IMPROVEMENTS IN THE MANUFACTURE OF COLOURING MATTER
Year: 1880

page_text: LETTERS PATENT to Frank Wirth, of the Firm of Wirth and Company, Patent
'Solicitors, at Frankfort on the Main, in the Empire of Germany, for an
Invention of "IMPROVEMENTS IN THE MANUFACTURE OF COLOURING MATTER."
A communication from Eduard Oehler, a person trading under the Firm of
K. Oehler, and resident at Offenbach, in the Empire of Germany.
PROVISIONAL SPECIFICATION left by the said Frank Wirth at the Office
of the Commissioners of Patents on the 14th July 1880.
FRANK WIRTH,. of 'the Firm of Wirth and Company, Patent Solicitors, at
Frankfort on the Main, in the Empire of Germany. "IMPROVEMENTS IN THE
MANUFACTURE OF COLOURING MATTER." [A communication from Eduard Oehler,
a person trading under the Firm of K. Ochler, and resident at Offenbach, in the
Empire of Germany.]
This Invention relates to the production of colouring matter by the application of
the "Lanth"" re-action, that is to say, the action of sulphuretted hydrogen and of
oxidizing bodies on the amido derivatives of secondary aromatic amines.
The process consists of two parts, namely, first, the production of the amido-
derivatives, and, second, the preparation of colours. For preparing the amido-
derivatives different methods may be employed. According to one method any
diazo-compound is combined with a secondary monamine, and the compound is
reduced in any suitable known manner; according to another method. the nitroso
compounds of the secondary monamines are treated with nitric acid, and the
compound produced is reduced in any suitable known manner.
Examples. a. Preparation of Amidoethylamine according to the First Method.―
10 parts sulphanilate of soda are dissolved in 100 parts of water, to which solution
3 parts of sulphuric acid are added, and it is then diazotised with a solution of 44
parts of sodium nitrite in 40 parts of water. On the other hand 75 parts of
ethylaniline are dissolved in 8 parts muriatic acid and 75 parts of water. The cold
solutions are mixed slowly, so that no increase of temperature takes place, and after
standing for some time the separated azoacid is filtered off from the compound. This
azoacid is then reduced by the usual reducing agents, such as iron or tin, with the
addition of muriatic acid.

page_text: b. PREPARATION OF AMIDOETHYLANILINE ACCORDING TO THE SECOND METHOD.
10 parts of ethylaniline, are dissolved in 20 parts muriatic acid and 100 parts
water, and the compound is mixed with a solution of 6 parts sodium nitrite and 30
parts of water. The separated nitroso ethylaniline is allowed to run slowly into
about three times the quantity of nitric acid of 13 specific gravity, under continual
cooling, and after standing for some time the compound is poured into water, and the
separated nitrosonitro body is filtered off. This is then reduced as above. The
production of the colouring matter is effected by treating the above described
amido-derivatives with sulphuretted hydrogen and oxidising bodies, according to
. the known "Lanth" process for the preparation of violet colouring. matter from
nhenvldiemine--
b. PREPARATION OF AMIDOETHYLANILINE ACCORDING TO THE SECOND METHOD.
10 parts of ethylaniline, are dissolved in 20 parts muriatic acid and 100 parts
water, and the compound is mixed with a solution of 6 parts sodium nitrite and 30
parts of water. The separated nitroso ethylaniline is allowed to run slowly into
about three times the quantity of nitric acid of 1.3 specific gravity, under continual
cooling, and after standing for some time the compound is poured into water, and the
separated nitrosonitro body is filtered off. This is then reduced as above. The
production of the colouring matter is effected by treating the above described
amido-derivatives with sulphuretted hydrogen and oxidising bodies, according to
the known "Lanth" process for the preparation of violet colouring matter from
phenyldigmine
Example. PRODUCTION OF A BLUE COLOURING MATTER FROM
AMIDOETHYLANILINE.
A very diluted solution of the nitrate of amidoethylaniline is saturated with
sulphuretted hydrogen, and the saturated solution is treated with chloride of .iron
or other oxidizing bodies until the smell of the sulphuretted hydrogen has
disappeared. The colouring matter produced is then precipitated by the addition
of common salt and a solution of chloride of zinc, and is purified by repeated

