Improvements in the Manufacture of Blue Mordant Dyeing Colouring Matters
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
"Improvements in the Manufacture of Blue Mordant Dyeing
Colouring Matters."
I, JAMES YATE JOHNSON, of 47 Lincolns 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 & Soda Fabrik, of Ludwig-
shafen-on-Rhine in the Empire of Germany) to be as follows:-
:-
In a series of Patent specifications from my present foreign correspondents the
manufacture of blue mordant dyeing colouring matters from dinitro-anthraquinones
is described. Some of these are very well known in the dyeing trade as anthracene-
blues. In particular in the Specification of Letters Patent No. 13029 of 1892 the
treatment of partially reduced dinitro-anthrquinones with fuming sulphuric
acid for the production of soluble colouring matter and the conversion thereof into
comparatively insoluble dye are described. The partial reduction of the dinitro-
anthraquinone in the sulphuric acid melt by the addition of a suitable reducing
agent is also described in the said Specification.
My foreign correspondents have found that instead of using a reducing_agent
similar results can be obtained by making use of the reducing action of an electric
current of suitable strength and intensity.
Soluble or comparatively insoluble colouring matters are obtained according to
the conditions of the operation. The former can if desired be converted into the
comparatively insoluble products by treatment with less strong acids.
The operation is conveniently effected in the following manner. The dinitro-
anthraquinone to be employed is dissolved in fuming sulphuric acid at the ordinary
temperature in a cell containing the cathode. The anode is placed in concentrated
sulphuric acid (containing about ninety five per cent HL, SO,) separated from the
cathode cell by a suitable diaphragm.
The following examples will serve to further illustrate the nature of the inven-
PREPARATION OF A COLOURING-MATTER SOLUBLE IN WATER.
In the compartment of a suitable electrolytic cell containing the cathode mix about
ten parts of 14' ortho-dinitro-anthraquinone in about two hundred parts of fuming
sulphuric acid containing about forty per cent free anhydride (SO). Fill the
anode cell with concentrated sulphuric acid (containing about ninety-five per cent
H, SO). Pass through the cells an electric current of about eighty ampères per
square decimetre of active electrode surface. When the temperature of the mass
approaches one hundred degrees centrigrade, cool it, so that it does not rise above
this temperature. Continue the treatment until the dinitro-anthraquinone is all
dissolved, or practically so, and a test portion of the melt dissolves in concentrated
sulphuric acid giving a red colour, and in water giving a brown colour. Cool the

page_text: melt rapidly and pour into ice-water, then boil up and filter, precipitate by means
of common salt the colouring matter from the red filtrate; collect the chocolate-
brown precipitate by filtering, press and dry.
EXAMPLE 2.
CONVERSION OF THE SOLUBLE COLOURING-MATTER INTO A COMPARATIVELY
INSOLUBLE ONE.
Heat the soluble colouring matter obtained in accordance with the foregoing
example with ten times its weight of concentrated sulphuric acid (containing
about ninety-five per cent H, SO₁) in the manner described under b in the Specifica-
tion of Letters Patent No. 1958991. A comparatively insoluble mordant dyeing
colouring matter is obtained which can be worked up in the usual way.
EXAMPLE 3.
PREPARATION OF A COMPARATIVELY INSOLUBLE MORDANT DYEING COLOURING
MATTER.
If, in the foregoing example 1 the action of the electric current he continued 1
different products can be obtained. For instance continue the treatment with the
electric current at a temperature of about one hundred degrees centigrade until a
test portion of the melt dissolves with a brown colour in concentrated sulphuric
acid and on pouring into water produces a dark voilet precipitate. Cool the melt,
pour into ice-water collect the colouring matter on the filter and wash.
Instead of the 1-4 dinitro-anthraquinone other nitro-anthraquinones or mix-
tures thereof can be used.
Dated this 25th day of January 1897.
JOHNSONS & WILLCOX
47 Lincolns Inn Fields. London. W.C., Agents.
"Improvements in the Manufacture of Blue Mordant Dyeing
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 Badische Anilin & Soda Fabrik, of Ludwigshafen-
on-Rhine in the Empire of Germany) and in what manner the same is to be per-
formed to be particularly described and ascertained in and by the following state-
ment:-
In a series of Patent Specifications from my present foreign correspondents the
manufacture of blue mordant. dyeing colouring matters from dinitro-anthraquinones
is described. Some of these are very well known in the dyeing trade as anthracene-
blues. In particular in the Specification of Letters Patent No. 13029 of 1892 the
Treatment of partially reduced dinitro-anthraquinones with fuming sulphuric
acid for the production of soluble colouring matter and the conversion thereof into
comparatively insoluble dye are described. The partial reduction of the dinitro-
anthraquinone in the sulphuric acid melt by the addition of a suitable reducing
agent is also described in the said specification.
My foreign correspondents have found that instead of using a reducing agent
similar results can be obtained, by making use of the reducing action of an electric
current of suitable strength and intensity.

