Manufacture of Acid Dyestuffs of the Diphenylnaphthylmethane Series.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Manufacture of Acid Dyestuffs of the Diphenylnaphthylmethane
Series.
I, OLIVER IMRAY, of Birkbeck Bank Chambers, Southampton Buildings, Chancery
Lane, in the County of London, Chartered Patent Agent, do hereby declare the
nature of this invention (as communicated to me from abroad by The Farbwerke '
vormals: Meister Lucius and Brüning, of Hoechst a/Main, in the Empire of Germany,
Chemical Manufacturers,) to be as follows:-
My foreign correspondents have found that from polysulphonic acids of
tetralkyldiamidodiphenylnaphthylmethanes may be obtained valuable green acid dye-
stuffs, which almost completely exhaust the dyefluid; they dye evenly and with-
stand the action of light and soap.
These dyestuffs are produced according to this invention by treating the
tetralkyldiamidodiphenylnaphthylmethanes or their monosulphonic acids, with
energetically acting sulphonating agents and by oxidising the leuco-sulphonic acids
thus obtained.
The production of the leuco-compound and its polysulphonic acid from naphthalene'
and tetralkyldiamidobenzhydrol may be carried out in a single operation.
EXAMPLE.
128 kil. of naphthalene are well mixed with 27.0 kil. of tetramethyldiamido-
benzhydrol and then slowly run into 200 kil. of fuming sulphuric acid con-
taining 20% SO,, the mixture being kept cool with ice. water. The solution thus
obtained is allowed to stand for some time at ordinary temperature or is heated for
several hours to from 50 to 60° C. till a sample of it readily dissolves in water and
dilute ammonia. The product of the reaction is poured into water and treated in
the usual manner to obtain the calcium salt. When tetramethyldiamidodiphenyl-
naphthylmethane-a or ẞ-monosulphonic acid is the material employed the sodium
salt of either of these sulphonic acids is dissolved in five times the quantity of
fuming sulphuric acid containing 20 % SO, and the rest of the process is conducted
in the same manner as before.
The leuco-salt thus obtained is oxidised with the calculated quantity of peroxide
of lead and sulphuric acid into dyestuff. 5 kilos. of this salt for instance, are dis-
solved in 50 litres of water to which is added the calculated quantity of dilute
sulphuric acid and the whole is poured while well stirring into 2.04 kilos. of peroxide
of lead mixed with water, whereupon it is filtered and the dye solution is evaporated
to dryness.
The new dyestuff is in the form of a copper coloured powder, readily soluble in
water with a green colour. A solution of common salt does not precipitate the dye-
stuff; it dyes wool and silk in an acid bath an even green, the tints being fast to
washing and light.

page_text: Instead of tetramethyldiamidobenzhydrol, tetraethyldiamidobenzhydrol and other
alkylated diamidobenzhydrols may be employed.
Tdth: 19th dose of Autober 1902
ABEL & IMRAY,
Agents for the Applicant.

page_text: 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
1. The herein described manufacture of green acid dyestuffs of the diphenyl-
naphthylmethane series by treating tetralkyldiamidodiphenylnaphthylmethanes or
their monosulphonic acids with fuming sulphuric acid or similarly acting agents and
by oxidising the resulting leuco-polysulphonic acids to form dyestuffs.
2. The dyestuffs manufactured as above set forth.