Improvements in the Manufacture of Indigo.
Year: 1893

page_text: Date of Application, 27th Feb., 1893
Complete Specification Left, 4th Nov., 1893-Accepted, 9th Dec., 1893
PROVISIONAL SPECIFICATION.
[Communicated from abroad by KALLE & Co., of Biebrich on the Rhine, in the
Empire of Germany, Manufacturers.]
Improvements in the Manufacture of Indigo.
I, HENRY HARRIS LAKE, of the Firm of Haseltine Lake & Co., Patent Agents,
45 Southampton Buildings, London, W.C. do hereby declare the nature of this
invention to be as follows:-
As is well known the orthonitrophenyllactoketone described by Baeyer and
Drewsen (Ber. XV. 2856) is converted into indigo when treated with alkali. This
property however could not be technically utilized hitherto for the production of
indigo on the fibre, because in the first place the preparation of the ketone was
attended with difficulties and on the other hand because the said compound is not
sufficiently soluble in the usual solvents.
We have now succeeded in transforming the said ketone by a suitable treatment
with bisulphites into compounds which are readily soluble in water. We have thus
arrived at a process by which à pure product from the raw material is obtained
which is otherwise purified with great difficulty and at the same time we have found
a product which fulfils all technical requirements. The acqueous solutions of the
combinations of orthonitrophenyllactoketone with bisulphites give a precipitate of
ketone by the action of acids, while indigo is formed directly by mixing with an
excess of alkali.
.
Among the said compounds obtained with bisulphite of soda some possess most
valuable properties for use in dyeing and printing. We proceed for instance as
follows: 10 kilos. orthonitrophenyllactoketone are heated with 15 kilos. of a
solution of bisulphite of soda containing about 35% Na H.S.O, at from 50° to
55° centigrade. At this temperature the ketone is quickly dissolved and the new
compound crystallizes out in concentrically grouped needles or in white greasy-
glittering scales. This represents the commercial product either dried or in the paste
form. In order to produce indigo on the fibre the cloth is printed with the said
compound and the color is developed with alkalies, for instance with a caustic
soda lye of 18° 25° Baumé.
The application of the new compound presents great advantages over the
processes hitherto known. Goods printed with the same and passed through soda-
lye are distinguished by a purity of shade hitherto unequalled. They are always
completely and evenly dyed and therefore do not rub off. For printing purposes
only the propiolic acid process and the process of Schlieper and Baum were
hitherto known, compared with which the method of printing with the new com-
pound excels greatly in the simplicity of the process and the brightness of the
shades.
HASELTINE, LAKE & Co.,
45, Southampton. Buildings, London, W.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Indigo.
1, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent Agents,
45 Southampton Buildings in the County of Middlesex, 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 :-
As is well known the orthonitrophenyllactoketone described by Baeyer and

page_text: Drewsen (Ber. XV. 2856) is converted into indigo when treated with alkali. This
property however could not be technically utilized hitherto for the production of
indigo on the fibre, because in the first place the preparation of the ketone was
attended with difficulties and on the other hand because the said compound is not
sufficiently soluble in the usual solvents.
I have now succeeded in transforming the said ketone by a suitable treatment
with bisulphites into compounds which are readily soluble in water. I have thus
arrived at a process by which a pure product from the raw material is obtained
which is otherwise purified with great difficulty and at the same time I have found
a product which fulfils all technical requirements. The aqueous solutions of the
combinations of orthonitrophenyllactoketone with bisulphites give a precipitate of
ketone by the action of acids, while indigo is formed directly by mixing with an
excess of alkali.
Among the said compounds obtained with bisulphite of soda some possess most
valuable properties for use in dyeing and printing. I proceed for instance as
follows: 10 kilos. orthonitrophenyllactoketone are heated with 15 kilos. of a
solution of bisulphite of soda containing about 35% Na H.S.O, at from 50° to
55° centigrade. At this temperature the ketone is quickly dissolved and the new com-
pound crystallizes out in concentrically grouped needles or in white greasy-
glittering scales. This represents the commercial product either dried or in the
paste form. In order to produce indigo on the fibre the cloth is printed with the
said compound and the color is developed with alkalies, for instance with a caustic
soda lye of 18°-25° Baumé.
The application of the new compound presents great advantages over the pro-
cesses hitherto known. Goods printed with the same and passed through soda-lye
are distinguished by a purity of shade hitherto unequalled. They are always
completely and evenly dyed and therefore do not rub off. For printing purposes
only the propiolic acid process and the process of Schlieper and Baum were hitherto
known, compared with which the method of printing with the new compound excels
greatly in the simplicity of the process and the brightness of the sades."
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed as communicated to me by my
foreign correspondents, I declare that what I claim is :-
1. The production of compounds readily soluble in water by treating orthonitro-
phenyllactoketone with bisulphites.
2. The production of indigo on the fibre by treating it with the said com-
pounds and by developing the colour by means of alkalies or of suitable salts as for
instance the carbonates, silicates or borates of alkalies.
Dated this 4th day of November 1893.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.