Process for Rendering Nitroso-bases Stable.
Year: 1899

page_text: Process for Rendering Nitroso-bases Stable.
I, OLIVER IMRAY, of Birkbeck Bank Chambers, Southampton Buildings, in the
County of London, Chartered Patent Agent, do hereby declare the nature of
this invention (as communicated to me from abroad by The Farbwerke vormals:
Meister Lucius and Brüning, of Hoechst /Main, in the Empire of Germany,
Chemical Manufacturers) to be as follows 1-
1-
When employing nitroso-bases as described in the German Patent No. 103921,
it has hitherto been difficult to produce them in a sufficiently stable form, so as
not only to stand a long journey without danger, but also to keep within certain
limits of temperature. The transport of nitroso-bases in form of aqueous pastes,
for instance, was impracticable, as they decomposed on standing for some time
at ordinary temperature and became dark in colour. On dissolving them in
hydrochloric acid, an insoluble resin remains behind and the shades, obtained
with naphthol, resorcinol, dioxynaphthalene etc., are much weaker and duller
than those obtained with a freshly prepared base.
My foreign correspondents have therefore, tried to introduce the nitroso-bases
on the market in a dry state and the result has been that they are thoroughly,
stable in this form for months and even a year. In some isolated cases, how-
ever, the nitroso-bases thus dried, after having been stable for months, became..
suddenly decomposed for some reason not yet explained. This decomposition
which took place in several cases in a harmless manner, leaving behind a black
resin, occurred. in other cases with an appearance of fire and sudden explosion
of the whole material so that the use of nitroso-bases had to be considered as
dangerous. There was some reason to believe this decomposition to have been
caused by a formation of nitroso-phenol brought about by traces of free alkali,
for it was proved, that a mixture of nitroso-bases with some nitroso-phenol
exploded much more easily and powerfully when heated, than was the case with
a pure nitroso-base. On the other hand, however, this supposition was con-
troverted by the circumstance, that a nitroso-base to which traces of an acid
had been added purposely, decomposed in the same violent manner as the bases
precipitated with the calculated quantity or excess of alkali.
My correspondents have found that it is possible to obtain the nitroso-bases
in form of thoroughly stable pastes, if a certain percentage of sodium carbonate
or other alkali carbonate or a salt of weak alkaline reaction be added.
This observation was all the more surprising as the nitroso-bases are easily
decomposed by alkalies into nitroso-phenol and dialkylamine, whereas in fact
the stability of the nitroso-pastes was increased accordingly as the percentage of
those salts was increased.
Whilst the pastes made up only with water decompose at ordinary tempera-
ture after a short time, the nitroso-bases in form of soda-alkaline paste may
be heated to a higher temperature without visible decomposition or decrease of
intensity in colour.
EXAMPLE.
The precinitated pressed and washed base from 310.8 kilos of the hydro-

page_text: amounts to 487.5 kilos. Then 12.5 kilos of soda-ash are introduced and by con-
tinued stirring a uniform mass is obtained.
As additions may be used, besides carbonates and bicarbonates of alkalies,
which are preferabe, other bodies of weak alkaline reaction, such as sodium
acetate or phosphate.
Dated this 8th day of August 1800
ABEL & IMRAY,
Agents for the Applicant.
i
Process for Rendering Nitroso-bases Stable.
I, OLIVER IMRAY, of Birkbeck Bank Chambers, Southampton Buildings, in the
County of London, Chartered Patent Agent, do hereby declare the nature of
this invention (as communicated to me from abroad by The Farbwerke vormals:
Meister Lucius and Brüning, of Hoechst /Main, in the Empire of Germany,
Chemical Manufacturers) and in what manner the same is to be performed to
be particularly described and ascertained in and by the following statement:—
When employing nitroso-bases as described in the German Patent No. 103921,
it has hitherto been difficult to produce them in a sufficiently stable form, so as
not only to stand a long journey without danger, but also to keep within certain
limits of temperature. The transport of nitroso-bases in form of aqueous pastes,
for instance, was impracticable, as they decomposed on standing for some time
at ordinary temperature and became dark in colour. On dissolving them in
hydrochloric acid, an insoluble resin remains behind and the shades, obtained
with naphthol, resorcinol, dioxynaphthalene etc., are much weaker and duller
than those obtained with a freshly prepared base.
My foreign correspondents have therefore, tried to introduce the nitroso-bases
on the market in a dry state and the result has been that they are thoroughly
stable in this form for months and even a year. In some isolated cases, how-
ever, the nitroso-bases thus dried, after having been stable for months, became
suddenly decomposed for some reason not yet explained. This decomposition
which took place in several cases in a harmless manner, leaving behind a black
resin occurred in other cases with an ignition and sudden explosion
of the whole material so that the use of nitroso-bases had to be considered as
dangerous. There was some reason to believe this decomposition to have been
caused by a formation of nitroso-phenol brought about by traces of free alkali,
for it was proved, that a mixture of nitroso-bases with some nitroso-phenol
exploded much more easily and powerfully when heated, than was the case with
a pure nitroso-base. On the other hand, however, this supposition was con-
troverted by the circumstance, that a nitroso-base to which traces of an acid
had been added purposely, decomposed in the same violent manner as the bases
precipitated with the calculated quantity or excess of alkali.
My correspondents have found that it is possible to obtain the nitroso-bases
in form of thoroughly stable pastes, if a certain percentage of sodium carbonate
or other alkali carbonate or a salt of feeble alkaline reaction be added.
This observation was all the more surprising as the nitroso-bases are easily
decomposed by alkalies into nitroso-phenol and dialkylamine whereas in fact
the stability of the nitroso-pastes was increased accordingly as the percentage of
those salts was increased.
Whilst the pastes made up only with water decompose at ordinary tempera-
ture after a short time, the nitroso-bases in form of soda-alkaline paste may
be heated to a higher temperature without visible decomposition or decrease of
intensity in colour.

page_text: EXAMPLE.
The precipitated, pressed and washed base from 310.8 kilos of the hydro-
chloride of nitroso-dimethylaniline is mixed with so much water that the mass
amounts to 487.5 kilos. Then 12.5 kilos of soda-ash are introduced and by con-
tinued stirring a uniform mass is obtained.
As additions may be used, instead of carbonates and bicarbonates of alkalies,
which are preferable other bodies of feeble alkaline reaction, such as sodium
acetate or phosphate.
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:-
Process for rendering stable nitroso-bases of the type of nitroso- mono- or
dimethylaniline by adding salts of alkaline reaction, such as carbonates, or other
substances capable of reacting with acids, to the bases made up into pastes with
water, substantially as described.
ABEL & IMRAY,
Agents for the Applicant.