Manufacture of Para-diamidodiphenylaminesulphocarboxylic Acid.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Manufacture of Para-diamidodiphenylaminesulphocarboxylic Acid.
I, OLIVER IMRAY, of Birkbeck Bank Chambers, Southampton Buildings, in
the County of London, Chartered Patent Agent, do hereby declare the nature of this
invention (as communicated to me from abroad by The Farbwerke vormals: Meister
Lucius and Brüning, of Hoechst a/Main, in the Empire of Germany, Chemical
Manufacturers,) to be as follows:―
A sulphocarboxylic acid of para-diamido-diphenylamine is not yet known.
My foreign correspondents have found that this acid may be obtained by con-
densing chlornitrobenzoic acid with phenylenediaminesulphonic acid and subsequent
reduction; this acid has proved to be an important primary material for producing
substantive cotton dyestuffs.
The constitution of this new acid cannot be stated with certainty, as on condensa-
tion, a body may result having the subjoined formula I or the formula II. Formula
I seems to be the more likely

page_text: heated for from 5 to 6 hours in a vessel provided with an inverted condenser. The
solution becomes orange-brown. On completion of the condensation the liquid is
acidified with an excess of hydrochloric acid, when the free nitro-amidodiphenyl-
aminesulphocarboxylic acid is separated as a thick, light yellow brown precipitate;
it is pressed and reduced in the usual manner.
The alkali salts of para-diamidodiphenylaminesulphocarboxylic acid are easily
soluble in water. On addition of acetic acid to their aqueous solution of free acid
crystalizes out in form of needles of a pale grey-green colour.
They dissolve easily when heated in dilute mineral acid, such as, hydrochloric acid.
On cooling, this solution solidifies to a gelatinous mass, which after some time turns
into a grey crystalline precipitate, consisting of the hydrochloride of the new
compound.
+
The free acid precipitated by acetic acid is insoluble in cold water and soluble with
difficulty in hot water. The para-diam idodiphenylaminesulphocarboxylic acid is
soluble with great difficulty in concentrated alcohol. The para-diamidodiphenylamine-
sulphocarboxylic acid forms a yellow coloured tetrazo-compound soluble in water,
which can be combined with the usual components to form valuable dyestuffs. When
soda is added to the yellow solution of the tetrazo-compound, the liquid becomes
intensely red.
Dated this 20th day of March 1000
ABEL & IMRAY,
Agents for the Applicant..
COMPLETE SPECIFICATION.
Manufacture of Para-diamidodiphenylaminesulphocarboxylic Acid.
I, OLIVER IMRAY, of Birkbeck Bank Chambers, Southampton Buildings, in the
County of London, Chartered Patent Agent, do hereby declare the nature of this
invention (as communicated to me from abroad by The Farbwerke vormals Meister
Lucius and Brüning of Hoechst a/Main, in the Empire. of Germany, Chemical
Manufacturers,) and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
A sulphocarboxylic acid of para-diamido-diphenylamine is not yet known.
My foreign correspondents have found that this acid may be obtained by con-
densing para-nitro-chloro-ortho-benzoic acid

page_text: The constitution of this new acid cannot be stated with certainty, as on condensa.
tion, a body. may result having the subjoined formula I or the formula II.
I seems to be the more likely.
Formula
A solution of 20.2 kilos. of chloronitrobenzoic acid (COOH: Cl: NO, = 1:2:5)
18.8 kilos. of para-phenylenediaminesulphonic acid, 17 kilos. of soda ash and 200 litres
of water are heated for from 5 to 6 hours in a vessel provided with an inverted con-
denser. The solution becomes orange-brown. On completion of the condensation
the liquid is acidified with an excess of hydrochloric acid, when the free nitro-amido-
diphenylaminesulphocarboxylic acid is separated as a thick, light yellow brown pre-
cipitate; it is pressed and reduced by introducing the pressed cakes into a boiling
mixture of 250 litres of water, 50 kilos. of iron and 5 kilos. of glacial acetic acid,
and boiling the mixture for about half an hour, with continued stirring, after which
the mixture is made alkaline with sodium carbonate and filtered from the separated
iron oxide.
The alkali salts of para-diamidodiphenylaminesulphocarboxylic acid are easily
soluble in water. On addition of acetic acid to their aqueous solution the free acid
crystallises in form of needles of a pale grey green colour.
They dissolve easily when heated in dilute mineral acid, such as, hydrochloric
acid. On cooling, this solution solidifies to a gelatinous mass, which after some time
turns into a grey crystalline precipitate, consisting of the hydrochloride of the new
compound.
The free acid precipitated by acetic acid is insoluble in cold water and soluble
with difficulty in hot water.
The para-diamidodiphenylaminesulphocarboxylic acid is soluble with great difficulty
in concentrated alcohol. The para-diamidodiphenylaminesulphocarboxylic acid
forms a yellow coloured tetrazo-compound soluble in water, which can be combined
with the usual components to form valuable dyestuffs. When soda is added to the
yellow solution of the tetrazo-compound, the liquid becomes intensely red.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be perforined, I declare that what I
claim is :-
The herein described manufacture of para-diamidodiphenylaminesulphocarboxylic

page_text: =
1:25) with
acid by condensing para-nitro-chlorbenzoic acid (COOH: Cl: NO₂
para-phenylenediaminesulphonic acid and by reducing the nitro-product thus
obtained.
2
The oid manufactured as above out fouth