Improvements in the Manufacture and Production of Dyes belonging to the Rhodamine Series, and of New Materials for use in their Preparation.
Year: 1891

page_text: Date of Application, 27th Apr., 1891
Complete Specification Left, 23rd Jan., 1892-Accepted, 5th Mar., 1892
ΓΚΟΥΤΩΙΟΝΑΙ,
DIEVITICATION.
Improvements in the Manufacture and Production of Dyes belonging
to the Rhodamine Series, and of New Materials for use in their
Preparation.
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
invention 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 Specification of Letters Patent No. 15,374 of 1887 granted to me there
is described the manufacture of basic dyes of the rhodamine series by the con-
densation of di-alkyl-meta-amido-phenol with phthalic anhydride. These dyestuffs
have been widely applied in the dyeing industry as basic dyes, but it has not been
possible to convert them into sulpho-acids by direct sulphonation.
The present invention is based upon the discovery that by the application of the
process described in the aforesaid Specification to certain new benzylated meta-
amido-phenol derivatives these can be condensed with phthalic anhydride to yield
new basic rhodamine dyestuffs, which can also be converted, by direct sulphona-
tion, into sulpho-acids capable of use in dyeing in the same ways as the ordinary
acid dyestuffs are used.
The new benzylated-meta-amido-phenol-derivatives capable of use for the purposes
of this invention can be obtained by benzylating a mono-alkyl-derivative of meta-
sulphanilic acid by means of benzyl-chloride to obtain a new benzyl-alkyl-meta-
sulphanilic acid and then melting this new compound with a caustic alkali to
convert it into the desired meta-amido-phenol derivative.
The production of the new basic rhodamine dyes can be effected in the manner
described in the aforesaid Specification of Letters Patent No. 15,374 of 1887 but
substituting a new benzyl-alkyl-meta-amido-phenol for the di alkyl meta-amido-
phenol employed as described in that Specification.
To sulphonate the new basic dyes in order to obtain acid dyestuffs the finely
powdered basic dye is treated with fuming sulphuric acid containing say about
thirty per cent. free anhydride.
To more fully illustrate the nature of this invention I give the following
examples. The parts are by weight.
EXAMPLE 1-THE PRODUCTION OF ETHYL-BENZYL-METASULPHANILIC ACID.
Dissolve about ten parts of the sodium salt of mono-ethyl-metasulphanilic acid
in about twenty parts of hot water and add about sixty parts of benzyl-chloride
and heat on the water bath, add gradually about five parts of caustic soda solution
containing about thirty five per cent. of sodium hydrate (NaOH) taking care
that the temperature does not rise above ninety five degrees Centigrade. When
the benzyl-chloride has disappeared, pour the whole into about fifty parts of a
solution of common salt containing about twenty three per cent. of salt filter when
cold, press and dry.
The new ethyl-benzyl-metasulphanilic acid is thus obtained in the form of its
sodium salt.
If instead of mono-ethyl-metasulphanilic acid another mono-alkyl-compound be
taken the corresponding alkyl-benzyl derivative will be obtained.

