Improvements relating to Colouring Matters.
Year: 1889

page_text: Date of Application, 11th Nov., 1889
Complete Specification Left, 21st July, 1890-Accepted, 23rd Aug., 1890
PROVISIONAL SPECIFICATION.
[Communicated from abroad by Messrs. WIRTH & Co., of Frankfort-on-the-Main,
in the Empire of Germany, acting as Agents of A. Leonhardt & Co., of Mühlheim,
near Frankfort-on-the-Main, in the Empire of Germany.]
Improvements relating to Colouring Matters.
I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co., Patent Agents,
Southampton Buildings in the County of Middlesex, do hereby declare the nature
of this invention to be as follows :-
Formaldehyde (CH₂O) when combined with metadiamines of the aromatic series,
especially in presence of a mineral acid, forms derivatives of diphenylmethane, which
in some cases crystallize out of the solution in a pure state.
These derivatives of diphenylmethane when treated with agents capable of
eliminating ammonia from the molecule (such as hydrochloric acid at a high
temperature) are transformed into leuco-derivatives of acridine, which can be
oxydized to form a new yellow colouring matter, capable of dyeing wool, silk or
mordanted cotton a beautiful yellow and which is capable of resisting washing with
sonp better than the so-called benzoflavines.
Instead of formaldehyde, certain other aldehydes of the fatty series can be
employed.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements relating to Colouring Matters.
I, HENRY HARRIS LAKE of the firmn 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:—
It is known that from benzaldehyde and metaphenylendiamine or metatoluyl-
endiamine, tetraamido-derivatives of triphenylmethan can be obtained which by
elimination of ammonia and subsequent oxidation can be transformed into colouring
matters derived from phenylacridine, the so-called benzoflavines.
Now I have found that formaldehyde (which has not generally been known as an
equivalent of benzaldehyde) when brought into reaction with metatoluylendiamine in
a suitable way, yields very easily a tetraamido-derivative of diphenylmethan which by
elimination of ammonia and subsequent oxidation yields a beautiful new yellow dye-
stuff derived from acridine.
This new dyestuff dissolves more easily in water and, when dyed on mordanted
cotton is faster against soap than the benzoflavines. Its aqueous or alcoholic solution,
as well as silk dyed with it, shows a magnificent green fluorescence.
The following is a description of the manner in which this invention may be carried

page_text: After a short time, the sulphate of the product of condensation crystallizes out of
the solution and is gathered on a filter.
If pure materials have been employed the yield of the product of condensation is
nearly equal to that obtained by theory.
The condensation can also be carried out in spirit or methylic alcohol, but I have
not found much advantage in employing other solvents than water.
100 tres " water,
in an enamelled autoclave for about 6 hours up to 150-160° Cent.
After cooling down and opening the vessel, the brownish red liquid containing the
leuco compound of the dyestuff is filtered (if necessary) and mixed with about
10 litres of a solution of sesquichloride of iron of 1.4 specific gravity, and the whole
mass is then gradually heated up to say, 90° Cent. The colouring matter separates
in the form of a yellow crystalline powder and is filtered and well washed with dilute
hydrochloric acid or saltwater.
Instead of hydrochloric acid, other suitable acids capable of eliminating ammonia,
such as diluted sulphuric acid, can be used for the transformation of the above
mentioned tetramidoditolylmethan, into the leuco compound. Further, this leuco
compound can be oxidized with other suitable oxidizing agents; thus for instance
when the solution containing the leuco compound is allowed to stand in the open air,
the dyestuff gradually separates from the fluid.
Having now particularly described and ascertained the nature of the 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 :-
First. The production of tetramidoditolylmethan by treating metatoluylenediamine
with formaldehyde substantially as hereinbefore described.
Second. Tetramidoditolylmethan obtained by treating metatoluylenediamine with
formaldehyde, substantially as herein before described.
Third. The production of a new yellow dyestuff by heating tetramidoditolylmethan
with bodies capable of eliminating ammonia and oxidizing the obtained leuco compound,
substantially as hereinbefore described.
Fourth. A new yellow dyestuff obtained by heating tetramidoditolylmethan with
bodies capable of eliminating ammonia and oxidizing the obtained leuco compound,
substantially as herein before described.
Dated this 21st day of July 1890.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.