Production of Red Dye from Para-nitro-aniline.
Year: 1894

page_text: Date of Application, 14th June, 1894
Complete Specification Left, 14th Mar., 1895-Accepted, 20th Apr., 1895
[Communicated from abroad by THE FARBWERKE, vormals MEISTER LUCIUS
AND BRUNING, of Hoechst a/ Main, in the Empire of Germany, Chemical
Manufacturers.]
Production of Red Dye from Para-nitro-aniline.
1. OLIVER IMRAY, of No. 28 Southampton Buildings, Chancery Lane,
in the County of London, Chartered Patent Agent, do hereby declare the nature
of this invention to be as follows:-
In July 1889 my foreign correspondents published a method of producing
a beautiful and fast red on cotton fibre, by means of para-nitro-aniline and
B-naphthol. The compound itself is an ugly orange which sublimes off the fibre so
rapidly at ordinary tenperatures that it is not applicable for dyeing and printing
purposes.
They obtained, however, a red of great beauty and fastness, by the addition of
oil in a soluble form to the solution of ẞ naphtholate of sodium with which the
fabric is previously impregnated. For this purpose, ricinoleate of sodium or the
sodium compound of the so called Turkey red oil, obtained by the sulphonation of
castor oil, proved the most suitable.
After padding with this mixture and drying, the material is dyed in the usual
way, by being passed through a solution of diazotised para-nitro-aniline, and is then
washed and soaped.
The method is particularly suitable for the production of even red colours, less
suitable however for red with a white reserve. While the orange obtained
without oil gives good white reserves, a white is obtained not so good when oil is
present.
Their object was therefore to obtain a substitute for the latter, by means of
which a red as beautiful and as easily reservable may be produced.
My correspondents have now found that the production of brilliant bluish red
tints may be accomplished by substituting for the fatty acid compounds in the
naphthol grounding other organic substances. The best results are obtained with
gum tragacanth or with gelatine, but other substances which are used in the
preparation of thickenings are also suitable; for instance, starch, meal, natural
gums, as well as artificial dextrinous substitutes for gum.
The addition of the above named substances to the sodium naphtholate solution
effects a better fixing of the sodium naphtholate as well as the production of a
bluish tint.
The red obtainable in this manner may be easily reserved with tin chloride or
with sodium sulphite, and it is possible to obtain a faultless white, in contrast to the
method formerly known, in which the oil combined with the fibre (fatty acids and
sulphonated fatty acids) tenaciously retained yellow decomposition products of the
diazo compound. The addition of gum tragacanth or its equivalents also protects
the fibre from corrosion by the concentrated tin chloride reserve.

page_text: To 4 kilos. ẞ naphthol, 44 kilos. caustic soda 40° Be. and 75 litres hot water
are added, after solution has taken place, 35 litres gelatine solution containing
60 grammes gelatine per
litre.
The goods prepared with these solutions are then dyed or printed in the usual way
with diazo solution.
To obtain white reserves, the material prepared with sodium naphtholate is
printed according to the above examples with tin chloride or sodium or potassium
sulphite, before developing with the diazo solution.
Dated this 14th day of June 1894.
ABEL & IMKAI,
Agents for the Applicant.
Production of Red Dye from Para-nitro-aniline.
I, OLIVER IMRAY, of No. 28 Southampton Buildings, Chancery Lane,
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 :-
In July 1889 my foreign correspondents published a method of producing a
beautiful and fast red on cotton fibre, by means of para-nitro-aniline and
B-naphthol. The compound itself is an ugly orange which sublimes off the fibre
so rapidly at ordinary temperatures that it is not applicable for dyeing and printing
purposes.
They obtained, however, a red of great beauty and fastness, by the addition of
oil in a soluble form to the solution of B-naphtholate of sodium with which the fabric
is previously impregnated. For this purpose, ricinoleate of sodium or the sodium
compound of the so called Turkey red oil, obtained by the sulphonation of castor
oil, proved the most suitable.
After padding with this mixture and drying, the material is dyed in the usual
way, by being passed through a solution of diazotised para-nitro-aniline, and is then
washed and soaped.
The method is particularly suitable for the production of even red colours, less
suitable however for red with a white reserve. While the orange obtained
without oil gives good white reserves, a white is obtained not so good when oil is
present.
Their object was therefore to obtain a substitute for the latter, by means of
which a red as beautiful and as easily reservable may be produced.
My correspondents have now found that the production of brilliant bluish red
tints may be accomplished by substituting for the fatty acid compounds in the
naphthol grounding, other organic substances. The best results are obtained with
gum tragacanth or with gelatine, but other substances which are used in the
preparation of thickenings are also suitable; for instance, starch, meal, natural
gums, as well as artificial dextrinous substitutes for gum.
The addition of the above named substances to the sodium naphtholate solution
effects a better fixing of the sodium naphtholate as well as the production of a
bluish tint.
The red obtainable in this manner may be easily reserved with tin chloride or
with sodium sulphite, and it is possible to obtain a faultless white, in contrast to the
method formerly known, in which the oil combined with the fibre (fatty acids and
sulphonated fatty acids) tenaciously retained yellow decomposition products of the
.

page_text: diazo compound. The addition of gum tragacanth or its equivalents also protects
the fibre from corrosion by the concentrated tin chloride reserve.
To 4 kilos. ẞ naphthol, 44 kilos. caustic soda 40° Bé. and 75 litres hot water,
are added, after solution has taken place, 35 litres gelatine solution containing
60 grammes gelatine per litre.
The goods prepared with these solutions are then dyed or printed in the usual
way with diazo solution.
To obtain white reserves, the material prepared with sodium naphtholate is
printed according to the above examples with tin chloride or sodium or potassium
sulphite, before developing with the diazo solution.
Having now particularly described and ascertained the nature of this inveu-
tion and in what manner the same is to be performed, I declare that what I
claim is:
The herein described process for dyeing or printing cotton red by grounding it
with B-naphthol and soda mixed with solutions of gum tragacanth, glue, gelatine,
gum or dextrinous substitutes for gum, wheat starch or meal, without adding oil,
and dyeing or printing on the cotton material so grounded with the diazo solution
of para-nitro-aniline.
...
7
1 100-
ABEL & IMRAY,
Agents for the Applicant.