Improvements in the Manufacture of Azo Dyestuffs.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Azo Dyestuffs.
A communication from abroad by LA SOCIÉTÉ CHIMIQUE DES USINES DU RHÔNE,
anciennement GILLIARD 1. MONNET ET CARTIER, of Lyons, France,
Manufacturers.
I, GEORGE BELOE ELLIS, of the Firm of J. C. Mewburn & Ellis, of 55 and 50,
Chancery Lane, in the County of London, Chartered Patent Agents, do hereby
declare the nature of this invention to be as follows:-
The present invention relates to improvements in the manufacture of azo dye-
stuffs, particularly for use in printing fabrics.
In the preparation of azo dyestuffs, a phenol, or an amine is made to react with
a ready-formed diazo compound. The great tendency of diazo compounds to
decomposition renders however their preparation and copulation operations of
more or less difficulty, requiring extremely careful manipulation and maintenance
of a low temperature by use of large quantities of ice.
My foreign correspondents have now discovered that the manufacture of azo
dyestuffs is facilitated and rise of temperature avoided if a mixture of an amino
with a phenol or with a second amine, in slightly acid solution, is treated with a
thickened solution of nitrite. The resulting solution or suspension of azo dye-
stuff may be employed direct for printing fabrics, even in cases where the dye-
stuff prepared in the usual manner, cannot be employed on account of its insolu-
bility. According to the method now discovered, these dyestuffs are produced in
such an extremely fine state of division as to be fixed by the fibres without
trouble,
Apparently the presence of the thickening material so retards the reaction
that there is no rise of temperature and no decomposition, a quantitative yield
of the azo compound being obtained. If a mixture of two amines be employed
then of course the nature of the azo dyestuff produced depends upon which of the
two amines is most readily diazotized.
The following are examples of the manner in which the invention may be
carried out, but the invention is not limited to these examples and may be applied
to the production of a very wide range of azo dyestuffs, particularly to such as
on account of their relative insolubility have hitherto found little or no technical
employment.
1 nant hate-nonhthylamine nowder and
I.

page_text: If intended for cotton printing, ǝ parts tannin in 50 per cent. acetic acid
solution are added, and after steaming the fabric is passed through a tartar
emetic bath.
1 part anilin and
II.
2 parts alpha-oxynaphtoic acid are dissolved in
15 parts acetin and mixed with
100 parts thickening, to which is added 1 part of acetic acid of 60% or the
corresponding quantity of another suitable organic acid, and
7 parts 10 per cent. sodium nitrite solution.
This example is specially suitable for the production of insoluble azo dyestuffs.
1 part anilin and
2 parts alpha-oxynaphtoic acid are dissolved in
15 parts acetin and mixed with
100 parts thickening, to which is added 1 part of acetic acid of 60% or the
corresponding quantity of another suitable organic acid, and
7 parts 10 per cent. sodium nitrite solution.
This example is specially suitable for the production of insoluble azo dyestuffs.
15 parts acetin and mixed WICI
100 parts thickening, to which is added 1 part of acetic acid of 60% or the
corresponding quantity of another suitable organic acid, and
7 parts 10 per cent. sodium nitrite solution.
This example is specially suitable for the production of insoluble azo dyestuffs.
Improvements in the Manufacture of Azo Dyestuffs.
A communication from abroad by LA SOCIÉTÉ CHIMIQUE DES USINES DU RHONE,
anciennement GILLIARD P. MONNET ET CARTIER, of Lyons, France,
Manufacturers.
I, GEORGE BELOE ELLIS, of the Firm of J. C. Mewburn & Ellis, of 55 and 56,
Chancery Lane, in the County of London, Chartered Patent Agents, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following state-
ment:-
The present invention relates to improvements in the manufacture of azo dye-
stuffs, particularly for use in printing fabrics.
In the preparation of azo dyestuffs, a phenol or an amine is made to react with
a ready-formed diazo compound. The great tendency of diazo compounds to
decomposition renders however their preparation and copulation operations of
more or less difficulty, requiring extremely careful manipulation and maintenance
of a low temperature by use of large quantities of ice.
My foreign correspondents have now discovered that the manufacture of azo
dyestuffs is facilitated and rise of temperature avoided if a mixture of an amine
with a phenol or with a second amine, in slightly acid solution, is treated with a
thickened solution of nitrite. The resulting solution or suspension of azo dye-
stuff may be employed direct for printing fabrics, even in cases where the dye-
stuff prepared in the usual manner, cannot be employed on account of its insolu-
bility. According to the method now discovered, these dyestuffs are produced in
such an extremely fine state of division as to be fixed by the fibres without
trouble.
Apparently the presence of the thickening material so retards the reaction
that there is no rise of temperature and no decomposition, a quantitative yield
of the azo compound being obtained. If a mixture of two amines be employed
then of course the nature of the azo dyestuff produced depends upon which of the
two amines is most readily diazotized.
The following are examples of the manner in which the invention may be
carried out, but the invention is not limited to these examples and may be applied
to the production of a very wide range of azo dyestuffs, particularly to such as

page_text: 10 parts actin and mixed wICIL
100 parts thickening, to which is added 1 part of acetic acid of 60% or the
corresponding quantity of another suitable organic acid, and
74 parts 10 per cent. sodium nitrite solution.
This example is specially suitable for the production of insoluble azo dyestuff's.
Having now particularly described and ascertained the nature of the said
invention, as communicated to me, and in what manner the same is to be per-
formed, I declare that what I claim is:-
:-
1. An improved manufacture of insoluble azo dyestuffs consisting in treating
a mixture of an amine with a phenol or with a second amine, in slightly acid
solution, with a thickened solution of nitrite, substantially as described.
2. An improved manufacture of azo dyestuff's in a form particularly suitable for
printing fabrics consisting in treating a mixture of an amine with a phenol, or
with a second amine, together with sodium nitrite and a thickening material, with
an acid, preferably acetic acid, substantially as described.
Dated this 7th day of July 1899.
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London, Chartered Patent Agents.