Manufacture of Coloring Matters Derived from Pyrogallic Acid, and their Application to Dyeing and Printing.
Year: 1891

page_text: Date of Application, 23rd Feb., 1891-Accepted, 18th Apr., 1891
LEICE
COMPLETE SPECIFICATION.
Manufacture of Coloring Matters Derived from Pyrogallic Acid, and
their Application to Dyeing and Printing.
We, JEAN CLAUDE LOUIS DURAND, DANIEL EDOUARD HUGUENIN and
ADOLPHE JEAN JAMES D'ANDIRAN-KOECHLIN, constituting the firm of La
Societé L. Durand Huguenin & Cie., of Bâle, Switzerland, Manufacturers, 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:—
Our invention relates to a manufacture of new coloring matters by the action of
certain diazo and tetrazo compounds upon pyrogallic acid.
The diazo compounds which we employ are the diazo derivatives of aniline,
paranitraniline, metanitraniline, amidoazobenzol, and its monosulpho-conjugated
derivative.
The tetrazo compounds which we employ are the tetrazo derivatives of thio-
aniline, and thioparatoluidine.
These bodies are made to act in the proportion of their molecular weights; but
in order that our invention may be readily understood we will describe by way of
example the production of coloring matters resulting from the action of a diazo-
derivative and a tetrazo-derivative upon pyrogallic acid.
Example I. 13.800 kilos. of paranitraniline dissolved in 300 kilos. of water and
55 kilos. of muriatic acid of 20° Bé., are diazotised according to the well known
method with 7 kilos. of nitrite of soda of 100 per cent.
On the production of the diazo-derivative, the whole is poured into an aqueous
solution, maintained cold, of 12.6 kilos. of pyrogallic acid, to which is previously
added acetate of soda in sufficient quantity to saturate the excess of muriatic acid
used in the diazotation. There is thus produced a brown coloring matter which is
precipitated in the form of a brown powder, insoluble in acid water, soluble in
alkaline water, and dissolving in concentrated sulphuric acid, giving a red brown
coloration, which assumes a yellowish tint on the addition of water, by which
addition the coloring matter is precipitated. The solution of the coloring matter
in soda produces a bluish tint which is changed to red-brown again on the addition
of water. The product is filtered, washed, pressed, and, if desired, dried; it is
preferable however to keep it in the form of paste.
Example 11. 21 6 kilos. of thioaniline, dissolved in water to which has been
added muriatic acid as above stated, and diazotised with from 13.8 kilos. to 14 kilos.
of nitrite of soda, are added to 25.2 kilos. of pyrogallic acid dissolved in water con-
taining the quantity of acetate of soda necessary for the saturation of the excess of
muriatic acid used.
The colouring matter is precipitated, filtered, washed and pressed.
The brown colouring matters thus obtained will dye to a slight extent upon
unmordanted wool and silk in an acid bath, but they are particularly useful for
dyeing wool mordanted with metallic mordants.
The tints obtained with mordants of chromium and iron for example, possess
great depth and brightness and allow of obtaining deep tints, passing nearly to
black. These tints resist the action of air, soap and the most severe fulling, and
will combine with other colours that dye on metallic mordants.
In printing, these new coloring matters also give strong full bodied tints in
particular on cotton.
The tints of the coloring matters obtained by the new process vary only to a
slight extent, according to the diazo or tetrazo derivative employed.

page_text: 3, With metanitraniline
4, With amidoazobenzole
5, With monosulpho conjugated
amidoazobenzole
6, With thioaniline
7, With thiotoluidine
-
a brown with yellowish lustre.
a red-yellow.
a slightly yellower brown than.
the foregoing.
a yellowish brown.
a brown more red than the
preceding.
The above indicated tints are obtained with dye baths having 2 per cent. of
colouring matter; with dye baths having only 1 per cent. of coloring matter lighter
tints are obtained; with baths having 3 per cent. dark brown tints are obtained,
and with baths having 5 per cent. and more of coloring matter brown-black or
black-brown tints will be obtained.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
1. The herein described process for the production of new coloring matters by
the action of certain, diazo or tetrazo derivatives upon pyrogallic acid.
2. The new coloring matters produced as herein described.
3. The use of the herein described new coloring matters for dyeing and printing,
substantially as described.
Dated this 23rd day of February 1891
ABEL & IMRAY,
Agents for the Applicants.