Year: 1887

page_text: Date of Application, 13th June, 1887
Complete Left, 12th Mar., 1888
Complete Accepted, 20th Apr., 1888
I CARL AUGUST BENNERT of Hebburn on Tyne in the County of Durham
Chemist do hereby declare the nature of this invention to be as follows:-
This Invention has for its object, improvements in the manufacture of colouring
matters by reactions between certain Hydrazine compounds of the aromatic series and
Nitrotartaric acid obtained by action of Nitric acid upon Tartaric acid as discovered
and described by Dessaignes (Comptes rendus hebdomadaires des séances de l'académie
des sciences Paris Vol. XXXIV. p. 731 sequ).
The solution of this acid in water when heated to about 70° Centigrade with
addition of any of the said Hydrazine compounds reacts upon them and colouring
matters suitable for dyeing and printing are formed. The colouring matter which is
obtained by thus operating with Phenylhydrazine-para-sulpho-acid is of a yellow
colour and forms a sodium salt which is easily soluble in water.
The prejudicial effect upon the Hydrazine-compounds of the nitrous gases which
are formed as bye-products may be lessened by the judicious addition of a reducing
reagent such for instance as a stream of Sulphuretted Hydrogen.

page_text: COMPLETE SPECIFICATION.
Improvements in the Manufacture of Colouring Matters.
I CARL AUGUST BENNERT of Hebburn on Tyne in the County of Durham Chemist
do hereby declare the nature of this Invention and in what manner the same is to
be performed to be particularly described and ascertained in and by the following
statement:-
This Invention has for its object improvements in the manufacture of colouring
matters by reactions between certain hydrazine compounds of the aromatic series
(videlicit Phenylhydrazine, Tolylhydrazine Alpha-Naphtylhydrazine or their sulpho-
acids) and Nitrotartaric acid obtained by the action of nitric acid upon tartaric acid
as discovered and described by Dessaignes (Comptes rendus hebdomadaires des séances
de l'académie des sciences, Paris vol. XXXIV p. 731 et sequ).
The solution of this acid in water when heated to about 70° centigrade with the
addition of any of the aforesaid hydrazine compounds reacts upon them and colouring
matters suitable for dyeing and printing are formed.
The colouring matter which is obtained by thus operating with Phenylhydrazine-
para-sulpho-acid is of a yellow colour and forms a sodium salt which is easily soluble
in water.
The prejudicial effect upon the hydrazine compounds of the nitrous gases which are
formed as bye-products may be lessened by the judicious addition of a reducing
reagent such for instance as a stream of sulphuretted hydrogen.
I give the following example of the manner in which my Invention may be carried
into effect but I do not limit myself to the precise proportions and details of this
example.
-Eight parts by weight of Nitrotartaric acid are dissolved in ten parts by weight
of ice water and mixed with a fine emulsion of 12.5 parts by weight of Phenylhydrazine
para-sulpho-acid dissolved in 30 parts by weight of water to which are added
0.5 parts by weight of concentrated sulphuric acid and the mixture is heated on a
steam bath.
As soon as the solution begins to turn Yellow a current of Sulphuretted Hydrogen
is passed through it. It is to be observed that as much of the nitrous gases as
possible must be destroyed but that likewise an excess of Sulphuretted hydrogen must
be avoided.
After some time the reaction is finished.
When the solution has become cold it is filtered from the Phenylhydrazine-para-
sulpho-acid not reacted upon, neutralized with soda and the color precipitated and
treated as usual in such cases.

page_text: Similar results are obtained by the use of Phenyl-hydrazine Tolyl-bydrazine and
Alpha Naphtyl hydrazine or of their sulpho acids.
Having now particularly described and ascertained the nature of this Inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
The manufacture or production of the colouring matters herein before referred to by
causing Nitro-tartaric acid to act upon Phenylhydrazine Tolylhydrazine Alpha-
Naphtylhydrazine or upon their sulpho-acids.