The Manufacture and Production of New Nitrosamine Compounds, suited for Use in the Preparation of Diazo Compounds, and of Azo Dyes.
Year: 1895

page_text: Date of Application, 12th July, 1895
Complete Specification Left, 20th Feb., 1896-Accepted, 21st Mar., 1896
PROVISIONAL SPECIFICATION.
The Manufacture and Production of New Nitrosamine Compounds,
suited for Use in the Preparation of Diazo Compounds, and of
Azo Dyes.
I JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of London
Gentleman do hereby declare the nature of this invention (which has been
communicated to me from abroad by The Badische Anilin and Soda Fabrik
of Ludwigshafen on Rhine in the Empire of Germany) to be as follows:-
This invention relates to a further development of the inventions described in
the Specifications of Letters Patent No. 20605 of 1893 and No. 3397 of 1894
granted to me on communications from my present foreign correspondents.
In the latter of these Specifications the conversion of diazo-compounds derived
from such aromatic amido-compounds as contain no substituting acid-group or
groups into new nitrosamines and the useful application of these bodies are
described. The process consists in heating the respective diazo compound with
solutions of caustic alkalies until a test dissolved in water and mixed with an
alkaline solution of beta-naphthol does not yield azo-dye.
My foreign correspondents have now found that this process can also be applied
to diazo-azo-compounds such as are derived from amido-azo-benzol and its
homologues or benzol-azo-alpha-naphthylamine.
With reference to amido-azo-benzol a conversion into a nitrosamine has already
been described viz. in the French Patents No. 234029 of the 5th February 1894
and No. 238688 of the 22nd May 1894.
This process however has not led to practical results as is seen from the following.
By treating for instance a five per cent. solution of the diazo-compound of amido-
azo-benzol with a ten per cent. soda lye at a temperature of fifty degrees Centigrade
as described in the said French Patent No. 234,029 and cooling down a substance
crystallizes out in golden-yellow great leaves which has been considered up to now
as the pure nitrosamine sodium salt of the amido azo benzol, because when mixed
with a solution of beta-naphthol in a strong excess of caustic alkali no formation
of an azo-dye is observed.
My foreign correspondents have however discovered that this test is not reliable
since the presence of a strong excess of the caustic alkali prevents the formation of
azo-dye even from the normal diazo-compound and that the above named well
crystallizing product consists only in its smaller part of the sodium salt of the
nitrosamine and in its greater part of the sodium salt of the unchanged diazo-
compound of the amido-azo-benzol. My foreign correspondents have discovered
that a complete conversion of the diazo compound into the nitrosamine is best
effected by heating the former with a stronger alkali lye and at a higher
temperature.
The following example will serve to further illustrate the invention but it is
capable of variation without departure from the nature of the invention and I do
not bind myself thereto. The parts are by weight.

