colour. Pale
orange-yellow, somewhat laminated needles, fusing more readily than
binitrazobenzene, and crystallising as the liquid cools. (Laurent &
Gerhardt.)

Laurent & Gerhardt.



24 C


144


.... 63-44


62-5


3 N


42


18-50


18-1


9 H


9


3-96


3'9


4 O


32


. . 14-10


.. . 15-5










C 24 N 3 H 9 O 4


.. 227


.. 100-00


.. 100-0



It dissolves in alcohol less readily than azobenzene, but more readily
than binitrazobenzene. (Laurent & Gerhardt.)



Nitrazoxybenzene.
CPWH'O 6 = C 24 N 2 XH 9 ,O a .

ZININ. (1845.) J. pr. Chem. 36, 99.

LAURENT & GERHARDT. Compt. chim. 1849; also Ann. Pharm.
75, 71.

Nitrazoxybenzid, Nitrazwydifune,



344 BENZENE : CONJUGATED COMPOUNDS OF TWO AT. C 12 NH 5 .

Preparation. The needles formed after the cooling of a solution of
azobenzene in fuming nitric acid (p. 338), are drained on asbestus, dried
on a brick, and crystallised from hot alcohol. The alcoholic mother-
liquor yields by evaporation, yet another body, in four-sided prisms, which
dissolve very easily in alcohol and ether, and without decomposition in
fuming nitric acid at the boiling heat. (Zinin.) Laurent and Gerhardt
heat the nitric acid solution to the boiling point.

Properties. Dull yellow needles united in tufts. (Laurent Ger-
hardt.)

Laurent & Gerhardt.



24 C


144


59-26


58*8


3 N .


42


17-29


Ifj. 5


9 H


9


3-70


3'6


6 O


48


. 19-75


21*1











C 24 N 3 H 9 O G 243 .... 100-00 100-0

The red-brown solution of the yellow needles in alcoholic potash depo-
sits, when evaporated with water, an aurora-red, crystalline powder, which
decomposes when heated, and is nearly insoluble in alcohol and ether; it
contains 70'1 p. c. C, 17*5 N, 4/5 H, and 7*9 0, and is therefore per-
haps C 48 N 5 H 19 4 or C 24 N 3 H 9 2 . (Laurent & Gerhardt.)

The needles dissolve in fuming nitric acid at the boiling heat, and
crystallise undecomposed on cooling. (Zinin.)

They dissolve sparingly in alcohol (and in ether, according to Laurent
& Gerhardt), and crystallise on cooling. (Zinin.)



Binitrazobenzene.

C 24 N 4 H 8 8 = C 24 N 2 X 2 8 .

ZININ. (1845.) J. pr. Chem. 36, 103.

LAURENT & GERHARDT. Compt. chim. 1849, 417; also Ann. Pharm.
75, 74.

Binitrazo&enzid, Binitrazodifune.

^Preparation. 1. According to Zinin (p. 343). 2. Azobenzene is
boiled for some minutes with fuming nitric acid; the mother-liquor, when
cold, decanted from the red needles; and these needles washed with ordinary
nitric acid, then with water, then with ether, and crystallised from boiling
alcohol. (Laurent & Gerhardt.)

Properties. Small rhombic tables, having an aurora-red colour and
almost metallic, lustre (Zinin); aurora-red needles, less fusible than nitrazo-
benzene, and forming a blood-red liquid which crystallises in needles
(Laurent & Gerhardt.)






BINITRODIPHENAMIC ACID. 345



24 C


144 ....


Laurent & Gerhardt.
52-94 52-4
20-59
2-94 2-9


4 N


56 ....


8 H


8 ....


8 O


64 . ..


23-53









C 24 N 4 H s O 3 272 .... 100-00

Boiled with hydrosulphate of ammonia and with alcohol, it is con-
verted into diphenine. (Laurent & Gerhardt.)

C 12 N^H 8 O 8 + 12HS = 2C 12 N 6 H 6 + 8HO + 12S.

It dissolves without decomposition in boiling nitric acid, and sepa-
rates therefrom in finer crystals than from alcohol. (Laurent &
Gerhardt.)

It is nearly insoluble in cold, and very sparingly soluble in boiling
alcohol and ether. (Zinin.)



Binitrodiphenamic Acid,
= c*x a A<PH 8 ,0 4 .



LAURENT & GERHARDT. (1849.) Compt. chim. 1840; abslr. Ann.
Pharm. 75, 68.

Binitrodifunamsaure, Binitrodiphanaminsaure, Acide binitrodiphenamique.

The black-brown mass of needle-shaped crystals obtained by gently
heating binitrocarbolic acid with hydrosulphate of ammonia (p. 206), is
boiled with excess of acetic acid, the liquid filtered hot to separate
sulphur, and the acid left to crystallise from the filtrate.

