Manufacture of Cotton Dyestuffs.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Manufacture of Cotton Dyestuffs.
I, OLIVER IMRAY, of Birkbeck Bank Chambers, Southampton Buildings, in the
County of London, Chartered Patent Agent, do hereby declare the nature of this
invention (as communicated to me from abroad by The Farbwerke vormals
Meister Lucius & Brüning, of Hoechst "/Main, in the Empire of Germany,-
Chemical Manufacturers) to be as follows:-
-
A dyestuff directly dyeing cotton can be produced by subjecting the inter-
mediate product obtained in the manufacture of naphthazarin to the action of a
sulphide of an alkali metal.
My foreign correspondents have found that a dyestuff of similar properties
may be obtained from naphthazarin itself by heating it with a sulphide of an
alkali metal and zinc chloride. In this case the addition of zinc chloride is
necessary for the production of a dyestuff, whilst a dyestuff may be obtained from
the intermediate product referred to above even without zinc chloride.
The dyestuff obtained by heating naphthazarin with a sulphide of an alkali
metal and zinc chloride dyes cotton red-violet; if ammoniacal salts be added to
the mixture, a similar dyestuff of a more violet shade is obtained. The shades
of the dyestuffs obtained with or without ammoniacal salts become black when
treated with metallic salts.
EXAMPLE I.
A mixture of 30 parts by weight of naphthazarin, 150 parts by weight of
sodium sulphide, 30 parts by weight of sulphur, 15 parts by weight of zine
chloride of 40° Beaumé specific gravity and 150 parts by weight of water is
slowly evaporated to dryness and then heated to 160° to 180° C. until the colour
of the product no longer increases in intensity. The mass is then dissolved in
water and the solution is filtered and evaporated to dryness.
The dyestuff thus obtained is easily soluble in water, with a red-violet colour.
Mineral acids precipitate the acid of the dyestuff which is easily soluble in
alkaline carbonates or caustic alkalies.
EXAMPLE II.
A mixture of 30 parts by weight of naphthazarin, 150 parts by weight of
sodium sulphide, 30 parts by weight of sulphur, 15 parts by weight of zinc
chloride of 40° Beaumé specific gravity, 10 parts by weight of sal-ammoniac,
and 150 parts by weight of water is heated while actively stirring till the mass
becomes thick and then further heated for several hours to from 160° to 180° C.
until the intensity of colour no longer changes. The mass is then dissolved in
water and the solution is filtered and evaporated to dryness.
The concentrated solution of the dyestuff is deep-blue and violet when diluted.

page_text: Mineral acids separate the acid of the dyestuff as a blackish precipitate and
alkalies dissolve it with a blue colour.
Dated this 20th day of September 1899.
ABEL & IMRAY,
Agents for the Applicant.
I, OLIVER IMRAY, of Birkbeck Bank Chambers, Southampton Buildings, in the
County of London, Chartered Patent Agent, do hereby declare the nature of this
invention (as communicated to me from abroad by The Farbwerke vormals
Meister Lucius & Brüning, of Hoechst /Main, in the Empire of 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:-
-
A dyestuff directly dyeing cotton can be produced by subjecting the inter-
mediate product obtained in the manufacture of naphthazarin to the action of a
sulphide of an alkali metal.
My foreign correspondents have found that a dyestuff of similar properties
may be obtained from naphthazarin itself by heating it with a sulphide of an
alkali metal and zinc chloride. In this case the addition of zinc chloride is
necessary for the production of a dyestuff, whilst a dyestuff may be obtained from
the intermediate product referred to above even without zinc chloride.
The dyestuff obtained by heating naphthazarin with a sulphide of an alkali
metal and zinc chloride dyes cotton red-violet; if ammoniacal salts be added to
the mixture, a similar dyestuff of a more violet shade is obtained. The shades
of the dyestuffs obtained with or without ammoniacal salts become black when
treated with metallic salts.
EXAMPLE I.
A mixture of 30 parts by weight of naphthazarin, 150 parts by weight of
sodium sulphide, 30 parts by weight of sulphur, 15 parts by weight of zinc
chloride of 40° Beaumé specific gravity and 150 parts by weight of water is
slowly evaporated to dryness and then heated to 160° to 180° C. until. the colour
of the product no longer increases in intensity. The mass is then dissolved in
water and the solution is filtered and evaporated to dryness.
The dyestuff thus obtained is easily soluble in water, with a red-violet colour.
Mineral acids precipitate the acid of the dyestuff which is easily soluble in
alkaline carbonates or caustic alkalies.
EXAMPLE II.
A mixture of 30 parts by weight of naphthazarin, 150 parts by weight of
sodium sulphide, 30 parts by weight of sulphur, 15 parts by weight of zine
chloride of 40° Beaumé specific gravity, 10 parts by weight of sal-ammoniac,
and 150 parts by weight of water is heated while actively stirring till the mass
becomes thick and then further heated for several hours to from 160° to 180° C.
until the intensity of colour no longer changes. The mass is then dissolved in
water and the solution is filtered and evaporated to dryness.
The concentrated solution of the dyestuff is deep-blue and becomes violet when
diluted.

page_text: Mineral acids separate the acid of the dyestuff as a blackish precipitate and
alkalies dissolve it with a blue colour.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1. The herein described manufacture of a cotton dyestuff by heating naphtha-
zarin with or without ammoniacal salts, with sodium sulphide and zinc chloride.
2. The dyestuff manufactured as above set forth.
1000
ABEL & IMRAY,
Agents for the Applicant.