Manufacture of a New Amidonaphtholdisulpho Acid.
Year: 1893

page_text: Date of Application, 10th Feb., 1893
Complete Specification Left, 27th Oct., 1893-Accepted, 2nd Dec., 1893
PROVISIONAL SPECIFICATION.
[Communicated from abroad by THE ACTIEN GESELLSCHAFT FÜR ANILIN
FABRIKATION, of Berlin, Germany, Chemical Manufacturers.]
Manufacture of a New Amidonaphtholdisulpho Acid.
I, CHARLES DENTON ABEL of No. 28 Southampton Buildings, Chancery Lane,
in the County of London, Consulting Engineer and Chartered Patent Agent do
hereby declare the nature of this invention to be as follows:-
This invention relates to the production of a new amidonaphtholdisulpho acid.
For this purpose, the a naphthylaminedisulpho acid, mentioned in the German
Patent No. 40571 is first converted by sulphonation into a naphthylaminetrisulpho
acid, and this is transformed by melting with caustic alkalies into the new
amidonaphtholdisulpho acid.
The following is an example illustrating the manner in which this invention can
be carried into practical effect, but without limiting the process to the precise
details stated.
A mixture of one part of the sodium salt of the a naphthylaminedisulpho acid
(German Patent No. 40571) and of three parts of fuming sulphuric acid (con-
taining about 23 per cent. of anhydride) is heated upon the water bath until the
formation of the trisulpho acid is completed, as tested by finding that a sample
diluted with water and treated with nitrite, ceases to form colouring matters with
phenols &c.
The melt is then poured into water and converted into the lime salt or soda salt
in the usual manner.
The neutral and acid soda salts of the a naphthylaminetrisulpho acid thus obtained,
as well as the free acid itself, are very readily soluble in water; the alkaline
solution shewing a very splendid yellowish-green fluorescence.
The duration of the sulphonating process and the temperature at which it is to
be carried out depend on the strength of the fuming sulphuric acid and may be
varied accordingly.
In order to transform the a naphthylaminetrisulpho acid thus obtained into
amidonaphtholdisulpho acid, one part of the soda salt of the a naphthylamine-
trisulpho acid is melted with about 3 parts of caustic potash and some water, in an
open or closed vessel, at 170° to 220° C., until a sample, diluted with water and
rendered alkaline, ceases to show the characteristic fluorescence of the a naphthyl-
aminetrisulpho acid.
The melt is then dissolved in such a quantity of water and hydrochloric acid as
to form a saturated, slightly acid salt solution, from which on cooling the acid soda
salt of the new amidonaphtholdisulpho acid separates in light grey crystalline
needles.
The new acid is readily soluble in cold and hot water; it yields no diazo com-
pound when treated with nitrite; with chloride of iron it produces a dark-green
solution; combined with diazo- or tetrazo-compounds it yields dyestuffs, of which
especially the latter are of great practical value; the new acid combines with only
one molecule of a diazo-body, and differs in this respect from the isomeric
amidonaphtholdisulpho acid mentioned in the Specification No. 13443 of 1890.
According to its formation and general properties the new acid is to be regarded
as a disulpho acid of 1:8 amidonaphthol.
Dated this 10th day of February 1893.
ABEL & IMKAY,
Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
Manufacture of a New Amidonaphtholdisulpho Acid.
1, CHARLES DENTON ABEL, of No. 28 Southampton Buildings, Chancery Lane,
in the County of London, Consulting Engineer and Chartered Patent Agent, do
hereby declare the nature of this invention and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement:-
This invention relates to the production of a new amidonaphtholdisulpho acid.
For this purpose, the a naphthylaminedisulpho acid, mentioned in the German
Patent No. 40571, is first converted by sulphonation into a naphthylaminetri-
sulpho acid, and this is transformed by melting with caustic alkalies into the new
amidonaphtholdisulpho acid.
The following is an example illustrating the manner in which this invention can
be carried into practical effect, but without limiting the process to the precise
details stated.
A mixture of one part of the sodium salt of the a naphthylaminedisulpho acid
(German Patent No. 40571) and of three parts of fuming sulphuric acid (containing
about 23 per cent. of anhydride) is heated upon the water bath until the formation
of the trisulpho acid is completed, as tested by finding that a sample, diluted with
water and treated with nitrite, ceases to form colouring matters with phenoles &c.
The melt is then poured into water and converted into the lime salt or soda salt
in the usual manner.
The Deutral and acid soda salts of the a naphthylaminetrisulpho acid thus
obtained, as well as the free acid itself, are very readily soluble in water; the
alkaline solution shewing a very splendid yellowish green fluorescence.
The duration of the sulphonating process and the temperature at which it is to
be carried out depend on the strength of the fuming sulphuric acid, and may be
varied accordingly.
In order to transform the a naphthylaminetrisulpho acid thus obtained into
amidonaphtholdisulpho acid, one part of the soda salt of the a naphthylaminetri-
sulpho acid is melted with about 3 parts of caustic potash and some water, in an
open or closed vessel, at 170° to 220° C., until a sample, diluted with water
and rendered alkaline, ceases to show the characteristic fluorescence of the
naphthylaminetrisulpho acid.
a
The melt is then dissolved in such a quantity of water and hydrochloric acid as
to form a saturated slightly acid salt solution, from which, on cooling, the acid
soda salt of the new amidonaphtholdisulpho acid separates in light grey crystalline
needles.
The new acid is readily soluble in cold and hot water; it yields no diazo
compound when treated with nitrite; with chloride of iron it produces a dark
green solution; combined with diazo or tetrazo compounds it yields dye stuffs, of
which especially the latter are of great practical value; the new acid combines
with only one molecule of a diazo body, and differs in this respect from the
isomeric amidonaphtholdisulpho acid mentioned in the Specification No. 13443
of 1890.
According to its formation and general properties the new acid is to be regarded
as a disulpho acid of 1:8 amidonaphthol.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what 1
claim is :-
1. The herein described process for manufacture of a new amidonaphtholdisulpho
acid and its salts by melting with caustic alkali the a naphthylaminetrisulpho acid,

page_text: which is obtained by sulphonation of the a naphthylaminedisulpho acid hereinbefore
referred to.
2. The amidonaphtholdisulpho acid and salts thereof manufactured as set forth
in the preceding claim.
Dated this 27th day of October 1893
ABEL & IMRAY,
Agents for the Applicant.