Manufacture of Leuco-derivatives of Gallocyanines.
Year: 1898

page_text: Manufacture of Leuco-derivatives of Gallocyanines.
I, JOHN IMRAY, of Birkbeck Bank Chambers, Southampton Buildings, Chancery
Lane, in the County of London, Consulting Engineer and Chartered Patent Agent,
do hereby declare the nature of this invention (as communicated to me from abroad
by La Société L. Durand Huguenin & Cie, of Hüningen, Alsace, Germany, Chemical
Manufacturers,) to be as follows:-
In the course of investigations respecting sulphite derivatives of oxazine (Patent
No. 6055 of 1898) my correspondents have found that, contrary to what might have
been expected, the leuco-gallocyanines possess certain advantages over the original
gallocyanines employed. Thus these leuco-derivatives, obtained by simple reduction
of the gallocyanines, give, when used for dyeing and printing, bluer and purer tints
than are given by the original gallocyanines employed; in addition, by the use of
these leuco-gallocyanines, in particular for printing, much stronger tints are obtained.
The hydrochlorides of these leuco-gallocyanines are much more readily soluble in
water than are the hydrochlorides of the gallocyanines from which they were
produced. These leuco gallocyanines are readily obtained by the usual methods of
chemical reduction, as for example with zinc, tin, stannous chloride, aluminium,
hydrosulphites, sodium stannite, glucose and soda lye, the sulphides of the alkali
metals, &c.
It is therefore unnecessary to give an example for each of the possible reducing
agents and I will limit myself to three examples that involve somewhat different
methods of operation.
EXAMPLE I.
33 kilos. of gallamine blue (gallocyanine obtained by the reaction of nitrosodimethyl-
aniline hydrochloride upon gallamic acid) or an equivalent quantity of another
gallocyanine, are suspended in 600 litres of luke warm water; 12 kilos. hydrochloric
acid are added, and then gradually, while strongly stirring, 20 kilos. of zinc dust, or
an equivalent quantity of another reducing agent operating in acid solution.
When the reduction is about completed, a further 20 kilos. of hydrochloric acid are
added (when using tin, all the acid inust be added in the first instance) and the mass
is heated to 80° to 90° C. and then filtered; from the filtered and cooled liquid the
leuco-derivative can be salted out.
For purifying this, it is again dissolved in warm water acidified with hydrochloric
This leuco-
acid, and after cooling, the leuco-derivative is again salted out.
gallocyanine forms a greenish mass which is formed into a paste with water, or it
can be dried.
It is soluble in water with a brownish green colour, and in concentrated sulphuric
acid with a dichroic claret red colour; by the addition of small quantities of oxidising
agents the colour of this solution in sulphuric acid passes over to intense blue.

