Manufacture of Alpha-amido-alizarine-sulphonic Acid.
Year: 1895

page_text: Date of Application, 21st Jan., 1895
Complete Specification Left, 21st Oct., 1895-Accepted, 23rd Nov., 1895
[Communicated from abroad by THE FARBWERKE, vormals MEISTER LUCIUS
AND BRUNING, of Hoechst a/Main, in the Empire of Germany, Chemical
Manufacturers.]
Manufacture of Alpha-amido-alizarine-sulphonic Acid.
I, OLIVER IMRAY, of No. 28 Southampton Buildings, Chancery Lane, in the
County of London, Chartered Patent Agent, do hereby declare the nature of this
invention to be as follows:-
My foreign correspondents have found that alpha-amido-alizarine obtained by
reducing alpha-nitro-alizarine (which is easily prepared according to the method
of the German Patent No. 66811) can, on treatinent with fuming sulphuric acid
be converted into a. sulphonic acid, soluble in water, which, on account of its
remarkable tinctorial properties, forms a valuable colouring matter.
On treating a-amido-alizarine with fuming sulphuric acid, the sulphonic acid is
not formed directly but an intermediate product, soluble with difficulty in cold
water, is formed in the first phase of the reaction, which on boiling with water or
dilute acids is converted into a-amido;alizarine-sulphonic acid.
The constitution of this intermediate product is probably that of an ether of
sulphuric acid' or that of a derivative of sulphamic acid. In order to prepare and
isolate the intermediate product the operation is as follows:-
.
a-amido-alizarine is heated with about ten times it's weight of fuming sulphuric
acid, containing from 20 to 40 per cent. of sulphuric anhydride, to a temperature of
from 100° to 140° C. until a test sample is found to be almost insolable in cold
water but, on boiling, to dissolve with a carmine red colour. The sulphuric acid
melt is poured on to ice and the precipitate is filtered from 'the' greater part of the
sulphuric acid. By washing with very dilute salt solution the product is obtained
neutral, and, in a dry state, forms a red brown crystalline powder not readily
soluble in cold water. It dissolves readily in dilute alkali with a red brown
colour.
In alkaline solution it is stable, is not changed by boiling and can be easily
salted out
Thus it is easy to effect the purification of the intermediate product by
dissolving it in very dilute bot soda solution and, after filtering, by precipitating
it cautiously with hydrochloric acid.
On boiling the intermediate product with water or dilute acids, it goes into
solution with a fine" carmine red colour. a-amido-alizarine sulphonic acid can be
easily isolated from this solution' by salting out with sodium chloride or potassium
chloride.
"
The manufacture of a-amido-alizarine sulphonic acid may thus be very easily
effected, without isolating the intermediate product, as follows:
1 kilo. a-amido-alizarine is dissolved in from 10 to 15 kilos. of fuming sulphuric
acid, containing from 20 to 40 per cent! of sulphuric anhydride, and heated from
100° to 140° C. until a test sample dissolves completely with fine, carmine' red
colour on being boiled with water.
After the melt has cooled down' it is poured into ice water, boiled up until all
bas dissolved with the characteristic red colour, filtered, and the sulphonic acid' is
isolated by salting out with sodium chloride or potassium chloride.