page_text: To the thin mixture thus obtained add while stirring and cooling three parts of
powdered caustic soda at a temperature of about plus ten degrees Centigrade.
Then heat, while stirring continuously, until a test of the melt dissolved in water
and admixed to a weakly alkaline solution of beta-naphthol no longer yields any
dyestuff. This point will be reached at a temperature of about one hundred and
thirty to one hundred and fifty degrees Centigrade.
The sodium salt of the nitrosamine thus produced forms a layer on the melted
caustic soda which can be mechanically separated therefrom. It can be purified
by further crystallizing from water.
Instead of adding the alkali in two different portions the whole quantity of it
may be added at the beginning. In this case it is preferable to apply the more
soluble caustic potash instead of caustic soda and to work as follows:-
Run one part of the said diazo-solution or paste while stirring and cooling into
eight parts of a seventy-five per cent. caustic potash-lye. Then heat as above
described until by the test given no more dyestuff is yielded.
In this example the amido-azo-benzol may be replaced by its homologues or by
benzol-azo-alpha-naphthylamine.
Dated this 19th do of T... 100-
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.
COMPLETE SPECIFICATION.
The Manufacture and Production of New Nitrosamine Compounds,
suited for Use in the Preparation of Diazo Compounds, and of
Azo Dyes.
I JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of London
Gentleman do hereby declare the nature of this invention (which has been
communicated to me from abroad by The Badische Anilin & Soda Fabrik of
Ludwigshafen on Rhine in the Empire of Germany) 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 a further development of the inventions described in
the Specifications of Letters Patent No. 20605 of 1893 and No. 3397 of 1894
granted to me on communications from my present foreign correspondents.
In the latter of these Specifications the conversion of diazo-compounds derived
from such aromatic amido-compounds as contain no substituting acid-group, or
groups, into new nitrosamines and the useful application of these bodies are
described. The process consists in heating the respective diazo-compounds with a
solution of a caustic alkali until a test portion dissolved in water, and mixed with
an alkaline solution of beta-naphthol, does not yield azo-dye.
My foreign correspondents have now found that this process can also be applied
to diazo-azo-compounds such as are derived from amido-azo-benzol and its
homologues, or benzol-azo-alpha-naphthylamine.
With reference to amido-azo-benzol a conversion into a nitrosamine has already
been described viz. :-in the Specifications of French Patents No. 234029 of the
5th February 1894 and No. 238688 of the 22nd May 1894.
This process however has not led to practical results as is seen from the
following-By treating for instance a five per cent. solution of the diazo-compound
of amido-azo-benzol with a ten per cent. soda lye, at a temperature of fifty degrees
Centigrade, as described in the Specification of the said French Patent No. 234029,
and cooling down a substance crystallizes out in golden-yellow leaf-like crystals
which has been considered up to now as the pure nitrosamine sodium-salt of the

page_text: amido-azo-benzol, because when mixed with a solution of beta-naphthol in a strong
excess of caustic alkali no formation of an azo-dye is observed.
My foreign correspondents have however discovered that this test is not reliable,
as indicating the complete formation of nitrosanine compound-since the presence
of a strong excess of the caustic alkali in this case prevents the formation of azo-
dye even from the normal diazo-compound. They have further found that the
above named well crystallizing product cousists only to a small extent of the
sodium-salt of the nitrosamine but in its greater part is the sodium-salt of
the unchanged diazo-compound of the amido-azo-benzol.
My foreign correspondents have discovered that a complete conversion of the
diazo-compound into the nitrosamine is best effected by heating the former with a.
stronger alkali-lye and at a higher temperature.
The following example will serve to further illustrate the invention and the
manner in which it can be carried into practical effect but it is capable of variation
without departure from the nature of the invention and I do not bind myself
thereto. The parts are by weight.
Run one part of a fifteen per cent. solution or paste of diazo-azo-benzol-chloride.
into two parts of caustic soda-lye of 40° Bé. at a temperature lower than about plus.
five degrees Centigrade.
To the thin mixture thus obtained add while stirring and cooling three parts of
powdered caustic soda at a temperature of about plus ten degrees Centigrade.
Then heat while stirring continuously, until no dyestuff is yielded on dissolving a
test portion of the melt in water and mixing with it a solution of beta-naphthol in.
such a way that the whole is but slightly alkaline. This point will be reached at a
temperature of about one hundred and thirty to one hundred and fifty degrees.
Centigrade.
The sodium salt of the nitrosamine thus produced forms a layer on the melted
caustic soda which can be mechanically separated therefrom. It can be purified.
by further crystallizing from water.
Instead of adding the alkali in two different portions the whole quantity of it
may be added at the beginning. In this case it is preferable to employ caustic
potash instead of caustic soda, as the former is more soluble, aud to work as
follows:-
Run one part of the aforesaid diazo-solution or paste, (while stirring and cooling).
into eight parts of a seventy-five per cent. caustic potash-lye. Then heat as above
described until by the test hereinbefore given no more dyestuff is yielded.
In this example the amido-azo-benzol may be replaced by its homologues or by
benzol-azo-alpha-naphthylamine.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. The manufacture of nitrosamine compounds by treating the diazo-azo-
compounds hereinbefore set forth, with strong caustic alkali at a high temperature
substantially as hereinbefore described.
2. As new articles of manufacture. the new nitrosamine compounds such as can.
be obtained substantially as herein before described.
Dated this 20th day of February 1896.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.