Manufacture of Nitrated Colouring Matters.
Year: 1890

page_text: Date of Application, 28th Apr., 1890
Complete Specification Left, 15th Jan., 1891-Accepted, 21st Feb., 1891
PROVISIONAL SPECIFICATION.
[Communicated from abroad by LA SOCIÉTÉ ANONYME DES MATIÈRES
COLORANTES ET PRODUITS CHIMIQUES DE ST. DENIS, of 105, Rue
Lafayette, Paris, France.]
Manufacture of Nitrated Colouring Matters.
I, JOHN IMRAY, of No. 28, Southampton Buildings, Chancery Lane, in the
County of London, Consulting Engineer and Patent Agent, do hereby declare the
nature of this invention to be as follows :-
:―
This invention relates to the manufacture of certain colouring matters by treating
fuchsine, dimethylaniline violets, and methyline blue with a mixture of sulphuric and
nitric acids, in the following manner:
01
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40.75 kilo. of crystallised dimethylaniline violet are dissolved in 250 kilo. of
sulphuric acid at 66° Be.; the solution is cooled to 0° C., and to it is added in
successive doses a similarly cooled mixture of 10 kilo. of nitric acid at 63 % and
20 to 30 kilo. of sulphuric acid at 66°. The whole is left several hours in repose
and then poured into 4000 litres of water. The sulphuric acid is neutralised by
soda or carbonate of magnesia, and the base of the nitrated colouring matter, which
precipitates, is collected on a filter. To convert it into hydrochlorate, this base is
mixed with 110 to 120 kilo. of hydrochloric acid at 35% and the mixture is
evaporated to dryness.
The colouring matter is thus obtained in the form of powder having reddish
brown lustre, very soluble in water, which in a neutral or slightly acidulated bath
dyes violet blue, wool, silk and cotton with tannin mordant.
:
Instead of the 40.75 kilo. of the crystallised violet, from 39 to 39.5 kilo, of the
ordinary dimethylaniline violet or 375 kilo. of its base may be employed.
Benzylated violet, obtained by treating the above mentioned violets with benzyl
chloride gives by nitration a product not sensibly differing from those described.
For nitrated rosaniline, 33.75 kilo. of fuchsine or 32 kilo. of rosaniline are treated
in the same way as the dimethylaniline violet, giving a nitrated colour.which dyes
garnet, being preferably employed as a paste.
For nitrated methylene blue, 31.95 kilo. of methylene blue are employed instead
of the crystallised violet; the base of the colouring matter produced is dissolved in
hydrochloric acid and has bay salt added to it, whereupon is precipitated the nitrated
colouring matter which dyes bluish green.
By doubling the quantity of nitric acid, taking 20 kilo. instead of 10 kilo. in the
examples given, without otherwise changing the process, there are obtained nitrated
products generally less soluble in water but possessing the same dyeing properties,
with a slight difference of shade which is a little darker for the violet and the
fuchsine and more greenish for the nitrated methylene blue.
All these products have the advantage of not colouring the light parts of a
design produced by 'removal of the tannin mordant, and they resist soap and light
at least as well as the colouring matters whence they are derived.
Dated this 28th day of April 1890.
ABEL & IMRAY,
Agents for the Applicant:

page_text: COMPLETE SPECIFICATION.
Manufacture of Nitrated Colouring Matters.
1, JOHN IMRAY, of No. 28, Southampton Buildings, Chancery Lane, in the
County of London, Consulting Engineer and 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 :-
This invention relates to the manufacture of certain colouring matters by treating
fuchsine, dimethylaniline violets, and methyline blue with a mixture of sulphuric
and nitric acids, in the following manner:
40-75 kilo. of crystallised dimethylaniline violet are dissolved in 250 kilo. of
sulphuric acid at 66° Be.; the solution is cooled to 0° C. and to it is added in
successive doses a similarly cooled mixture of 10 kilo. of nitric acid at 63% and
20 to 30 kilo. of sulphuric acid at 66°. The whole is left several hours in repose
and then poured into 4,000 litres of water. The sulphuric acid is neutralised by
soda or carbonate of magnesia, and the base of the nitrated colouring matter,
which precipitates, is collected on a filter. To convert it into hydrochlorate, this
base is mixed with 110 to 120.kilo. of hydrochloric acid at 35 % and the mixture
is evaporated to dryness.
The colouring matter is thus obtained in the form of powder having reddish
brown lustre, very soluble in water, which in a neutral or slightly acidulated bath
dyes violet blue, wool, silk and cotton with tannin mordant.
Instead of the 40-75 kilo. of the crystallised violet, from 39 to 39.5 kilo. of the
ordinary dimethylaniline violet or 37.5 kilo. of its base may be employed.
Benzylated violet, obtained by treating the above mentioned violets with benzyl
chloride gives by nitration a product not sensibly differing from those described.
For nitrated rosaniline, 33.75 kilo. of fuchsine or 32 kilo. of rosaniline are treated
in the same way as the dimethylaniline violet, giving a nitrated colour which dyes
garnet, being preferably employed as a paste.
For nitrated methylene blue, 31.95 kilo. of methylene blue are employed instead
of the crystallised violet; the base of the colouring matter produced is dissolved
in hydrochloric acid and has bay salt added to it, whereupon is precipitated the
nitrated colouring matter which dyes bluish green.
By doubling the quantity of nitric acid taking 20 kilo. instead of 10 kilo. in the
examples given, without otherwise changing the process, there are obtained nitrated
products generally less soluble in water but possessing the same dyeing properties,
with a slight difference of shade which is a little darker for the violet and the
fuchsine and more greenish for the nitrated methylene blue.
All these products have the advantage of not colouring the light parts of a
design produced by removal of the tanning mordant, and they resist soap and light
at least as well as the colouring matters whence they are derived.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
1. The herein described process for nitrating to a greater or less degree fuchsine
and other colouring matters by treating them with mixtures of sulphuric and
nitric acids.
2. The nitrated colouring matters produced by the said process.
ABEL & IMRAY,
Agents for the Applicant.