The Manufacture or Production of Colouring Matters.
Year: 1897

page_text: Date of Application, 9th Feb., 1897
Complete Specification Left, 1st Nov., 1897-Accepted, 4th Dec., 1897
[Communicated from abroad by THE FARBENFABRIKEN vormals FREDERICH
BAYER & Co. of Elberfeld Germany.]
The Manufacture or Production of Colouring Matters.
I HENRY EDWARD NEWTON of the Office for Patents, 6 Breams Buildings, Chancery
Lane, in the County of London, Patent Agent, do hereby declare the nature of this
invention to be as follows:-
My foreign Correspondents discovered some time since, that sulphuric acid
diazo-derivatives of primary aromatic amines might be readily changed into sulphuric
acids by means of sulphurous acid and copper powder.
The reaction probably took place according to the following equations:-
(I). CH,NN - SOH + H2SO₂ = C₁HNN - SO₂H + H₂SO
CH SO
HSO
diazo sulphite being first formed-from diazo sulphate, then one molecular proportion
of oxygen is taken away therefrom by the action either of sulphurous acid or of
copper, and, at the same time, two molecular proportions of azote are eliminated by
the action of copper.
This invention relates to a method of producing, by means of a similar reaction,
disulpho acids of the so-called Malachite-green series, which constitute very beautiful
blue to greenish-blue dye-stuffs, of great value, by reason of their power of resisting
the action of alkalies and light. They also give even shades when used either alone
or together with other colouring matters.
To effect their object, my foreign Correspondents proceed generally in the
following manner.
They allow alkylated diamido benzhydrols to act on such sulpho acids of the
benzene series which contain the amido group in the meta position to the sulpho
group, and are not substituted in the para position to the amido group. The
hydrols, it is well known, combine in weak acid solutions with the said amido
sulphonic acids, substituting the hydrogen in the para position to the amido group.
On using, for instance, tetramethyldiamido benzhydrol and orthotoluidine para
sulphonic acid, having the formula :-

page_text: My foreign correspondents then proceed to change the free amido group of this
leuco compound into the sulphinic group. By subsequently acting on the sulphinic
acid of the leuco compound thus obtained with oxidizing agents, the sulphinic group 5
is converted into the sulphonic group, and the leuco compound is oxydized. Thus, a
very beautiful greenish-blue colouring matter is obtained, which, in a free state, has
probably the following formula:—

page_text: The parts are by weight.
EXAMPLE.
Tomowing example is given,
43.9 parts of the leuco compound obtained in the well-known manner by the
condensation of tetramethylidiamido benzhydrol with orthotoluidine para sulphonic
acid in a dilute sulphuric acid solution, are dissolved in 500 parts of a 20 per cent
sulphuric acid solution, and diazotized by means of 7 parts of sodium nitrite, keeping
the mixture at a very low temperature. The diazo solution thus obtained being
carefully cooled, is saturated with sulphur dioxide, and treated with copper powder, in
order to form the sulphuric derivative above referred to.
After the reaction is finished, the solution of the sulphinic acid is filtered, and the
filtrate is freed from the sulphurous acid as much as possible; for example, by
allowing air to pass through the liquid. The sulphuric acid is changed into its
calcium salt, and this is subsequently converted into the sodium salt. The sodium
salt, which is obtained in dry state by evaporating its solution, is readily soluble in
hot alcohol, and crystalizes therefrom in a very pure state, forming little colourless,
glittering scales.
53.2 parts of this sodium salt are dissolved in 200 litres (in case the parts are
kilo's by weight) of a 50 per cent acetic acid solution, with the addition of 10 parts
of sulphuric acid, and 180 parts of a 10 per cent manganese dioxide paste and 50
parts of a 20 per cent sulphuric acid are slowly added to the above solution, which is
continuously stirred, the temperature being gradually raised to 50 degrees centigrade.
After some hours, the resulting deep blue solution is neutralized by means of sodium
carbonate, and concentrated by evaporation. The finished dye-stuff, which is
precipitated by the addition of common salt, separates in the form of little scales
having a bronze-like lustre.
My foreign Correspondents do not intend to limit themselves to the particulars
given in this example, which is merely typical, as the directions contained therein
can be varied within certain limits.
Instead of effecting the oxidation of the sulphinic group, and that of the leuco
compound, in one operation, the sulphinic acid group can be first changed into the
sulphonic group, and then, in a separate operation, the thus obtained disulphonic
acid is oxidised to form the dye-stuff. In this case, it is advantageous to carry out
the first operation in an alkaline or neutral solution; for instance, by means of the
calculated quantity of potassium permanganate.
The resulting dye-stuff dyes wool, in acid baths, beautiful greenish-blue shades,
which are fast against the action of alkalies and light.
The process proceeds in an analogous manner, if, instead of tetramethyldiamidobenz-
hydrol, corresponding quantities of other alkylated diamidobenzhydrols are used, or
if, instead of orthotoluidine parasulphonic acid, equivalent proportions of meta-
amido benzene sulphonic acid, or of such substitution products of meta amidobenzene
sulphonic acid, in which the hydrogen in the para position to the amido group is not
substituted, such as ortho-anisidine para-sulphonic acid, orthophenetidine para-
sulphonic acid, chlormeta sulphanilic acid, or amidophenol sulphonic acids, or similar
acids having the above defined constitution, are used.
Doted this Oth 11005
COMPLETE SPECIFICATION.
The Manufacture or Production of Colouring Matters.
I HENRY EDWARD NEWTON of the Office for Patents, 6 Bream's Buildings, Chancery
Lane in the County of London, Patent Agent, do hereby declare the nature of this