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Frank Wirth in the Great Seal Patent Office on the 13th January
1881.
FRANK WIRTH, of the Firm of Wirth and Company, Patent Solicitors, at
Frankfort on the Maine, in the Empire of Germany.
"IMPROVEMENTS IN THE
MANUFACTURE OF COLOURING MATTER." A communication from Eduard Oehler,
a person trading under the Firm of K. Ochler, and resident at Offenbach, in the
Empire of Germany.
This Invention relates to the production of colouring matter by the application of
the "Lauth" re-action, that is to say, the action of sulphuretted hydrogen and of
oxidising bodies on the amido-derivatives of secondary aromatic amines.
The process consists of two parts, namely, first, the production of the amido
derivatives, and, secondly, the preparation of the colours. For preparing the amido-
derivatives different methods may be employed. According to one method any
diazo-compound is combined with a secondary monamine and the compound is
reduced in any suitable known manner; according to another method the nitroso
compounds of the secondary monamines are treated with nitric acid, and the
compound produced is reduced in any suitable known manner.
Examples.-a. Preparation of Amido-ethyl-aniline according to the First
|Method. 10 parts of sulphanilate of soda are dissolved in 100 parts of water, to
which solution 3 parts of sulphuric acid are added, and it is then diazotised with a
solution of 44 parts of sodium nitrite in 40 parts of water. On the other hand 7*5
parts of ethylaniline are dissolved in 8 parts muriatic acid and 75 parts of water.
The cold solutions are mixed slowly so that no increase of temperature takes place,
and after standing for some time the separated azo acid is filtered off from the
compound. This azo acid is then reduced by the usual reducing agents, such as iron
or tin, with the addition of muriatic acid.
b. PREPARATION OF AMIDO-ETHYL-ANILINE ACCORDING TO THE SECOND METHOD.
.
10 parts of ethylaniline are dissolved in 20 parts muriatic acid and 100 parts
water, and the compound is mixed with a solution of 6 parts sodium nitrite and
30 parts of water. The separated nitroso-ethyl-aniline is allowed to run slowly into
about three times the quantity of nitric acid of 1.3 specific gravity under continual
cooling, and after standing for some time the compound is poured into water, and
the separated nitrosonitro body is filtered off. This is then reduced as above. The
production of the colouring matter is effected by treating the above described
amido-derivatives with sulphuretted hydrogen and oxidising bodies, according to
the known "Lauth" process for the preparation of a violet colouring matter from
phenylenediamine.
Example. Production of a Blue Colouring Matter from Amido-ethyl-aniline.―
A very dilute solution of the nitrate of amido ethyl-aniline is saturated with
sulphuretted hydrogen, and the saturated solution is treated with chloride of iron
or other oxidising bodies until the smell of the sulphuretted hydrogen has
disappeared. The colouring matter produced is then precipitated by the addition
of common salt and a solution of chloride of zinc, and is purified by repeated
solution.
Having thus described the nature of this Invention, and in what manner the
same is to be performed, as communicated to me by my correspondent, I claim,-
First. The production of amido-derivatives of the secondary aromatic monamines
by means of the processes herein described.

page_text: Second. The production of colouring matters from the amido derivatives of the
secondary aromatic monamines by the action of sulphuretted hydrogen and of
oxidising bodies, substantially as herein described.
. In witness whereof, I, the said Frank Wirth, have hereunto set my hand
and seal, this Tenth day of January, in the year of our Lord One thousand
eight hundred and eighty one.
FRANK WIRTH. (L.S.).