Black-brown, thick, six-sided needles with four lateral edges of 131 30'
and two of 97; they yield a brown powder and give off their 4 atoms
of water of crystallisation between 100 and 150.

Crystals with 4 Aq. Laurent & Gerhardt.



24 C


144


.... 41-88 .


42-0


4 N


56


.... 16-28 .


16-5


16 H


. 16


4-65


4-6


16 O


128


. . 37'21 .


36-9











4Aq 344 .... 10 o-00 100-00

The crystals when heated, first give off their water, then melt,
yielding a sublimate of a few laminae and a small quantity of a brown
oily distillate, and leave a large quantity of charcoal which takes fire at
a somewhat higher temperature.

The deep red solution of the acid in aqueous ammonia gives off the
ammonia when evaporated, and leaves the pure acid.

The brown-red solution of the acid in aqueous potash yields the
potash-salt by spontaneous evaporation, in deep red crystalline nodules



346 BENZENE : CONJUGATED COMPOUNDS OF TWO AT. C 12 NH 5 .

which dissolve very readily in water and alcohol, and, when dried at
100, contain 107 per cent, of potash, and are therefore C 24 N 4 H 11 K0 12 .

The ammoniacal solution of the acid forms with acetate of baryta,
red-brown, sparingly soluble needles ; with lime-salts, after a while,
small needles; with acetate of lead, a yellowish red-brown precipitate ;
with cupric acetate, a yellowish-green precipitate; and with nitrate of
silver, a deep yellowish-brown precipitate, which, when warm solutions are
used, crystallises in laminae. (Laurent & Gerhardt.)



Silver-salt.
24 C . 14d


Laurent & Gerhardt.
34-70 24-7


4 N


56


13-19
2-66


2-6


11 H ...


11


Ag ...


108 ....


26-02


26-4


12 O


96


23-13









.. 100-00



IT. Nitrosulphobenzene.

8 _ C 24 XH 9 (S0 2 ) 2 .



H. GERICKE. Ann. Pharm. 100, 208.

When sulphobenzene (p. 165) is heated with fuming nitric acid, and
the resulting liquid mixed with water, a precipitate is formed consisting
of nitrosulphobenzene and binitrosulphobenzene, the former of which may
be extracted by hot alcohol, while the greater part of the latter remains
uiidissolved; and the alcoholic solution, on cooling, deposits the nitrosul-
phobenzene in the form of a honey-yellow, unctuous, plastic mass, which
gradually solidifies. From a solution in dilute alcohol, it separates by
spontaneous evaporation in soft microscopic crystals having their faces
lenticularly rounded. The solution frequently also deposits crystals of sulpho-
benzene.

Nitrosulphobenzene melts between 90 and 95, and is completely
decomposed at 250. Sulphide of ammonium converts it into amidosul-
phobenzene.



24 C


. .. . 144


54*7


Gericke.
55-5


N ..


14


5-3




9 H


9


3'4


. .. . 4-0


2 S


32


.... 12-2


12-7


8 O


64


24-4













C 24 NH 9 S 2 8 263 .... 100-0

= C 12 XH 4 SO 2 ,C 12 H 5 SO 2 . (Gericke.)



Insoluble in cold water, and dissolves but sparingly in hot water,
whence it separates in oily drops on cooling. Dissolves in nitric acid,
but not in sulphuric or hydrochloric acid. Caustic alkalis, with the aid



AMIDOSULPHOBENZENE. 347

of heat, dissolve it in small quantity; so likewise do alkaline carbonates,
and without evolution of carbonic acid. Hot alcohol dissolves it readily.
(Gericke.)



If. Binitrosulphobenzene.

C 24 JN T2 H 8 S 2 12 = C^X'H^SO 2 ) 2 .

GERICKE. Ann. Pharm. 100, 211.

Formed, together with the preceding compound, by the action of
fuming nitric acid on sulphobenzeue, or more abundantly by the action of
a mixture of fuming nitric acid and oil of vitriol on the same compound.
It is purified from the mononitrated compound by means of hot alcohol,
in which it is but sparingly soluble.

Small white rhombic tables having a silky lustre. Melts at 164, and
solidifies in a crystalline mass on cooling. Sublimes without decomposi-
tion at 320.



24 C


144


46-7


Gericke.
46-6


2 N


28


9-1




8 H


8


2-6


3'0


2 S


32


10-4


. .. 10-5


12 O


96


31-2













C 24 N 2 H 8 S 2 O 12 308 .... 100-0

This formula being completely divisible by 2, it might appear as if the com-
pound should rather be regarded as nitrosulphobenzene, C 12 XH 4 SO 2 : but the double
formula is justified, or rather necessitated, by the composition of the preceding compound,
and also by that of the platinum-salt of the derived compound biamidosulphobenzene
(p. 348), the formula of which does not admit of being halved.

