Manufacture of Stable Double Salts of Chloride of Zinc and the Diazo or Tetrazo Compounds respectively of Amidoazo and Diamidoazo Compounds.
Year: 1896

page_text: Date of Application, 23rd Jan., 1896
Complete Specification Left, 22nd Oct., 1896-Accepted, 28th Nov., 1896
[Communicated from abroad by THE FARBWERKE, vormals MEISTER LUCIUS
AND BRUNING, of Hoechst a/Main, Germany, Chemical Manufacturers.]
Manufacture of Stable Double Salts of Chloride of Zinc and the
Diazo or Tetrazo Compounds respectively of Amidoazo and
Diamidoazo Compounds.
I, OLIVER IMRAY of No. 28 Southampton Buildings in the County of London,
Chartered Patent Agent, do hereby declare the nature of this invention to be as
follows:-
The application of diazotation, as well as the working with decomposable diazo
solutions, is known to offer no inconsiderable difficulties to the production of azo
dyestuffs insoluble in water, and the colour industry has been occupied for some
time with the task of manufacturing stable diazo compounds.
My correspondents have discovered that the diazo or tetražo compounds
respectively of amidoazo and diamidoazo substances can form double salts by
means of chloride of zinc, which, on account of their fastness, seem specially
suitable for application in the manufacture of dyes and lakes.
EXAMPLE II.
848 grammes paraamidobenzeneazo-a-naphthylamine are finely ground with
520 grammes of nitrite and 1800 cub. cm. water and the nitrite paste thus
obtained is gradually added to the mixture of 1280 cub. cm. of hydrochloric acid
of 22° Bé., 2400 cub. cm. water and 4800 grammes of ice.
After diazotation and disappearance of the foam, the solution is filtered, the
diazo compound precipitated by means of 400 grammes of a solution of chloride

page_text: of zinc (1 part chloride of zinc + 2 parts water) and the brown crystallised
residue is filtered and pressed.
Dated this 23rd day of January 1896.
ABEL & IMRAY,
Agents for the Applicant.
Manufacture of Stable Double Salts of Chloride of Zino and the
Diazo or Tetrazo Compounds respectively of Amidoazo and
Diamidoazo Compounds.
I, OLIVER IMRAY of No. 28 Southampton Buildings 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:-
The application of diazotation as well as the working with decomposable diazo
solutions, is known to offer no inconsiderable difficulties to the production of azo
dyestuffs insoluble in water, and the colour industry has been occupied for some
time with the task of manufacturing stable diazo compounds.
My correspondents have discovered that the diazo or tetrazo compounds
respectively of amidoazo and diamidoazo substances can form double salts by
means of chloride of zinc, which on account of their fastness, seem specially
suitable for application in the manufacture of dyes and lakes.
EXAMPLE I.
2100 grammes of amidoazobenzene are finely ground with
750 grammes nitrite and
5 litres water.
700 grammes of crystallised chloride of zinc, dissolved in 2 litres water.
The crystallised residue thus obtained is filtered pressed and dried if necessary.
EXAMPLE II.
848 grammes paraamidobenzeneazo-a-naphthylamine are finely ground with
520 grammes of nitrite and 1800 cub. cm. water and the nitrite paste thus
obtained is gradually added to the mixture of 1280 cub. cm. of hydrochloric acid
of 22° Bé., 2400 cub. cm. water and 4800 grammes of ice.
After diazotation and disappearance of the foam, the solution is filtered the
diazo compound precipitated by means of 400 grammes of a solution of chloride
of zinc (1 part chloride of zinc + 2 parts water) and the brown crystallised
residue is filtered and pressed.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is:-
Manufacture of stable double salts of chloride of zinc and the diazo or tetrazo-

page_text: compounds respectively of amidoazo and diamidoazo substances by precipitating
the diazo or tetrazo compounds respectively of amidoazo and diamidoazo bases from
their aqueous solutions by means of chloride of zinc, substantially as described.
Dated this 22nd day of October 1896.
ABEL & IMRAY,
Agents for the Applicant.