Improvements in the Manufacture of Triphenylmethane Dyestuffs.
Year: 1892

page_text: Date of Application, 6th May, 1892
Complete Specification Left, 18th Jan., 1893-Accepted, 25th Feb., 1893
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Triphenylmethane Dyestuffs.
I, JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of
Middlesex Gentleman do hereby declare the nature of this invention (which has
been communicated to me from abroad by The Badische Anilin and Soda Fabrik
of Ludwigshafen on Rhine in the Empire of Germany) to be as follows:-
:―
In the year 1858 A. W. Hofmaun observed that fuchsine could be produced by
the action of carbon tetra-chloride on aniline. This reaction however does not
proceed smoothly and it was found impossible to base a commercial manufacture of
fuchsine upon it. Since then carbon tetra-chloride does not appear to have been
used in preparing dyes. The present invention relates to the discovery, that by
acting on certain secondary and tertiary aromatic bases, simultaneously with
carbon tetra-chloride and certain condensation agents, such as for instance,
aluminium chloride, dyes of the tri-phenyl-methane series can be obtained.
The reaction usually takes place at or about a temperature of one hundred
degrees centigrade especially if aluminium chloride be used as the condensing
agent and in this case it is usually sufficient to heat the mixed reagents a few
hours on the water bath while stirring continuously. If other chloride such as
zinc chloride or ferric chloride for instance be used, a higher temperature is
necessary.
The following aromatic bases have given good results viz. :-
Methyl-diphenyl-amine
Di-ethyl-aniline
Di-methyl-aniline
but others can also be used. The bases employed can be used either alone or in
admixture with one another.
From methyl-diphenyl-amine, the known blue dye is obtained which can also be
prepared from the same amine by the aid of oxalic acid. This dye is soluble in
alcohol giving a blue solution and can by sulphonation, be converted into an acid
dye which dyes wool beautiful blue shades. By applying the new process to di-
ethyl- and dimethyl-aniline the dyes known in commerce as Ethyl-violet" and
Crystal violet" respectively, result.
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The following examples will serve to further illustrate the nature of the inven-
tion, but their details are susceptible of great variation without altering the nature o
of the reaction.
EXAMPLE 1.
PREPARATION OF METHYL-DIPHENYL-AMINE BLUE.
Take about one hundred and fifty parts of methyl-diphenyl-amine and about
seventy five parts of aluminium chloride and mix them, in a suitable vessel
provided with a stirrer and inverted condenser. Keep the mixture well cooled till
all the condensing agent is mixed in, then raise the temperature to about seventy
degrees centigrade and, while maintaining this heat, run in gradually (say during
about two hours) about seventy parts of carbon tetra-chloride. Stir continuously
and raise the temperature for about six hours to about ninety to one hundred

