Manufacture of Orange Colouring Matters by Electro-chemical Process.
Year: 1895

page_text: Date of Application, 25th Nov., 1895
Complete Specification Left, 9th Dec., 1895-Accepted, 18th Jan.,
1896
Communicated from abroad by THE SOCIETY OF CHEMICAL INDUSTRY IN
BASLE, of Basle, Switzerland, Chemical Manufacturers.]
Manufacture of Orange Colouring Matters by Electro-chemical
Process.
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 :—
If the yellow alkaline condensation products of para nitro toluol sulpho acid,
which are considered to be azoxy azo, and dinitroso stilben disulpho derivatives,
are subjected in alkaline solution to electro chemical reduction, by protecting the
solution of the colouring matter by a porous partition from contact with the anode,
the yellow colouring matters are transformed into orange colouring matters.
The current is cut off as soon as the desired change in tint takes place, that is
to say, when a test-sample of the dye-stuff solution, diluted with 20 to 30 parts of
water, produces on filtering paper a red spot without any yellow traces.
In continuing the reduction process, the orange colouring matters first obtained
are destroyed, forming diamido stilben disulpho acid.
If solid cathodes of platinum, nickel, iron, carbon or the like are employed, a
higher temperature, for instance 98° to 100° C, is necessary; when mercury cathodes
are employed, the reaction is more complete with less expenditure of current at a
temperature of 40° to 60° C.
Dilute soda lye is the liquid best suited for both anodes and cathodes. For the
seda however may be substituted caustic alkali, hydrate of baryta or hydrate of
lime.
Instead of a complete solution of the colouring matter, fine emulsions of it may
be used.
It is not necessary to isolate first the condensation products of para nitro toluol
sulpho acid, but the mass of the reaction with caustic alkalies may be subjected
directly to electro chemical conversion.
The intensity of the electric current may vary between 3 and 30 ampères
per dm².
The best will be to have 5 to 15 ampères per dm³.
The following is an example of the process.
10 parts of para nitro toluol sulphonate of soda are condensed in the usual way
in an aqueous solution with 30 parts of soda lye of 30° Bé.
Afterwards the mass of condensation is diluted with about 70 parts of water and
reduced at about 45° C. by means of a mercury cathode, until the desired degree
of transformation is attained. The reaction liquid is then neutralized and by
It is filtered and
precipitation with common salt, the dye stuff is obtained.
dried. The colouring matter is a dark brown powder, easily soluble in water
with a yellow red colour, in concentrated sulphuric acid with a dark violet blue
colour.

page_text: In a neutral or alkaline bath it dries unmordanted cotton with orange tints
which are fast to air, chlorine and acids.
Dated this 25th day of November 1895.
ABEL & IMRAY,
Agents for the Applicant.
.
Manufacture of Orange Colouring Matters by Electro-chemical
Process.
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 :—
If the yellow alkaline condensation products of para nitro toluol sulpho acid,
which are considered to be azoxy azo, and dinitroso stilben disulpho derivatives,
are subjected in alkaline solution to electro chemical reduction, by protecting
the solution of the colouring matter by a porous partition from contact with
the anode, the yellow colouring matters are transformed into orange colouring
matters.
The current is cut off as soon as the desired change in tint takes place, that is
to say, when a test-sample of the dye-stuff solution, diluted with 20 to 30 parts of
water, produces on filtering paper a red spot without any yellow traces.
In continuing the reduction process, the orange colouring matters first obtained
are destroyed, forming diamido stilben disulpho acid.
If solid cathodes of platinum, nickel, iron, carbon or the like are employed, a
higher temperature, for instance 98° to 100° C., is necessary; when mercury cathodes
are employed, the reaction is more complete with less expenditure of current at
a temperature of 40° to 60° C.
Dilute soda lye is the liquid best suited for both anodes and cathodes. For the
soda however may be substituted caustic alkali; hydrate of baryta or hydrate of
lime.
Instead of a complete solution of the colouring matter, fine emulsions of it may
be used.
It is not necessary to isolate first the condensation products of para nitro toluol
sulpho acid, but the mass of the reaction with caustic alkalies may be subjected
directly to electro chemical conversion.
The intensity of the electric current may vary between 3 and 30 ampères
per dm³.
The best will be to have 5 to 15 ampères per dm³ (square decimetre of cathode
area).
The following is an example of the process.
10 parts of para nitro toluol sulphonate of soda are condensed in the usual
way in an aqueous solution with 30 parts of soda lye of 30° Bé.
Afterwards the mass of condensation is diluted with about 70 parts of water and
reduced at about 45° C. by means of a mercury cathode, until the desired degree
of transformation is attained. The reaction liquid is then neutralized and by
precipitation with common salt, the dye stuff is obtained. It is filtered and
dried. The colouring matter is a dark brown powder, easily soluble in water
with a yellow red colour, in concentrated sulphuric acid with a dark violet blue
colour.
In a neutral or alkaline bath it dies unmordanted cotton with orange tints which
are fast to air, chlorine and acids.

page_text: 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 hereindescribed manufacture of orange colouring matters by electro-
chemical reduction of the yellow condensation products of para nitro toluol
Bulpho acid.
2. The orange colouring matters produced as above set forth.
ABEL & IMRAY,
Agents for the Applicant.