page_text: Its
After washing until the reaction is neutral, the sulphonic acid forms a blackish
brown powder which easily dissolves in water with carmine red colour.
solutions in alkalies exhibit a weak fluorescence. It dissolves in concentrated
sulphuric acid with yellowish red colour. The sulphonic acid is either insoluble
or very slightly soluble in the usual organic solvents such as alcohol, ether, glacial
acetic acid, aniline &c.
a-amido-alizarine-sulphonic acid is both an acid and a mordant dyestuff, and dyes
wool in an acid bath red with a blue tinge and wool, mordanted with chrome, prune
.colour.
The colours obtained in an acid bath can be afterwards tinted as required with
metallic mordants and, when developed with chromium fluoride, give a pure blue.
The colours developed with mordants exhibit the properties of the alizarine dyes
in their fastness to light and soap.
011
T
1005
ABEL & IMRAY,
Agents for the Applicant.
Manufacture of Alpha-amido-alizarine-sulphonic Acid.
I, OLIVER IMRAY, of No. 28 Southampton Buildings, Chancery Lane, in the
County of London, 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:-
My foreign correspondents have found that alpha-amido-alizarine obtained by
reducing alpha-nitro-alizarine (which is easily prepared according to the method
of the German Patent No. 66811) can, on treatment with fuming sulphuric acid be
converted into a sulphonic acid, soluble in water, which, on account of its remarkable
tinctorial properties, forms a valuable colouring matter.
On treating a-amido-alizarine with fuming sulphuric acid, the sulphonic acid is
not formed directly, but an intermediate product, soluble with difficulty in cold
water, is formed in the first phase of the reaction, which on boiling with water or
dilute acids is converted into a-amido-alizarine-sulphonic acid.
The constitution of this intermediate product is probably that of an ether of
sulphuric acid or that of a derivative of sulphamic acid. In order to prepare and
isolate the intermediate product the operation is as follows:-
a-amido-alizarine is heated with about ten times its weight of fuming sulphuric
acid, containing from 20 to 40 per cent. of sulphuric anhydride, to a temperature of
from 100° to 140° C. until a test sample is found to be almost insoluble in cold
water but, ou boiling, to dissolve with a carmine red colour. The sulphuric acid
melt is poured on to ice and the precipitate is filtered from the greater part of the
sulphuric acid. By washing with very dilute salt solution the product is obtained
neutral, and, in a dry state, forms a red brown crystalline powder not readily
soluble in cold water. It dissolves readily in dilute alkali with a red brown
colour.
In alkaline solution it is stable, is not changed by boiling and can be easily
salted out.
Thus it is easy to effect the purification of the intermediate product by dissolving
it in very dilute hot soda solution and, after filtering, by precipitating it cautiously
with hydrochloric acid.
On boiling the intermediate product with water or dilute acids, it goes into
solution with a fine carmine red colour, a-amido-alizarine, sulphonic acid can be
easily isolated from. this solution by salting out with sodium chloride or potassium
chloride.

page_text: The manufacture of a-amido-alizarine sulphonic acid may thus be very easily
effected, without isolating the intermediate product, as follows:
1 kilo. a-amido-alizarine is dissolved in from 10 to 15 kilos. of fuming sulphuric
acid, containing from 20 to 40 per cent. of sulphuric anhydride, and heated from
100° to 140° C. until a test sample dissolves completely with fine carmine red colour
on being boiled with water.
After the melt has cooled down it is poured into ice water, boiled up until all has
dissolved. with the characteristic red colour, filtered, and the sulphonic acid is
isolated by salting out with sodium chloride or potassium chloride.
After washing until the reaction is neutral, the sulphonic acid forms a blackish
brown powder which easily dissolves in water with carmine red colour. Its solutions
in alkalies exhibit a weak fluorescence. It dissolves in concentrated sulphuric acid
with yellowish red colour. The sulphonic acid is either insoluble or very slightly
soluble in the usual organic solvents such as alcohol, ether, glacial acetic acid,
aniline &c.
a-amido-alizarine-sulphonic acid is both an acid and a mordant dyestuff, and dyes
wool in an acid bath red with a blue tinge and wool, mordanted with chrome, prune
colour.
The colours obtained in an acid bath can be afterwards tinted as required with
metallic mordants and, when developed with chromium fluoride, give a pure blue.
The colours developed with mordants exhibit the properties of the alizarine dyes
in their fastness to light and soap.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The herein described manufacture of alpha amidoalizarine-sulphonic acid by
treating a-amidoalizarine with fuming sulphuric acid, containing from 20 to 40
per cent. of sulphuric anhydride, at a temperature of 100° to 140° C. until a test
sample dissolves clearly in hot water with carmine red colour, and by boiling with
water the resulting intermediate product, either isolated or not.
2. The a-amidoalizarine-sulphonic acid manufactured as above set forth.
Dated this 21st day of October 1805
ABEL & IMRAY,
Agents for Applicant.