Binitrosulphobenzene, heated on platinum-foil, burns with a sooty
flame. It is not altered by caustic alkalis or alkaline carbonates, or by a
mixture of hydrochloric acid and chlorate of potash. Sulphide of ammo-
nium converts it into biamidosulphobenzene.

It is insoluble in water, soluble in strong nitric acid, but not in dilute
acids. It dissolves but sparingly in alcohol and ether, even when heated.
(Gericke.)



If. Amidosulphobenzene.

C 24 NH n S 2 4 = C 24 AdH 9 (S0 2 ).

H. GERICKE. Ann. Pharm. 98, 389; 100, 210.

Formed by the action of sulphide of ammonium on nitrosulphobenzeno
(p. 346). The alcoholic solution of that compound mixed with sulphide



348 BENZENE : CONJUGATED COMPOUNDS OF TWO AT. C 12 NH 5 ,

of ammonium assumes a blood-red colour, deposits sulphur, and is converted
into amidosulphobenzene. On acidulating the liquid with hydrochloric
acid, filtering and saturating with potash, the amidosulphobenzene is
obtained in the form of a yellowish-white precipitate, which may be
purified by repeated solution in hydrochloric acid and precipitating with
potash.

Microscopic four-sided prisms, which decompose partially and acquire
a darker colour when dried between paper. Heated on platinum foil, the
compound melts and then burns away with a tranquil but very sooty
flame. Dissolves sparingly in cold, readily in hot water, and in
Forms salts with acids.



Hydroclilorate. Forms reddish, well-developed, four-sided prisms.
Melts at about 90, and solidifies in a gummy mass on cooling. Dissolves
easily in water and alcohol, forming red solutions; the aqueous solution
however is partially decomposed by heating, and if then treated with
potash, gives off ammonia, and deposits a black flocculent body.



24 C


]44'0 .


Gericke.
. 53-5 53-0
. 5-2
. 4-4 4-6
. 13'3 13-3
. 11-8
.. 11-8


N .


14-0


12 H


12-0 .


Cl


35-4 .


2 S


32-0 .
32-0 .


40



269-4



100-0



Chloruplatinate. C 24 AdH 9 (S0 2 ) 2 HCl,PtCl 2 . Bichloride of platinum
added to the solution of the hydrochlorate just described, forms a yel-
lowish-brown precipitate, which does not appear crystalline under the
microscope. It fuses readily when heated on platinum-foil. Insoluble
in cold water, but dissolves with partial decomposition in hot water; cold
alcohol dissolves it readily. Contains 24'9 p. c. platinum. (Gericke.)



T Biamidosulphobenzene.
C 24 N 2 H 12 S 2 4 = C 24 Ad 2 H 8 (S0 2 ) 3 .



GERICKE. Ann. Pharm. 100, 212.

Formed by the action of sulphide of ammonium on binitrosulphoben-
zene, C 24 X 2 H 12 (S0 3 ). Precipitated by potash from the hydrochloric acid
solution, as a yellowish-white mass, which soon acquires a darker colour.
Crystallises in small, four- sided prisms, which easily melt into a brownish
mass. Dissolves sparingly in cold, readily in hot water and alcohol.
Insoluble in alkalis, Forms salts with acids.

The Hydrochlorate crystallises in rhombic prisms of a reddish colour
and longitudinally striated. Is not decomposed at 100. Dissolves
readily in water and alcohol.



CARBANILIDE. 349



24 C . .


. .. 144-0


44'9


Gericke.
45'1


2 N .. . .


28-0


87




14 H


14-0


4-4


4*9


2 Cl


70-8


22-0


. 21-5


2 S


. 32-0


lO'O




4 O .. .


32-0


10-0













C 24 N 2 H i2S 2 O 4 ,2HCl.. 320-8 .... 100-0

Cliloroplatinate. C 24 (Ad) 2 H 8 (S0 2 ) 2 , 2HC1, PtCl 2 . Brown-red, indis-
tinctly crystalline precipitate, which is affected by heat and by solvents
in the same manner as the platinum-salt of amidosulphobenzene. Con-
tains 19 4 9 p. c. of platinum.

Amidosulphobenzene and biamidosulphobenzene treated with iodide of ethyl at
100, yield merely red-brown, unctuous, uncrystallisable bodies, which do not form any
very definite products with acids or when treated with oxide of silver. (Gericke.) fl.



Carbanilide.

7 = C 24 CyNH 10 ,H 2 2 .
A. W. HOFMANN. Ann. Pharm. 57, 266.