page_text: methyl-diphenyl-amine. The colouring matter is thus obtained and can readily
be reduced to powder; it can be sulphonated in the well known way by the aid of
fuming sulphuric acid."
EXAMPLE 2.
PREPARATION OF ETHYL-VIOLET.
Mix together about one hundred and eighty parts of diethyl-aniline, about
twenty-five parts aluminium chloride and about thirty two parts of carbon-
tetra chloride, and heat the mixture, in a suitable vessel, provided with a stirrer
and with an inverted condenser for about four hours to a temperature of about
seventy to eighty degrees centigrade, then for a further period of six hours to
about one hundred to one hundred and ten degrees. Treat the melt with an excess
of caustic soda solution and distil off the unused diethyl-aniline with steam. 'Dis-
solve the residue in hot water containing sufficient hydrochloric acid to neutralize
the base, filter, precipitate the colouring matter with common salt, collect and dry.
If instead of diethyl-auiline the equivalent quantity of di-methyl-aniline be used
crystal violet is obtained.
Dated this 6th day of May 1900
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in the 'Manufacture of Triphenylmethane Dyestuffs.
I, JAMES YATE JOHNSON of 47 Lincoln's Inn Fields, in the County of
Middlesex, Gentleman, do hereby declare the nature of this invention' (which 'has
been communicated to me from abroad by The Badische Anilin and Soda Fabrik of
Ludwigshafen on Rhine, in the Empire of Germany) and in what manner the
same is to be performed to be particularly described and ascertained in and by the
following, statement:
In the year 1858 A. W. Hofmann observed that fuchsine could be produced by
the action of carbon-tetra chloride on aniline. This reaction however does not
proceed smoothly and it was found impossible to base a commercial manufacture of
fuclisine upon it. Since then carbon-tetra-chloride does not appear to have been
used in preparing dyes. The present invention relates to the discovery that by
acting on certain secondary and tertiary aromatic bases, simultaneously with carbon-
tetra-chloride and certain condensation agents especially aluminium chloride, dyes
of the tri-phenyl-methane series can be obtained. The reaction usually takes
place, at or about a temperature of one hundred degrees centigrade especially if
aluminium chloride be used as the condensing agent and in this case it is usually
sufficient to heat the mixed reagents a few hours on the water bath while stirring
continuously. If other condensing agent, say .zinc chloride or ferric chloride, be
used, a higher temperature is necessary.
The following aromatic bases have given good results viz. :-
Methyl-diphenyl-amine.
Di-ethyl-aniline.
Di-methyl-aniline.
From methyl-diphenyl-amine, the known blue dye is obtained which can also be
prépared from the same amine by the aid of oxalic acid. This 'dye is soluble in
alcohol giving a blue solution and can, by sulphonation, be converted into an acid
dye which dyes wool beautiful blue shades. By applying the new process to di-
ethyl- and di-methyl-aniline the dyes known in commerce as "Ethyl-violet" and
Crystal-violet" respectively, result.
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"The following examples will serve to further illustrate the nature of the invention

page_text: and the manner in which it can be carried into practical effect but their details are
susceptible of variation in many respects without altering the nature of the reaction.
The parts are by weight.
EXAMPLE 1.
PREPARATION OF METHYL-DI-PHENYL-AMINE-BLUE.
Take about one hundred and fifty parts of methyl-di-phenyl-amine and about
Beventy five parts of aluminium chloride, and mix them in a suitable vessel
provided with a stirrer and inverted condenser. Keep the mixture well cooled till
all the condensing agent is mixed in, then raise the temperature to about seventy
degrees centigrade and, while maintaining this heat, run in gradually, (say during
about two hours) about seventy parts of carbon-tetra-chloride. Stir continuously
and raise the temperature for about six hours to about ninety to one hundred
degrees centigrade.
Next boil the melt (which has assumed a copper coloured metallic sheen)
repeatedly with water to extract the chloride of aluminium, and finally extract the
residue with toluene or a similar solvent to remove unused methyl-di-phenyl-amine.
The colouring matter is thus obtained and can readily be reduced to powder; it
can be sulphonated in the well known way by the aid of fuming sulphuric acid.
PREPARATION OF ETHYL-VIOLET.
Mix together about one hundred and eighty parts of di-ethyl-aniline, about
twenty five parts aluminium chloride and about thirty two parts of carbon-tetra-
chloride, and heat the mixture, in a suitable vessel, provided with a stirrer and
with an inverted condenser, for about four hours, to a temperature of about seventy
to eighty degrees centigrade and then for a further period of six hours to about
one hundred to one hundred and ten degrees. Treat the melt with an excess of
caustic soda-solution and distil off the unused di-ethyl-aniline with steam. Dis-
solve the residue in hot water containing sufficient hydrochloric acid to neutralize
the base, filter, precipitate the colouring matter with common salt, collect, and dry.
If instead of di-ethyl-aniline the equivalent quantity of di-methyl-aniline be
used crystal-violet is obtained.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
:-
1. The manufacture of tri-phenyl-methane dyestuffs by heating an aromatic
base such as methyl-diphenyl-amine, di-methyl-aniline, or di-ethyl-aniline with
carbon-tetra-chloride and a condensing agent, substantially as hereinbefore
described.
2. The manufacture of di-phenyl-amine-blue, ethyl-violet, and crystal-violet,
substantially in the manner and from the materials herein described under the
foregoing examples.
Dated this 18th day of January 1893.
J. H. JOHNSON & Co.,
Agents.