Manufacture of Blue Dye Stuffy.
Year: 1891

page_text: .
Date of Application, 7th Sept., 1891
Complete Specification Left, 4th June, 1892-4ccepted, 9th July, 1892
PROVISIONAL SPECIFICATION.
Manufacture of Blue Dye Stuffy.
I, JAMES ADAMS HEWITT, of 16 St. Andrews Street, Holborn Circus, in the
County of London, Gentleman, (a communication to me from abroad by Leopold
Cassella & Co., of Frankfort-on-Main, in the Empire of Germany, Manufacturing
Chemists,) do hereby declare the nature of this invention to be as follows:-
This invention relates to the manufacture of blue dye stuffs belonging to the class
of the diamido-triphenylcarbinols, from which hitherto, as it is known only green
or blueish green coloring matters have been obtained. The new dye stuffs are
distinguished by their great intensity, their pure blue shades, and their fastness.
They are derivatives of the secondary orthotoluidine (monomethyltoluidine, mono-
ethyl toluidine). These bases are condensed with meta oxybenzaldehyde, the
resulting products are sulphonated and oxydized.
The following example shows how this invention may be practically executed.
CARPMAEL & Co.,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Manufacture of Blue Dye Stuffs.
I, JAMES ADAMS HEWITT, of 16 St. Andrews Street, Holborn Circus, in the
County of London, Gentleman, (a communication to me from abroad by Leopold
Cassella & Co., of Frankfort-on-Main, in the Empire of Germany, Manufacturing
› Chemists,) 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 relates to the manufacture of blue dye stuffs belonging to the
class of the diamido-triphenylcarbinols, from which hitherto, as it is known only
5 green or blueish green colouring matters have been obtained. The new dye stuff's
ו...

page_text: are distinguished by their great intensity, their pure blue shades, and their fastness.
They are derivatives of the secondary orthotoluidine (monomethyltoluidine, mono-
ethyltoluidine). These bases are condensed with metaoxybenzaldehyde, the
resulting products are sulphonated and oxydized.
The following example shews how this invention may be practically executed.
A
5 kilos of meta oxybenzaldehyde,
is heated during about three days in a boiling water bath. The melt is neutralized
with carbonate of soda and the oil which has not been condensed is distilled off with
steam. The leuco base is filtered, washed and dried. The diethyldiamidoditolyl
oxyphenylmethane is thus obtained in form of a nearly colorless crystalline mass.
It is easily soluble in caustic soda and also in diluted mineral acids. Its melting
point is 153° C. The powdered base is introduced into 60 kilos of strong sulphuric
acid (monohydrate). It is heated to about 100° C. until a sample dissolved in
water shows no longer any precipitate when treated with an excess of acetate of
sodium. When this operation, which generally requires 4 to 6 hours is terminated
the mixture is diluted with water and ice and is neutralized with hydrate of lime.
The leuco sulphonic acid in the filtered solution is oxydised by means of 9.5 kilos
peroxide of lead and 20 kilos of acetic acid. The blue coloring matter will
immediately be formed. The lead is removed by addition of sulphate of soda.
From the filtered solution the coloring matter is precipitated with common salt. It
dyes wool and silk a very pure blue. In the place of peroxides in the foregoing
example other oxidizing agents such as bichromates may be used.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The herein described process of producing coloring matters from monoalkylated
ortho-toluidine by condensing the same with meta-oxy-benzaldehyde, sulphonating
the products thus obtained and oxydising the resulting leuco sulpho acids.
2. As new products of manufacture the coloring matters obtained substantially as
herein before described.
Thith an- of T.. 1900