page_text: Soluble, or comparatively insoluble, colouring-matters are obtained according to
the conditions of the operation. The former can, if desired, be converted into tho
comparatively insoluble products by treatment with less strong acids.
The dinitro-
The operation is conveniently effected in the following manner.
anthraquinone to be employed is dissolved in fuming sulphuric acid at ordinary
temperature in a cell containing the cathode. The anode is placed in concentrated
sulphuric acid (containing about ninety-five per cent. H, SO) separated from the
cathode cell by a suitable diaphragm.
The following examples will serve to further illustrate the nature of the inven-
tion, and the manner in which it can be performed.
PREPARATION OF A COLOURING-MATTER SOLUBLE IN WATER.
In the cathode compartment of a suitable electrolytic cell mix about ten parts
(by weight) of 14-ortho-dinitro-anthraquinone with about two hundred parts of
fuming sulphuric acid containing about forty per cent. free anhydride (SO3). Fill
the anode cell with concentrated sulphuric acid (containing about ninety-five per cent.
H. SO). Pass through the cells an electric current of about eighty ampères
per square decimetre of active electrode surface. When the temperature of the
mass approaches one hundred degrees centigrade, cool it so that it does not rise
above this temperature. Continue the treatment until the dinitro-anthraquinone
is all dissolved, or practically so, and a test portion of the melt dissolves in concen-
trated sulphuric acid giving a red colour and in water giving a brown colour. Cool
the melt rapidly and pour into ice-water, then boil up and filter, precipitate by
means of common salt the colouring-matter from the red filtrate, collect the choco-
late-brown precipitate by filtering, press and dry.
EXAMPLE 2.
CONVERSION OF THE SOLUBLE COLOURING-MATTER INTO A COMPARATIVELY INSOLUBLE
COLOURING-MATTER.
Heat the soluble colouring-matter obtained in accordance with the foregoing
Example with ten times its weight of concentrated sulphuric acid (containing
about ninety-five per cent. H₂ SO) in the manner described under b in the Specifica-
tion of Letters Patent No. 19589 of 1891. A comparativly insoluble mordant
dyeing colouring-matter is obtained, which can be worked up in the usual way.
EXAMPLE 3.
PREPARATION OF A COMPARATIVELY INSOLUBLE MORDANT DYEING COLOURING-
MATTER.
If, in the foregoing Example 1 the action of the electric current be continued
different products can be obtained. For instance continue the treatment with the
electric current. at a temperature of about one hundred degrees centigrade until a
test portion of the melt dissolves with a brown colour in concentrated sulphuric acid
and on pouring into water produces a dark violet precipitate. Cool the melt,
pour into ice-water collect the colouring-matter on the filter and wash.
Instead of the 1.4-dinitro-anthraquinone other nitro-anthraquinones or mix-
tures thereof, can be used; namely, alpha- and delta-dinitro-anthraquinone, or
mixtures thereof with one another, or with 1.4'-dinitro-anthraquinone, such as,
for instance, are obtained by nitrating anthraquinone.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I declare that what I claim is: ---
1. In the manufacture of blue mordant-dyeing colouring-matters the reduction

page_text: of the dinitro-anthraquinone employed by means of electricity; substantially in the
manner herein before described.
2. The manufacture of blue mordant-dyeing colouring-matters, soluble in water,
by reducing the dinitro-anthraquinones herein before defined by treatment with
an electric current until the dinitro-anthraquinone is all, or practically all dissolved,
and until a test portion of the melt dissolves in concentrated sulphuric acid giving
a red colour and in water giving a brown colour substantially as hereinbefore de-
scribed.
3. The improvement in the manufacture of blue mordant dyeing colouring-
matters insoluble in water by reducing the dinitro-anthraquinone hereinbefore
defined by treatment with an electric current until a test portion of the melt dissolves
with a brown colour in concentrated sulphuric acid and on pouring into water
produces a dark violet precipitate substantially as herein before described.
4. The improvement in the manufacture of comparatively insoluble blue mordant
dyeing colouring-matters consisting in first preparing the blue colouring-matters
soluble in water as hereinbefore described and claimed in the second claiming
clause and then treating them with concentrated sulphuric acid substantially as
hereinbefore described.
5. The manufacture and production of blue mordant dyeing colouring-matters
in the manner described in the foregoing examples.
Dated this 16th day of October 1897
JOHNSONS & WILLCOX
47 Lincoln's Inn Fields, London, W.C. Agents.