Manufacture of Azo-dyes.
Year: 1895

page_text: Date of Application, 16th Feb., 1895
Complete Specification Left, 25th Oct., 1895-Accepted, 30th Nov., 1895
[Communicated from abroad by THE ACTIEN GESELLSCHAFT
FÜR ANILIN
FABRIKATION, of Berlin, in the Empire of Germany, Chemical Manu-
facturers.]
Manufacture of Azo-dyes.
I, JOHN IMRAY, 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:-
The combination of a a-amidonaphthol-a-mono-sulphonic acid with two mole-
cules of diazo bodies is the subject of several Letters Patent.
My foreign correspondents have now made the unexpected observation that,
under certain conditions, the a₁ a-amidonaphthol-a-monosulphonic acid is able to
combine with three molecular proportions of diazo compounds.
Those colouring matters which result by combining the said amidonaphthol-mono-
sulphonic acid with different diazo-compounds are especially interesting because it
is possible to choose the different components so as to exercise a certain influence
upon the tint and the solubility of the resulting colouring matters.
The mode in which the combinations are effected is of special importance, and,
according as the combinations are made, partly in alkaline or partly in weak acid
solution, products having different tinctorial powers and different tints are obtained.
So far as the researches reach, it is impossible to combine the aaamidonaphthol-a-
monosulphonic acid with the third molecular proportions of diazo compounds in
alkaline solution. To succeed with this third combination it is absolutely necessary
to perform this combination in weak acid solution.
My foreign correspondents have further found that it is of a great advantage,
especially in order to obtain a good yield, to effect the combination with the second
diazo body in weak acid, not in alkaline solution.
The first combination can be performed without disadvantage in alkaline or acid
solution, but the resulting products are not identical, and, in consequence of that,
the final products dye wool different tints according to the circumstances under
which the first combination is raade.
The following examples are given to illustrate how this invention can be
practically carried out.
has
15 kilos. of a-naphthylamine are diazotised in the usual way and the solution of
diazonaphthaline obtained is allowed to run into an icecold alkaline solution of
24 kilos. of a₁ a-amidonaphthol-a-monosulphonic acid. After the combination is
completed the whole is acidulated with acetic acid and combined again with the
same quantity of a-diazonaphthalene. As soon as the diazo-compound
disappeared, a solution of para-diazobenzolsulphonic acid, obtained from 19.5 kilos.
of sulphanilic acid is added, care being taken that the solution always remains
acetic acid. After 2 to 3 days the combination is completed by heating, and the
colouring matter is precipitated by means of salt, filtered and dried.
It dyes wool in an acid bath with violet-black shades.
If the first combination of the amidonaphthol-monosulphonic acid with the
diazonaphthaline be performed in acetic acid solution instead of an alkaline
solution, whilst the other combinations are carried out in the same manner as
described in the above example, a product is obtained which dyes wool greenish
black instead of blue-black.

page_text: A colouring matter which dyes wool between the two shades above mentioned
can be obtained when all three combinations are carried out in acetic acid solution,
and in the following order: amidonaphtholsulphonic acid is combined first with
a-naphthylamine, secondly with sulphanilic acid and lastly with a-naphthylamine.
If sulphanilic acid be chosen as the first component a product is obtained which 5
dyes wool more violet than black, and the yield of colouring matter is very
unsatisfactory.
It annears that the combination is not smoothly effected
I, JOHN IMRAY, 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 :-
The combination of a α-amidonaphthol-a-monosulphonic acid with two molecules
of diazo bodies is the subject of several Letters Patent.
My foreign correspondents. have now made the unexpected observation that under
certain conditions, the a, a-amido-naphthol-a-monosulphonic acid is able to combine
with three molecular proportions of diazo compounds.
Those colouring matters which result by combining the said amidonaphthol-
monosulphonic acid with different diazo compounds are especially interesting because
it is possible to choose the different components so as to exercise a certain influence
upon the tint and the solubility of the resulting colouring matters.
The mode in which the combinations are effected is of special importance, and,
according as the combinations are made, partly in alkaline or partly in weak acid
solution, products having different tinctorial powers and different tints are obtained.
So far as the researches reach, it is impossible to combine the σ a-amido-naphthol-
a-monosulphonic acid with the third molecular proportions of diazo compounds in
alkaline solution.
To succeed with this third combination it is absolutely necessary to perform this
combination in weak acid solution.
My foreign correspondents have further found that it is of a great advantage,
especially in order to obtain a good yield, to effect the combination with the second
diazo body in weak acid, not in alkaline solution.
The first combination can be performed without disadvantage in alkaline or acid
solution, but the resulting products are not identical, and, in consequence of that,
the final products dye wool different tints according to the circumstances under
which the first combination is made.
The following examples are given to illustrate how this invention can be practically
carried out.
EXAMPLE 1.
15 kilos. of a-naphthylamine are diazotised in the usual way and the solution of
diazonaphthaline obtained is allowed to run into an ice cold alkaline solution of
24 kilos. of a a-amidonaphthol a,-monosulphonic acid. After the combination is
completed the whole is acidulated with acetic acid and combined again with the
same quantity of a-diazonaphtbaline.
As soon as the diazo compound has disappeared, a solution of para-diazobenzol
sulphonic acid, obtained from 19.5 kilos. of sulphanilic acid is added, care being

page_text: taken that the solution always contains free acetic acid. After 2 to 3 days the
combination is completed by heating, and the colouring matter is precipitated by
means of salt, filtered and dried.
It dyes wool in an acid bath with violet black shades.
If the first combination of the amidonaphthol monosulphonic acid with the
diazonaphthaline be performed in acetic acid solution instead of an alkaline solution,
whilst the other combinations are carried out in the same manner as described in
the above example, a product is obtained which dyes wool greenish black instead of
blue-black.
A colouring matter which dyes wool between the two shades above mentioned
can be obtained when all three combinations are carried out in acetic acid solution,
and in the following order amidonaphtholsulphonic acid is combined first with
a-naphthylamine, secondly with sulphanilic acid and lastly with a-naphthylamine.
If sulphanilic acid be chosen as the first component a product is obtained which
dyes wool more violet than black, and the yield of colouring matter is very
unsatisfactory.
It annears that the combination is not smoothly effected
The intermediate product obtained by the action of 18.4 kilos. of tetrazotised
benzidine and 13.8 kilos. of salicylic acid is combined in a weakly alkaline solution
with 24 kilos. of alpha,-alpha-amidonaphthol-alpha-monosulphonic acid.
When the combination is completed, the solution is acidulated with acetic acid
and a solution of diazo naphthaline resulting from 14.4 kilos. of a-naphthylamine
is added.
After stirring for some time the combination is completed and a solution of the
diazo compound resulting from 19.3 kilos. of the sodium salt of sulphanilic acid is
allowed to flow in; this latter combination is carried out in presence of an excess

page_text: of acetic acid. The colouring matter thus formed is isolated in the usual manner.
It produces dark green shades on cotton from a salt or soap bath.
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 I
claim is :-
1. The herein described manufacture of azo dyes by combining one molecule of
alpha-alpha-amidonaphthol-alpha-monosulphonic acid with three molecules of
diazo compounds.