An Improved Manufacture of Colouring Matter.
Year: 1889

page_text: Date of Application, 30th Oct.. 1889
Complete Specification Left, 25th July, 1890-Accepted, 30th Aug., 1890.
'
PROVISIONAL SPECIFICATION.
[Communicated from abroad by Messrs. WIRTH & Co., of Frankfort-on-the-Main
acting as Agents of A. Leonhardt & Co., of Mühlheim near Frankfort-on-the-Main,
both in the Empire of Germany.]
•
An Improved Manufacture of Colouring Matter.
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:
We have found that the dioxynaphtaline obtained from naphtalinedisulpho acid
forms a nitroso compound which is capable of forming coloured lacks if brought into
connection with metallic oxides which makes it useful for dyeing and printing of
mordanted fibres.
Thus there are obtained green tints with iron and brown tints with chrome mordants
which are quite fast.
The production of this nitroso compound is carried out in the manner, generally
applied for the production of nitrosophenols by gradual addition of an aqueous solution
of nitrit into an acidulated cold aqueous solution of dioxynaphtaline, whereupon the
red precipitate is filtered off and well washed out.
Dated this 30th day of October 1889.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
An Improved Manufacture of Colouring Matter.
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:-
a
I have found that dioxynaphthalene of the melting point 186° C. obtained from
naphthalenedisulpho acid or ẞ naphtholmonosulpho acid F. by melting with caustic
alkali, reacts with nitrous acid forming in all circumstances a well defined mononitroso-
compound.
The method according to which I carry out this nitrosation, is generally the same
as that employed for analogous purposes. The most simple method is as follows.
I take a solution of 1 kilo. of dioxynaphthalene in 200 litres of water acidulated
with 3 kilos. of concentrated sulphuric acid and add to this solution in the cold state a
solution of about 0.4 kilos. of nitrite of sodium in 10 litres of water, until a filtered
sample gives no further red precipitate with nitrite of sodium. The red precipitate
is then filtered and well washed with cold water and employed best in the form
of a paste.
0
Instead of sulphuric acid, other suitable acids, as for instance, hydrochloric acid or
acetic acid can be used.
When an alcoholić solution of the said dioxynaphthalene is treated in the cold, with
a solution of ethylnitrite in spirit, the fluid takes a reddish-brown colour and the
nitroso-derivative separates from the solution.
The mononitroso-dioxynaphthalene obtained forms a brown powder which dissolves
in a solution of carbonate of soda with a dark red colour and can be precipitated by
means of acetic acid. The solution of the said nitroso-derivative in concentrated"

page_text: sulphuric acid is intensely green, and when poured into much water yields a brown
precipitate.
The said mononitroso-compound is capable of forming coloured lacks with metallic
oxides which makes it useful for the dyeing of mordanted wool. Thus if I boil wool
with 10% of copperas and 5% of tartar and then dye with the above mononitroso-
dioxynaphthalene I obtain very pure olive green shades which are very fast against
light and fulling. The chromium mordants give brown shades which have not proved
to be as fast as the green shades above mentioned.
For dyeing or printing on mordanted cotton the said mononitroso-dioxynaphthalene
is of little or no value.
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 herein described process of producing a mononitroso-dioxynaphthalene
which process consists in nitrosating dioxynaphthalene of the melting point 186° C:
substantially as described.
Second. The mononitroso-dioxynaphthalene obtained by nitrosating dioxynaphthalene
of the melting point 186° C. substantially as herein before described.
Third. The employment of the mononitroso-dioxynaphthalene mentioned under
claim 2 for the purpose of dyeing iron-mordanted wool in green shades.
Dated this 25th day of July 1890.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.