Manufacture of Colouring Matters Capable of Dyeing Cotton Direct.
Year: 1893

page_text: COMPLETE SPECIFICATION.
[Communicated from abroad by the firm of KERN AND SANDOZ, of Båle,.
Switzerland, Manufacturers.]
Manufacture of Colouring Matters Capable of Dyeing Cotton Direct.
I, CHARLES DENTON ABEL, of 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:-
This invention relates to a manufacture of red azo colouring matters which dye
cotton without the use of mordants.
It has been discovered by my correspondents that on combining molecular
quantities of m. diethylaniline sulpho acid or of m. monoethylaniline sulpho acid on
the one hand, with tetrazo diphenyl or tetrazo ditolyl on the other hand, in alkaline
or acetic acid solution, intermediate products are produced which combine with
naphthylamine sulpho acids to form diazo coloring matters.
a
Particularly valuable are the products which are produced when the intermediate
products of m. diethylaniline sulpho acid and tetrazo diphenyl or tetrazo ditolyl are
brought together with naphthionic acid.
These colouring matters dye on cotton a ponceau-red colour in a neutral or weak
alkaline bath in pure and full tints. The colouring matters of monoethylaniline
sulpho acid are yellower and shew a somewhat less affinity for the vegetable
fibre.
=
The colouring matters of diethylorthotoluidine-sulpho acid have a brownish hue.
Under naphthylamine sulpho acid is to be understood the a naphthylamine-sulpho
acid of Piria (naphthionic acid 14) and the a naphthylamine sulpho acid of
Laurent (1-5). The colouring matters of the last named acid are soluble with
greater difficulty and are of a bluer tint than those of the isomeric naphthionic
acid.
The process for the preparation of the new colouring matters is generally as
follows: 1 equivalent of tetrazo diphenyl or tetrazo ditolyl is mixed with
1 equivalent of diethyl-aniline sulpho acid, mono-ethyl aniline sulpho acid, or
diethyl-orthotoluidine sulpho acid, in aqueous solution and the mixture is allowed
to stand in the presence of carbonate of soda or of acetate of soda until after the
termination of the combination. One equivalent of naphthionic acid or of naph-
thylamine sulpho acid of Laurent is then added, and the whole is left to itself for
some hours. The compound is then rendered alkaline, if necessary, is boiled, and
the colouring matter is then separated by salting and pressing.
The following will serve as an example for the manufacture.
a
A solution of tetrazo diphenylchloride, obtained from 14.2 kilos benzidine-
sulphate, 15 kilos hydrochloric acid of 30 p.c. HCl, and 7.2 kilos of sodium
nitrite of 96 p.c. NaNO,, is combined with an aqueous solution of 13 kilos diethyl-
aniline sulphonate of soda and 16 kilos of acetate of soda. After about 2 hours
the combination will be completed, and a solution of 18 kilos of naphthionate of
soda (of 70 p.c.) is added under stirring, after which the compound is allowed to
stand for two days at ordinary temperature.
The compound is then rendered alkaline by means of soda, is heated to boiling
point and the colouring matter is then precipitated by means of salt and separated
by filtration.
The colouring matter obtained dissolves very readily, even in cold water.
In concentrated sulphuric acid it dissolves with a blue colour, and on diluting
the solution with water it is precipitated in the form of red-violet flakes.

page_text: The colouring matter dyes cotton,without mordant in full ponceau-red tints and
is coloured violet by means of small quantities of acid.
If in the above example tetrazodiphenyl be replaced by the equivalent quantities
of tetrazo ditolyl a colouring matter of a somewhat more blueish hue and somewhat,
more acid proof, and also soluble with considerably greater difficulty in water, is
obtained.
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. A manufacture of intermediate products still containing a diazo group capable
of reaction, and applicable for the production of colouring matters, consisting in
the coupling of tetrazo-diphenyl or tetrazo ditolyl with a molecular quantity of
m. diethylaniline-sulpho acid, m. monoethylaniline-sulpho acid or m. diethylortho-
toluidine-sulpho acid, substantially as described.
2. A manufacture, of colouring matters that dye cotton directly a red colour by
coupling the intermediate products obtained as set forth in the preceding claim
with naphthionic acid or a naphthylamine sulpho-acid of Laurent, substantially
as described.
Dated this 20th day of February 1893.
ABEL & IMRAY,
Agents for the Applicant.