Improvements in the Manufacture of Colouring Matters.
Year: 1893

page_text: Date of Application, 6th Oct., 1893
Complete Specification Left, 6th July, 1894-Accepted, 6th Oct., 1894
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Colouring Matters.
1, JAMES YATE JOHNSON of No. 47 Lincoln's Inn Fields in the County of
Middlesex Gentleman do hereby declare the nature of this invention (which has
been communicated to me from abroad by The Badische Anilin and Soda Fabrik of
Ludwigshafen on Rhine in the Empire of Germany) to be as follows :—
In the Specification of Letters Patent No. 4513 of 1891 granted to me on a
communication of my foreign correspondents, there are described new or improved
dye stuffs which are the soluble salts or compounds with acids of safranine-azo-
naphthol bodies.
These dyes have been introduced into commerce under the name of Indoin-blue
and are of great value to the dyer for they afford a perfect substitute for indigo in
some of its applications.
Impure safranine-azo-naphthols had already been prepared at the date of the
abovementioned Letters Patent but they were insoluble and therefore were
regarded as useless bodies.
Now my foreign correspondents have discovered that these insoluble safranine-
azo-naphthol bodies can be converted into a soluble Indoin blue dye by a new
process. As aforesaid the Indoin blues hitherto produced were salts or acid
compounds of safranine-azo-naphthols and they were prepared by the action of
acids on the said azo-bodies. Now the present invention is based upon the discovery
by my foreign correspondents that these azo-bodies can be converted into soluble
dyes (suitable for dyeing and printing and practically equivalent to Indoin blue in
all respects) by prolonged washing of the safranine-azo-naphthols whereby these
hitherto useless bodies become changed from the insoluble form in which alone they
were hitherto known into soluble basic dyes of great value.
The following example will serve to further illustrate the nature of the invention
but it can be varied as to details. Make a one per cent. solution of safranine taking
one molecular proportion of the safranine used, that is to say, about seven (7) parts of
safranine T, (obtained by the oxydation of a mixture of one molecular proportion
of toluylendiamine, one molecular proportion of ortho toluidine, and one molecular
proportion of auiline) or the equivalent quantity of another easily diazotisable
safranine such as pheno-safranine or dimethyl-safranine, and diazotize by adding
first a solution of sodium nitrite containing about fourteen (14) parts of that salt
(one molecular proportion) and then twenty three (23) parts of hydrochloric
acid containing about thirty per cent. real acid (30% HCI).
during these operations must be kept cold with ice and stirred.
the mixture into an ice-cold solution of about three (3) parts of either
alpha or beta naphthol (one molecular proportion) in about one hundred and
sixty (160) parts of water and twenty five parts (25) of caustic soda solution,
containing about thirty five per cent. (35%) of sodium hydrate (NaOH). Instead
of the above mentioned quantity of caustic soda merely the quantity necessary for
dissolving the naphthol can be used and the remainder can be replaced by the
equivalent quantity of an alkaline-carbonate.
The solution
Next run
The products thus obtained are washed with water and the washing continued
until the wash water becomes deeply coloured, and thereby indicates that the product
at first insoluble is rendered soluble.

page_text: The paste remaining on the filter is then made up to any convenient standard
strength and is ready for use.
Dated the 6th day of October 1893.
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Colouring Matters.
I, JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of London
Gentleman, do hereby declare the nature of this invention (which has been com-
municated to me from abroad by The Badische Anilin and Soda Fabrik of
Ludwigshafen on Rhine in the Empire of Germany) and in what manner the
same is to be performed to be particularly described and ascertained in and by the
following statement:-
In the Specification of Letters Patent No. 4543 of 1891 granted to me on a
communication from my foreign correspondents new or improved dyestuffs are
described which dyestuffs are the soluble salts or compounds with acids of
safranine-azo-naphthol bodies.
These dyes have been introduced into commerce under the name of Indoin-blue
and are of great value to the dyer for they afford a perfect substitute for indigo
in some of its applications.
Impure safranine-azo-naphthols had already been prepared at the date of the
abovementioned Letters Patent, but they were insoluble and therefore were
regarded as useless bodies, and were not applied commercially in any way.
Now my foreign correspondents have discovered that these insoluble safranine-
azo-naphthol bodies can be converted into a soluble Indoin-blue dye by a new
process as hereinafter explained. As aforesaid the Indoin-blues hitherto produced
were salts or acid compounds of safranine-azo-naphthols, and they were prepared
by the action of acids on the said azo-bodies. My foreign correspondents have
found that these azo-bodies can be converted into soluble dyes (suitable for
dyeing and printing and practically equivalent to Indoin-blue in all respects) by
washing the impure safranine-azo-naphthols with water and prolonging this washing
until these hitherto useless bodies become changed from the insoluble form, in
which alone they were hitherto known, into soluble basic dyes of great value.
The following example will serve to further illustrate the nature of the invention
and the manner in which it can be carried into practical effect but it can be
varied as to details for any operation which, frees the safranine-azo-naphthol from
an excess of alkali, and from salts, yields the same products.
Make a one per cent. solution of safranine, taking one molecular proportion of
the safranine used, that is to say about seven parts of safranine T-(obtained by
oxydation of a mixture of one molecular proportion of toluylendiamine, one
molecular proportion of ortho-toluidine and one molecular proportion of aniline)-
or the equivalent quantity of another easily diazotisable, safranine, such as pheno-
safranine, or dimethyl-safranine, and diazotise by adding first a solution of sodium
nitrite, containing about fourteen parts of that salt (one molecular proportion),
and then twenty three parts of hydrochloric acid, containing about thirty per cent.
real acid (HCI). The solution during these operations must be kept cold by
means of ice and stirred. Next run the mixture into an ice cold solution of
about three parts of either alpha, or beta, naphthol, (one molecular proportion) in
about one hundred and sixty parts of water and twenty five parts of caustic soda
solution, containing about thirty five per cent. of sodium hydrate (NaOH). Instead
of the above mentioned quantity of caustic soda merely the quantity necessary for
dissolving the naphthol can be used and the remainder can be replaced by the
equivalent quantity of an alkaline carbonate.

page_text: The products thus obtained are washed with water, either in the usual way on
the filter, or by removing from the filter and stirring with water and then filtering
again. The washing is continued until the wash water becomes deeply coloured, or
until the product at first insoluble is rendered soluble.
The washed paste remaining on the filter is then made up to any convenient
standard strength and is ready for use.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
:-
1. The manufacture of colouring matters by subjecting the insoluble safranine
azo naphthols to a process which frees them from impurity and thereby renders
them soluble in water.
2. The manufacture of colouring matters by subjecting impure safranine azo
naphthols to prolonged washing with water substantially as herein before described.
3. The manufacture of colouring matters by the process herein before described
in the example.
JOHNSONS & WILLCOX,
Agents.