Manufacture of a New Rhodamine Dyestuff.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Manufacture of a New Rhodamine Dyestuff.
1, OLIVER IMRAY, of Birkbeck Bank Chambers, Southampton Buildings,
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 & Brüning, of Hoechst a/Main, in the Empire of Germany,
Chemical Manufacturers,) to be as follows:-
My foreign correspondents have found that by the action of monoethylamine
upon dichlorofluoresceine chloride (derivative of dichlorophthalic acid) and by the
subsequent sulphonation of the dichlorodiethylrhodamine, thus formed, a new
valuable dyestuff may be obtained.
The manufacture of the symmetrical dichlorodiethylrhodamine is illustrated by
the following example.
EXAMPLE.
45 kilos. of the hydrochloride of monoethylamine, 36 kilos. of chloride of zinc,
60 kilos. of dichlorofluoresceine chloride and 36 kilos. of quick-lime (or the
equivalent quantity of another appropriate base) are heated to 200° C. The mass
begins to melt gradually, assuming a dark-red colour and finally a metallic lustre.
It is heated while being stirred till the bubbles cease and the mass becomes
refractory; it is then pulverised and boiled several times, hydrochloric acid being
added. The dichlorodiethylrhodamine remains undissolved; it is filtered and
dried.
It forms a bright red powder, insoluble in water, sparingly soluble in hot
hydrochloric acid which is not too dilute, with a red yellow colour. This solution
becomes bluish pink on dilution with water, when part of the dyestuff separates
as bluish red flakes; in concentrated sulphuric acid it dissolves with a light yellow
colour, which on addition of water becomes first red-yellow, then bluish-pink and
Alcohol dissolves it with a
finally the dyestuff is precipitated in red flakes.
vivid yellow-red colour and strong green fluorescence, which disappears on addition
of alkali. The product dyes silk a beautiful bluish-red.
To transform this dyestuff which is insoluble in water to one soluble in water,
o it is treated with sulphonating agents as illustrated by the following example:--
25 kilos. of the dyestuff are dissolved in 150 kilos. of monohydrated sulphuric
acid at about 40° C. to which are slowly and carefully added, so as not to exceed
the temperature of 35 to 40° C., 150 kilos. of fuming sulphuric acid of 20 per
cent. strength. The whole is stirred for about 3 hours, till a sample of it easily
5 dissolves in sodium carbonate; it is then poured into cold water, the precipitated
sulphonic acid is filtered off, dissolved in sodium carbonate and the filtered
solution of sodium salt is evaporated to dryness. The dyestuff, thus obtained, is
a dark red mass of metallic lustre and when pulverised forms a dark red powder.
It is easily soluble in water with a beautiful red colour and green fluorescence,
o and from this solution mineral acids separate the free sulphonic acid in blue-red

page_text: flakes. Concentrated sulphuric acid dissolves the dyestuff with a light yellow
colour, which on addition of water becomes yellow-red and finally bluish pink.
The sulphonated dichlorodiethylrhodamine dyes wool very pure and vivid
bluish-red tints.
ABEL & IMRA 1,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Manufacture of a New Rhodamine Dyestuff.
I, OLIVER IMRAY, of Birkbeck Bank Chambers, Southampton Buildings,
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 & Brüning, of Hoechst a/Main, in the Empire of Germany,
Chemical Manufacturers), and in what manner the same is to be performed, io
be particularly described and ascertained in and by the following statement:-
My foreign correspondents have found that a new valuable dyestuff may be
obtained, by sulphonating dichlorodiethylrhodamine, the manufacture of which
is described in the Specification No. 9600 of 1888.
To transform this product which is insoluble in water to one soluble in water,
it is according to the present invention treated with sulphonating agents as illus-
trated by the following example.
25 kilos. of the dyestuff are dissolved in 150 kilos. of monohydrated sulphuric
acid at about 40° C. to which are slowly and carefully added, so as not to exceed
the temperature of 35 to 40° C., 150 kilos. of fuming sulphuric acid of 20 per
cent. strength. The whole is stirred for about 3 hours, till a sample of it easily
dissolves in sodium carbonate; it is then poured into cold water, the precipitated
sulphonic acid is filtered off, dissolved in sodium carbonate and the filtered
solution of sodium salt is evaporated to dryness. The dyestuff, thus obtained, is
a dark red mass of metallic lustre and when pulverised forms a dark red powder.
It is easily soluble in water with a beautiful red colour and green fluorescence;
and from this solution mineral acids separate the free sulphonic acid in blue-red
flakes.
Concentrated sulphuric acid dissolves the dyestuff with a light yellow colour,
which on addition of water becomes yellow-red and finally bluish pink.
The sulphonated dichlorodiethylrhodamine dyes wool very pure and vivid
bluish-red tints.
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 a readily soluble rhodamine dyestuff,
by treating with sulphonating agents, symmetrical dichlorodiethylrhodamine, a
derivative of dichlorophthalic acid.
2. The dyestuff manufactured as above set forth.