Formation. 1. When aniline is mixed with anilocyanic acid (p. 302).
2. In the decomposition of anilocyanic acid by water (p. 302).
3. In the decomposition of aniline by phosgene gas. 4. In the decom-
position of sulphocarbanilide (p. 351) by caustic potash. 5. In the dry
distillation of aniline-urea (p. 304), melanoximide (p. 367), or monoxalate
of inelaniline (p. 355).

Preparation. The crystalline mass obtained bypassing phosgene gas not
containing any free chlorine through aniline, is treated with boiling water
to extract hydrochlorate of aniline, and the residue crystallised from
alcohol. 2. Vapour of cyanic acid is made to act on aniline, which
must be kept hot, and the carbanilide separated from the aniline- urea.
3. Aniline-urea is subjected to dry distillation. The needles which per-
haps separate with a reddish tint are easily decolorised by animal
charcoal.

Properties. White silky needles which melt at 205, and distil
without decomposition; they are inodorous at ordinary temperatures,
but have a suffocating odour, like that of benzoic acid, when heated.



26 C


Needles.
156


.... 73-58


Hofmann.
73-48


2 N


28


,. . 13-21


13-07


12 H


12


5-66


5-84


2 O


16


7-55


7-61










C 26 N 2 H 12 (


) 2 . ... 212


.. 100-00


.. 100-00



Metameric with the alkaline body, flavine.



350 BENZENE t CONJUGATED COMPOUNDS OP TWO AT. C 12 NH 3 .

Decompositions. 1. Carbanilide, rapidly heated in the. moist state,
yields carbonate of aniline and other products. 2. By oil of vitriol, it
is converted into carbonic and anilosulphuric acids :

C 26 N 2 H i2o-2 + 2HO + 4S0 3 = 2(C 12 NR7,2S0 3 ) + 2C0 2 .

3. When boiled with potash-ley, and more quickly when boiled with
hydrate of potash, it is resolved into aniline which volatilises, and a
residue of carbonate of potash :

C 26 N 2 H 12 O 2 + 2HO + 2KO = 2C 12 NH? + 2(KO,CO 2 ).

It dissolves very sparingly in water, but abundantly in alcohol and
ether. (Hofmann.)



Sulphocarbanilide.

C 28 ]X T2 H 12 S 2 = C 24 CyNH 10 ,H 2 S 2 .

A. W. HOFMANN. (1846.) Ann. Pharm. 57, 266; 70, 142.

LAURENT & DELBOS. N. J. Pharm. 10, 309.

LAURENT & GERHARDT. N. Ann. Chim. Phys. 22, 103; 24, 196.

Formation. 1. By the action of bisulphide of carbon upon aniline
(p. 253), 2. By the dry distillation of hydrosulphocyanate of aniline
(p. 261). (Hofmann.)

Preparation. 1. A mixture of aniline and bisulphide of carbon (in
equal parts, according to Laurent,) mixed with alcohol to accelerate the
decomposition, is introduced into a flask provided with a cooling tube to
cause the condensed vapours to flow back again, and heated for a day or
two in the sand-bath till it no longer gives off sulphuretted hydrogen.
The crystals thus produced are freed from excess of bisulphide of carbon
by boiling, and recrystallised from alcohol. 2. The liquid obtained by
distilling hydrosulphate of ammonia is redistilled at a gentle heat, where-
upon sulphide of ammonium and bisulphide of carbon pass over in two
layers, while sulphocarbanilide remains. (Hofmann.) 3. A mixture of
aniline, sulphocyanide of potassium and sulphuric acid is distilled, and
the distillate dissolved in boiling alcohol; it then, on cooling, yields sul-
phocarbanilide in colourless, nacreous, microscopic rhombic tables. (Lau-
rent & Gerhardt.)

Properties. From the mixture of aniline and bisulphide of carbon:
Crystalline scales (Hofmann); thick rhombic tables (Laurent); from
alcohol : Iridescent lamina) having a strong lustre. (Hofmann.) Melts at
140 and distils without decomposition. Has a peculiar odour, especially
when heated; in bitterness it exceeds all other known substances.
(Hofmann.)



MELANILINE. 351



26 C


156


68-42


Hofmann.
68-28


2 N


28


12-28


12*63


12 H


... . 12


5-26


5-28


2 S


32


.... 14-04


13-85











C 26 N 2 H 12 S 2 228 .... 100-00 100'04

Decompositions. 1. The solution of sulphocarbanilide in oil of vitriol,
when gently heated, rapidly gives off carbonic and sulphurous acids, and
if then mixed with water, solidifies in the form of anilosulphuric acid,
leaving a mother-liquor clouded by separation of sulphur :

C 26 N 2 H 12 S 2 + 4HO + 4SO 3 = 2(C 12 NH7,2SO 3 ) + 2CO 2 + 2HS.

The sulphuretted hydrogen thus liberated is resolved, however, with the



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