Improvements in the Manufacture of Colouring Matters.
Year: 1897

page_text: [Communicated from abroad by FARBWERK MUHLHEIM VORM A. LEONHARDT & Co.,
of Muhlheim on the Main, in the Empire of Germany.]
☐
Improvements in the Manufacture of Colouring Matters.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent Agents,
45, Southampton Buildings, in the County of Middlesex, do hereby declare the
nature of this invention to be as follows:-
I have shewn in the Specifications of former Letters Patents Nos. 135659⁰
and 1862390 that by acting with nitrosodimethylaniline or analogous compounds
on dimethylmetaamidocresol or analogous compounds, blue basic dyestuffs can
be obtained.
Now I have found that such dyestuffs are also obtained, when instead of the
metaamidocresols condensation products of the latter with aldehydes (especially
formaldehyde) are employed.
For instance, by heating dimethylmetaamidocresol with formaldehyde in an
alkaline watery solution, a condensation product is obtained, which, when
heated with the chlorhydrate of nitrosodimethylaniline in an alcoholic solution,
yields a beautiful blue basic dyestuff.
1191 1 of Dearmshan 1907
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.
=
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Colouring Matters.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent Agents,
45, Southampton Buildings, in the County of Middlesex, 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:-
I have shewn in the Specifications of former Letters Patents Nos. 1356590
and 1862300 that by acting with nitrosodimethylaniline or analogous compounds
on dimethylmetaamidocresol or analogous compounds blue basic dyestuffs can
be obtained.
Now I have found, that such dyestuffs are also obtained, when instead of the
metaamidocresols condensation products of the latter with aldehydes, especially
formaldehyde, are employed.

page_text: For instance, in order to produce a condensation product from formaldehyde
and dimethylmetaamidocresol, 30 kilos. of dimethylmetaamidocresol are dissolved
in 300 litres of water and 24 kilos. of caustic soda lye of 40° Be. and 76 kilos. of
formaldehyde of 40% are added to this solution, which is afterwards heated to
boiling until the smell of formaldehyde has disappeared. The liquid is then
filtered if necessary and neutralized with acetic acid at about 30° C, whereby
the condensation product (the chemical designation of which is tetramethyldiami-
dodioxyditolylmethane) is precipitated. It dissolves easily in dilute mineralic
acids and in caustic alkalies, the solutions being precipitated respectively by
carbonate of soda or acetic acid. By heating the condensation product with
concentrated sulphuric acid a formation of coloring matter will be observed.
In order to produce the blue colouring matters from such condensation product I
proceed for instance as follows:
10 kilos. of the condensation product together with 19 kilos. of the chlorhydrate
of nitrosodimethylaniline and 50 litres of spirit are heated at the reflux cooler,
until the nitrosocompound has disappeared. The mass is then diluted with about
500 litres of hot water, impurities are precipitated by adding acetate of sodium
and the filtered liquid containing the blue dyestuff is mixed with common salt
and chloride of zinc solution. The coloring matter separates first in the form of
a resinous mass of copperlike lustre and afterwards solidifies to green crystals.
In its behaviour towards water, concentrated sulphuric or hydrochloric acid,
caustic soda lye and also in its dyeing properties it proves to be identical with
the corresponding dyestuff produced according to former Letters Patents 1356590
and 1862390.
As I have already stated, the herein described process may be varied; for
instance, nitrosodimethylaniline may be substituted by nitrosodiethylaniline or
by benzol azo-dimethylaniline.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, as communicated to me by
my foreign correspondents, I declare that what I claim is:-
1. The production of blue basic coloring matters substantially as set forth.
2. The blue basic coloring matters produced substantially as hereinbefore
described.
1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.