Improvements in the Manufacture of Raw Materials for Dye-stuffs.
Year: 1890

page_text: Date of Application, 1st Jan., 1890
Complete Specification Left, 1st Oct., 1890-Accepted, 1st Nov., 1890
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Raw Materials for
Dye-stuffs.
I, RICHARD JOHN FRISWELL, F.I.C., F.C.S., &c., a Director of Messrs. Brooke
Simpson & Spiller Limited, of Atlas Works, Hackney Wick, in the County of
Middlesex, Aniline Dye Manufacturers, do hereby declare the nature of this invention
to be as follows:-
I have discovered that azoxytoluidines, obtained by reduction of nitrotoluidines in
an alkaline medium, preferably with zinc dust in presence of caustic soda, can, easily
and without loss, be converted into the corresponding oxyazotoluidines, as follows:
The azoxytoluidine is dissolved in an excess of sulphuric acid, of gravity about 1-845,
and allowed to stand at temperatures of from 15° to 60° Centigrade for a period of
between 24 and 144 hours, the said azoxytoluidine then slowly changes into
oxyazotoluidine, practically without loss.
For instance if 10 lbs. of the azoxytoluidine m. p. 168° C., obtained by reducing the
nitrotoluidine m. p. 107° C., be dissolved in 100 lbs. concentrated sulphuric acid and
the solution allowed to stand at a temperature of 15° Centigrade, in 24 hours little or
no change will occur, but after that time oxyazotoluidine appears and continues to
increase, until, after the lapse of 100-140 hours, the conversion is complete.
The oxyazo-compound can be precipitated by dilution with water and obtained as
sulphate, that dissolved in the mother liquors being precipitated as base by the addition
of any convenient alkali.
Dated this First day of Yan 1800
AMBROSE MYALL,
21, Cockspur Street, S.W., Agent for the Applicant.
COMPLETE. SPECIFICATION.
Improvements in the Manufacture of Raw Materials for
Dye-stuffs.
I, RICHARD JOHN FRISWELL, F.I.C., F.C.S., &c. a Director of Brooke Simpson &
Spiller Limited of Atlas Works, Hackney Wick, in the County of Middlesex, Aniline
Dye Manufacturers, 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 object of my invention is to effect the preparation of oxyazotoluidine in a
novel and improved manner, and unaccompanied by loss from destructive changes
during the preparation, such oxyazotoluidine being intended for subsequent conversion
into dye-stuffs, or coloring matters.
I have discovered that azoxytoluidine, obtained in the well-known manner by the
reduction of nitrotoluidine in an alkaline medium, can easily, and without serious loss,
be converted into the corresponding oxyazotoluidine in the following manner.
The azoxytoluidine is dissolved in an excess of sulphuric acid of about 1-840
specific gravity, and allowed to stand at a temperature of from 15° to 60° Centigrade
for a period of time ranging between 24 and 140 hours, the said azoxytoluidine then
slowly changes into oxyazotoluidine, practically without loss.
As an instance of the foregoing process, if 10 lbs. of azoxytoluidine, of melting
point 168° Centigrade, obtained by reducing nitrotoluidine of melting point 107°
Centigrade, be dissolved in 100 lbs. of concentrated sulphuric acid, and the solution
be allowed to stand at a temperature of from 15° to 20° Centigrade, in 24 hours
little or no change will occur, but after that time oxyazotoluidine begins to appear
[Price 411

page_text: and continues to increase, until after the lapse of from 100 to 140 hours the con-
version is complete but I prefer to effect the conversion at or near a temperature
of 60° Centigrade, in which case the change is more rapid in all its stages and is
complete in a shorter time, about 72 hours being sufficient.
The oxyazo compound can be precipitated by dilution with water, and obtained in
the form of sulphate, which is almost insoluble in water. The mother liquors contain
small quantities of oxyazotoluidine and traces of unconverted azoxytoluidine as
sulphates, which can be recovered by suitable treatment, such as neutralization by
the addition of an alkali or alkaline carbonate.
The subsequent conversion into dye stuffs or coloring matters is effected in
accordance with any suitable method.
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 :-
The process for the production of oxyazotoluidine from azoxytoluidine, obtained by
the alkaline reduction of nitrotoluidine of melting point 107° Centigrade, by treat-
ment of the said azoxytoluidine with concentrated sulphuric acid at a temperature of
from 15° to 60° Centigrade and for a period of time ranging between 24 and 140 hours,
substantially as herein set forth.
Dated the 1st dave of O
1000
AMBROSE MYALL,
21, Cockspur Street, S.W., Agent for the Applicant.