Manufacture of New Leuco-bases of the Triphenylmethane Series and of Colouring Matters derived therefrom.
Year: 1899

page_text: Date of Application, 28th Apr., 1899
Complete Specification Left, 15th Jan., 1900-Accepted, 17th Feh., 1900
Manufacture of New Leuco-bases of the Triphenylmethane Series and
of Colouring Matters derived therefrom.
I, CHARLES DENTON ABEL, of Birkbeck Bank Chambers, Southampton Buildings,
in the County of London, Consulting Engineer and Chartered Patent Agent,
do hereby declare the nature of this invention (as communicated to me from
abroad by The Actien-Gesellschaft für Anilin Fabrikation, of Berlin, in the
Empire of Germany, Chemical Manufacturers) to be as follows:-
It has been found by A. Kern that derivatives of triphenylmethane can be
obtained by condensing tetra-alkyl-diamidobenzhydrol with amido compounds,
(compare German Patent [expired] No. 27,032.) According to all observations
hitherto published these condensations unexceptionally take place in such manner
that the CH group of the hydrol enters into para-position to the amido-group if
this position is free (compare Nölting, Berichte der deutschen chemischen
Gesellschaft XXII, page 554). Only para-substituted amines have been observed
to yield condensation products which contain the CH group in a different
position.
My foreign correspondents have now made the unexpected discovery that
certain amines with free para-position, such, for instance as ortho-toluidine and
its alkyl-derivatives vield quite different condensation products with hydrols,
if strong sulphuric acid is used as a condensing agent.
The leuco-bases thus obtained are essentially different from those heretofore
prepared from the same components.
For instance, by condensing benzyl-ortho-toluidine with tetramethyldiamido-
benzhydrol in solution in monohydrate sulphuric acid, a new leuco-base is
formed which yields, when treated with oxidising agents, a green dyestuff, whereas
according to the German Patent No. 96230, only violet colouring matters can be
obtained from the same components by the condensation methods hitherto
employed.
The following examples may serve to illustrate this invention.
1. 27 kilos. of tetramethyldiamidobenzhydrol are dissolved in 160 kilos. of
monohydrate sulphuric acid and the solution thus obtained is introduced into
11 kilos of ortho-toluidine. The mass is then heated to 50° C. for about 12 hours
The
whereupon it is thrown on ice and neutralised with sodium carbonate.
precipitated leuco-base is purified by recrystallisation from alcohol: its forms
needles, melting at 141° to 143° C. By treatment with oxidising agents this
leuco-base is transformed into a green-blue dyestuff.
2. By substituting in the preceding example for ortho-toluidine 20 kilos. of
benzyl-ortho-toluidine a leuco-base is formed which on oxidation yields a dyestuff
of blueish-green shade.
3. By substituting for the ortho-toluidine in the first example 16 kilos. of
dimethyl-ortho-toluidine, a leuco-base is obtained which likewise yields by
oxidation a blueish-green colouring matter.

page_text: In the examples above given, for the monohydrate may be substituted con-
centrated or feebly fuming sulphuric acid, also the temperature may be varied
within wide limits, but it must be considered that the condensation requires the
more time the more water there is contained in the condensing agent and the
lower the temperature is kept.
Tot
Ը
T
1000
ABEL & IMRAY,
Agents for the Applicant,
Manufacture of New Leuco-bases of the Triphenylmethane Series and
of Colouring Matters derived therefrom.
I, CHARLES DENTON ABEL, of Birkbeck Bank Chambers. Southampton Buildings,
in the County of London, Consulting Engineer and Chartered Patent Agent,
do hereby declare the nature of this invention (as communicated to me from
abroad by The Actien Gesellschaft für Anilin Fabrikation, of Berlin, in the
Empire of Germany, Chemical Manufacturers), and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement:-
-
It has been found by A. Kern that derivatives of triphenylmethane can be
obtained by condensing tetra-alkyldiamidobenzhydrol with amido-compounds
(compare German Patent [expired] No. 27,032.) According to all observations
hitherto published these condensations unexceptionally take place in such manner
that the (H-group of the hydrol enters into para-position to the amido-group if
this position is free (compare Nölting, Berichte der deutschen chemischen
Gesellschaft XXII, page 554). Only para-sulistituted amines have been observed
to yield condensation products which contain the CH-group in a different
position.
My foreign correspondents have now made the unexpected discovery that
certain amines with free para-position, such, for instance as ortho-toluidine and
its alkyl-derivatives vield quite different condensation products with hydrols,
if strong sulphuric acid is used as a condensing agent.
The leuco-bases thus obtained are essentially different from those heretofore
prepared from the same components.
For instance, by condensing benzyl-ortho-toluidine with tetramethyldiamido-
benzyhydrol in solution in monohydrate sulphuric acid, a new leuco-base is
formed which yields, when treated with oxidising agents, a green dyestuff, whereas
according to the German Patent No. 96230. only violet colouring matters can be
.obtained from the same components by the condensation methods hitherto
employed.
The following examples may serve to illustrate this invention.
1.) 27 kilos. of tetramethyldiamidobenzhydrol are dissolved in 160 kilos. of
monohydrate sulphuric acid and the solution thus obtained is introduced into
11 kilos of ortho-toluidine. The mass is then heated to 50° C. for about 12 hours
whereupon it is thrown on ice and neutralized with sodium carbonate. The
precipitated leuco-base is purified by recrystallisation from alcohol: its forms
needles, melting at 141° to 143° C. By treatment with oxidising agents this
leuco-base is transformed into a green-blue dyestuff.
2.) By substituting in the preceding example for ortho-toluidine 20 kilos. of
benzyl-ortho-toluidine a leuco-base is formed which on oxidation yields a dyestuff
of blueish-green shade.
8. By substituting for the ortho-toluidine in the first example 16 kilos, of

page_text: dimethyl-ortho-toluidine, a leuco-base is obtained which likewise yields by
oxidation a blueish-green colouring matter.
In the examples above given for the monohydrate may be substituted con-
centrated or feebly fuming sulphuric acid, also the temperature may be varied
within wide limits, but it must be considered that the condensation requires the
more time the more water there is contained in the condensing agent and the
lower the temperature is kept.
Having now particularly described and ascertained the nature of this
invention and in what manner the same is to be performed, I declare that what
I claim is:
1. The herein described manufacture of new leuco-bases of the triphenyl-
methane series by condensing tetraalkyldiamidobenzhydrol with ortho-toluidine
or its alkyl-derivatives in the presence of strong sulphuric acid.
2. The products manufactured as above set forth.
3. The transformation of the new leuco-bases referred to in Claim 1 into the
corresponding colouring matters by means of oxidizing agents as herein described.
4. The colouring matters manufactured as above set forth.
Dated this 15th day of January 1900.
ABEL & IMRAY,
Agents for the Applicant.