page_text: invention and in what manner the same is to be performed, to be particularly
'described and ascertained in and by the following statement:-
In the complete specification filed in respect of the application for Letters Patent
No. 26139, and accepted, I have described a process for changing the amido group
of primary aromatic amines into the sulphinic group.
My foreign correspondents have now found a method of producing, by means of a
similar reaction, disulpho acids of the so-called Malachite green series, which
constitute very beautiful blue to greenish-blue dye-stuffs of great value, by reason of
their power of resisting the action of alkalies and light. They also give even shades
when used either alone or together with other colouring matters.
To effect their object, my foreign correspondents proceed generally in the following
manner :-
They allow alkylated diamodo-benzhydrols to act on such sulpho acids of the
benzene series which contain the amido group in the meta position to the sulpho
group, and are not substituted in the para position to the amido group. The hydrols
it is well known, combine in weak acid solutions with the said amidosulphonic acids,
substituting the hydrogen in the para position to the amido group. On using, for
instance, tetramethyldiamidobenzhydrol and orthotoluidineparasulphonic acid having
the formula

page_text: My foreign Correspondents then proceed to change the free amido-group of this
leuco compound into the sulphinic group. By subsequently acting on the sulphinic
acid of the leuco compound with oxidising agents, the sulphinic group is converted
into the sulphonic group, and the leuco compound is oxidised. Thus, a very beautiful
5 greenish-blue colouring matter is obtained, which has probably the following
formula:-
43.9 parts of the leuco compound, obtained in the well-known manner by the
condensation of tetramethyldiamidobenzhydrol with orthotoluidine para-sulphonic-
acid in a dilute sulphuric acid solution, are dissolved in 500 parts of a 20 per cent
sulphuric acid solution, and diazotised by means of 7 parts of sodium nitrite, keeping
the mixture at a very low temperature. The diazo solution thus obtained being
carefully cooled, is saturated with sulphur dioxide, and treated with 25 parts of
copper powder in the shape of a moist paste, in order to form the sulphinic
derivative above referred to.
After the reaction is finished, the solution of the sulphinic acid is filtered, and the
filtrate is freed from the sulphurous acid as much as possible, for example, by allowing
air to pass through the liquid. The sulphinic acid is changed into its calcium salt, and
this is subsequently converted into the sodium salt. The sodium salt, which is
obtained in a dry state by evaporating its solution, is readily soluble in hot alcohol,
and crystallizes therefrom in a very pure state, forming little colourless glittering
scales.
53-2 parts of this sodium salt are dissolved in 200 litres (in case the parts are kilos
by weight) of a 50 per cent acetic acid solution, with the addition of 10 parts of
sulphuric acid; 180 parts of a 10 per cent manganese dioxide paste, and 50 parts of

page_text: a 20 per cent sulphuric acid are slowly added to the above solution, which is
continuously stirred, the temperature being gradually raised to 50 degrees centigrade.
After some hours, the resulting deep blue solution is neutralised by means of sodium
carbonate, filtered, and concentrated by evaporating. The finished dye-stuff, which
is precipitated by the addition of common salt, separates in the form of little scales
having a bronze-like lustre.
My foreign Correspondents do not intend to limit themselves to the particulars
given in this example, which is merely typical, as the directions contained therein
can be varied within certain limits.
Instead of effecting the oxidation of the sulphinic group and that of the leuco
compound in one operation, the sulphinic acid group can be first changed into the
sulphonic group, and then, by a separate operation, the disulphonic acid thus
obtained is oxidised to form the dye-stuff. In this case, it is advantageous to carry
out the first operation in an alkaline or neutral solution, for instance, by means of
the calculated quantity of potassium permanganate.
The resulting dye-stuff dyes wool in acid baths beautiful greenish-blue even shades,
which are fast against the action of alkalies and light.
The process proceeds in an analogous manner, if, instead of tetramethyldiamido-
benzhydrol, corresponding quantities of other alkylated diamidobenzhydrols (including
the hydrols obtainable from alkylbenzylanilinesulphonic acids) are used; or if, instead
of orthotoluidine parasulphonic acid, equivalent proportions of metaamidobenzene-
sulphonic acid or of such substution products of metaamidobenzenesulphonic acid in
which the hydrogen in the para position to the amido group is not substituted, such
as orthoanisidine parasulphonic acid, orthophenetidine para sulphonic acid,
chlormetasulphanilic acid or similar acids having the above defined constitution,
are used.
Having now particularly described and ascertained the nature of the said invention
and in what manner the same is to be performed (as communicated to me from
abroad), I declare that what I claim is :-
1. The production of sulphonic dye stuffs of the Malachite green series (fast against
the action of alkalies) from the leuco condensation products obtained by condensing,
in equimolecular proportions, alkylated diamido benzhydrols and metamidobenzene-
sulphonic acid, or derivatives thereof, not substituted in the position para to the
amido group, which process consists in transforming the said leuco condensation
products (according to the method described in the Specification of Letters Patent
No. 26139%, or in any other suitable manner) into the corresponding sulphinic
sulphonic leuco compounds, converting the last named products by oxidation into the
corresponding sulphonic carbinol dye-stuffs, and subsequently isolating the latter in
the manner herein before described, or in any other manner yielding the same result.
2. The new products obtainable according to the above claim 1.
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COLL
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