IMPROVEMENTS IN THE MANUFACTURE OF COLORING MATTER
Year: 1884

page_text: I WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake and Co, Patent
Agents, Southampton Buildings, in the County of Middlesex, do hereby declare the
nature of my invention for "IMPROVEMENTS IN THE MANUFACTURE OF COLORING
MATTER" to be as follows:-
This invention relates to the manufacture of a yellow coloring matter con-
stituted by nitrated disulpho-a-naphthalic acid (l'acide disulfo a naphtolique
mit
The disulpho-a-naphthalic acid (acide disulfo a naphtolique) is prepared by
heating to from 80 to 100 degrees centigrade, during from 8 to 10 hours, a mixture
formed of
30 kilograms of dry and finely pulverized a naphthol ;
180 kilograms of sulphuric acid at 66 degrees Baumé.
The product which is at first pasty becomes liquid towards the end of the
re-action. The mixture is then diluted in 300 kilograms of ice.
The disulpho-a-naphthalic acid (l'acide disulfo-a-naphtolique) mixed with water
is afterwards nitrated by adding gradually 90 kilograms of nitric acid at 40 degrees
Baumé, care being taken not to exceed the temperature of 30 degrees centigrade
during the re-action. Afterwards the temperature is for some moments increased
to about 40 degrees, and then reduced to from 12 to 15 degrees; the mixture is
then filtered and the precipitate pressed with considerable force.
This precipitate is again dissolved in 200 kilograms of boiling water and
filtered, and to the water of filtration containing the yellow coloring matter is
added 500 kilograms of water; the mixture is then saturated by means of
30 kilograms of carbonate of potash at a temperature of from 50 to 60 degrees. It
is then allowed to cool to 15 degrees and filtered, pressed, and dried. The product
thus obtained constitutes the coloring matter.

page_text: OBSERVATIONS.
I may remark that the original feature of this invention consists in employing
sulphuric acid at 66° Baume for the preparation of the disulpho-a-naphthalic acid
(l'acide disulfo a naphtolique) to the exclusion of anhydrous acid, or fuming acid,
which constitutes an improvement upon the processes hitherto known for the
preparation of analogous-acids.

page_text: COMPLETE SPECIFICATION,
I, WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake & Co, Patent
Agents, Southampton Buildings, in the County of Middlesex, do hereby declare
the nature of my invention for "IMPROVEMENTS IN THE MANUFACTURE OF
COLORING MATTER and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
ور
This invention relates to the manufacture of yellow coloring matter constituted
by nitrated disulpho-a-naphtholic acid (l'acide disulfo-a naphtolique nitré.)
The disulpho-a-naphtholic acid (acide disulfo a naphtolique) is prepared by
heating to from 80 to 100 degrees centigrade, during from 8 to 10 hours, a
mixture formed of:-
30 kilograms of dry and finely pulverized a-naphthol ;
180 kilograms of sulphuric acid at 66 degrees Baumé.
The product which is at first pasty becomes liquid towards the end of the
reaction. The mixture is then diluted with 300 kilograms of ice.
The disulpho-a-naphtholic acid (l'acide disulfo-a-naphtolique) mixed with water
is afterwards nitrated by adding gradually 90 kilograms of nitric acid at 40 degrees
Baumé; care being taken not to exceed the temperature of 30 degrees centigrade
during the reaction. Afterwards the temperature is for some moments increased
to about 40 degrees and then reduced to from 12 to 15 degrees; the mixture is then
filtered and the precipitate pressed with considerable force.
This precipitate is again dissolved in 200 kilograms of boiling water and filtered,
and to the water of filtration containing the yellow coloring matter is added
500 kilograms of water; the mixture is then saturated by means of 30 kilograms
of carbonate of potash at a temperature of from 50 to 60 degrees. It is then
allowed to cool to 15 degrees and filtered, pressed and dried. The product thus
obtained constitutes the coloring matter.
I may remark that the original feature of this invention consists in employing
sulphuric acid at 66° Baumé for the preparation of the disulpho-a-naphtholic acid
(l'acide disulfo a naphtolique) to the exclusion of anhydrous acid, or fuming acid,
which constitutes an improvement upon the processes hitherto known for the
preparation of analogous-acids.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
The process hereinbefore described of preparing a yellow coloring matter
(applicable for dyeing textile fibres) by nitrating disulpho-a-naphtholic acid, pre-
pared by causing a reaction upon a-naphthol, in the proportions and under
conditions of temperature as above indicated, by monohydrated sulphuric acid, to
the exclusion of fuming sulphuric acid or sulphuric anhydride.
Deted this and dar of Anil 1885
HASELTINE, LAKE & Co.,
For the Applicant.