page_text: EXAMPLE 11.
33 kilos. of ordinary gallocyanine or an equivalent quantity of another gallocyanine,
are suspended in 600 litres water; on the other hand, there are introduced, one after
the other, into an externally cooled vessel, 33 litres water, 33 kilos. sodium sulphite
of 38° Bé., 10 kilos. zinc dust, and, gradually, 14 kilos. hydrochloric acid. The
mixture thus formed is gradually added to the first named gallocyanine suspension.
When the reduction is about completed, there are added further 15 kilos.
hydrochloric acid, the mass is heated to about 80° C., filtered, cooled, and the leuco-
derivative salted out.
EXAMPLE III.
There are introduced consecutively into a closed vessel 400 litres warm water,
36 kilos. gallocyanine obtained by the reaction or nitrosodiethylaniline hydrochloride,
or diethyl-amido-azo-benzene hydrochloride upon gallamic acid, or an equivalent
quantity of another gallocyanine, and afterwards there are added 86 kilos. of a
10 per cent. solution of sodium sulphide (or an equivalent quantity of another
reducing agent, acting in alkaline solution) which has previously been mixed with a
solution containing from 24 to 30 per cent. of caustic soda, and a current of steam is
introduced into the apparatus while stirring, for heating the mass, and driving the
air out of the apparatus.
When dissolution is complete and the solution shows a dead brown coloration, the
liquid is poured into another receptacle containing 66 kilos. of hydrochloric acid
diluted in 100 litres of warm water, the vessel being connected with a chimney
flue.
The mass is strongly stirred, filtered, and the leuco-derivative is salted out.
I, JOHN IMRAY, of Birkbeck Bank Chambers, Southampton Buildings, Chancery Lane,
in the County of London, Consulting Engineer and Chartered Patent Agent, do hereby
declare the nature of this invention (as communicated to me from abroad by La
Société L. Durand Huguenin and Cie, of Hüningen, Alsace, Germany, Chemical
Manufacturers), and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :--
In the course of investigations respecting sulphite derivatives of oxazines
(Patent No. 6055 of 1898) my correspondents have found that, contrary to what
might have been expected, the leuco-gallocyanines possess certain advantages over
the original gallocyanines employed. Thus these leuco-derivatives, obtained by
simple reduction of the gallocyanines, give, when used for dyeing and printing,
bluer, purer tints than are given by the original gallocyanines employed, in addition,
by the use of these leuco-gallocyanines, in particular for printing, much stronger
tints are obtained.
The hydrochlorides of these leuco-gallocyanines are much more readily soluble in

page_text: water than are the hydrochlorides of the gallocyanines from which they were
produced.
These leuco-gallocyanines form a greenish mass which is formed into a paste with
water or it can be carefully dried. They are soluble in water with a brownish green
colour and in concentrated sulphuric acid with a dichroic brownish violet colour; by
the addition of small quantities of oxidising agents the colour of this solution in
sulphuric acid passes over to intense blue.
The leuco-gallocyanines are readily obtained by the usual methods of chemical
reduction, as for example with zinc, tin, stannous chloride, aluminium, sodium
stannite, glucose and soda lye, the sulphides of the alkali metals, &c. It is therefore
unnecessary to give an example for each of the possible reducing agents and I will
limit myself to two examples that involve somewhat different methods of
operation.
There are introduced consecutively into a closed vessel 400 litres warm water,
36 kilos. of the gallocyanine obtained by the reaction of nitrosodiethylaniline
hydrochloride, or diethyl-amido-azo-benzene hydrochloride upon gallanic acid, or an
equivalent quantity of another gallocyanine, and afterwards there are added 86 kilos.
of a 10 per cent. solution of sodium sulphide (or an equivalent quantity of another
reducing agent, acting in alkaline solution) which has previously been mixed
with 17 to 20 kilos. of a solution containing from 24 to 30 per cent. of caustic soda,
and a current of steam is introduced into the apparatus while stirring, for heating the
mass, and driving the air out of the apparatus.
When dissolution is complete and the solution shews a dead brown coloration, the.
liquid is poured into another receptacle containing 66 kilos. of hydrochloric acid
diluted in 100 litres of warm water, the vessel being connected with a chimney flue.
The mass is strongly stirred, filtered, and the leuco-derivative is salted out.
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 leucogallocyanines, or hydrogenised
gallocyanines, by treating a gallocyanine, dissolved or suspended in a liquid, with a
reducing agent which does not combine with the gallocyanine to form sulphurised
leuco-compound as described in the Specification No. 6055 of 1898.
2. The herein described manufacture of leucogallocyanines, or hydrogenised
gallocyanines, by treating a gallocyanine, dissolved or suspended in an acid with zinc,
tin, stannous chloride or aluminium.
3. The herein described manufacture of leucogallocyanines, or hydrogenised
gallocyanines, by treating a gallocyanine, dissolved or suspended in an alkali, with
sodium stannite, glucose or an alkali sulphide.

page_text: 4. Leucogallocyanines or hydrogenised gallocyanines manufactured as above set
forth.
ABEL & IMRAY,
Agents for the Applicant.