page_text: UXAMPLE 2-THE PRODUCTION OF ETHYL-BENZYL-META-AMIDO-PHENOL.
Mix together about thirty parts of caustic potash and about two parts of water
and heat the mixture to about two hundred and forty to two hundred and fifty
degrees Centigrade. Stir well and add about fifteen parts of the sodium salt of
ethyl-benzyl-metasulphanilic acid (obtained as herein before described or in any
other way) raise the temperature to about two hundred and sixty to two hundred
and sixty five degrees Centigrade and maintain this temperature for about an hour.
Allow the melt to cool and when cold dissolve it in about one hundred parts of
water, filter, if necessary and add sufficient hydrochloric acid to set free the ethyl-
benzyl-meta-amido-phenol. Extract with ether which takes up this body, dry the
ethereal solution and then distil off the solvent. The meta-amido phenol derivative
remains behind as a light brown oily liquid which, on standing, solidifies to a
crystalline mass. It is soluble in alcohol, ether, benzene and in caustic alkalies.
If instead of ethyl-benzyl-metasulphanilic-acid other alkyl-benzyl-derivatives
of metasulphanilic acid be used, the corresponding alkyl-benzyl-meta-amido-phenol
can be obtained.
EXAMPLE 3-THE PRODUCTION OF A NEW BASIC RHODAMINE DYESTUFF,
DI-ETHYL-DI-BENZYL-RHODAMINE.
Mix together about forty five parts of ethyl-benzyl-meta-amido-phenol (obtained
as hereinbefore described or in any other way) with about thirty parts of phthalic
anhydride, and heat them together in an oil bath at a temperature of about one
hundred and seventy five to one hundred and eighty degrees Centigrade until no
further formation of colouring matter can be observed; this usually takes about
eight hours. Allow the mixture to cool, reduce it to powder and digest it for several
hours with a dilute ammonia solution.
The base of the colouring matter separates out and is dissolved in toluene, the
solution filtered and then shaken with dilute sulphuric acid. The di-ethyl-di-
benzyl-rhodamine separates out in the form of its sulphate which is thus obtained
as a reddish-brown body of pitch-like consistency and with a greenish lustre. On
washing with water this compound apparently partly decomposes into the free base
and sulphuric acid. In order to obtain this base pure, digest this mixture of the
base and the sulphate with dilute ammonia on the water bath until a test portion of
coloring matter dissolves completely in toluene. This point being arrived at,
cool, and when cold pour the aqueous solution off from the pitchy base and heat it
on the water bath until a sample when cold can be powdered.
The new rhodamine-base can thus be obtained as a brownish-red powder with a
green sheen, it is insoluble in water slightly soluble in dilute acids but readily
soluble in benzene and toluene. In alcohol it dissolves readily and the solution
shews the characteristic splendid yellow fluorescence. It dyes silk in shades
similar to those dyed by the rhodamines of the aforesaid Specification of Letters
Patent No. 15,374 of 1887.
If instead of ethyl-benzyl-meta-amido-phenol other alkyl-benzyl derivatives be
used, analogous rhodamines can be obtained also instead of phthalic anhydride
succinic anhydride, benzotrichloride and similar reagents which yield rhodamine
analogues by condensation with meta-amido-phenol derivatives can be employed
and analogous compounds be obtained. In some cases it is advantageous to add
a water-extracting reagent such as zinc chloride to the melt. .
EXAMPLE 4-THE PRODUCTION OF A NEW RHODAMINE SULPHO-ACID.
Take about ten parts of the di-ethyl-di-benzyl-rhodamine base (obtained as
hereinbefore described or in any other way) and stir them well into about fifty
parts of fuming sulphuric acid containing about thirty per cent. of free sulphuric

page_text: anhydride (SO3). Mix thoroughly till solution is complete and then pour the
mixture on to about two hundred and fifty parts of ice and filter off the sulpho
acid which separates out.
To purify re-dissolve in hot water filter to get rid of insoluble impurities, pre-
cipitate with common salt filter press and dry.
The sulpho acid so obtained is readily soluble in cold and hot water giving
fluorescent solutions. It dyes wool and silk from the acid bath giving beautiful red
shades which are fast to light and to alkalies.
The analogous bodies obtainable as hereinbefore described can be sulphonated
in the same way.
.
Dated the 27th day of April 1891
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, Agents.
COMPLETE SPECIFICATION.
Improvements in the Manufacture and Production of Dyes belonging
to the Rhodamine Series, and of New Materials for use in their
Preparation.
1
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 Specification of Letters Patent No. 15,374 of 1887 granted to me there
is described the manufacture of basic dyes of the rhodamine series by. the con-
densation of di-alkyl-meta-amido-phenol with phthalic anhydride. These dyestuffs
have been widely applied in the dyeing industry as basic dyes but it has not been
possible to convert them into sulpho acids by direct sulphonation.
The present invention is based upon the discovery that by the application of the
process described in the aforesaid Specification to certain new benzylated meta
amido phenol-derivatives, these can be condensed with phthalic anhydride to yield
new basic rhodamine dyestuffs which can also be converted by direct sulphonation
into sulpho-acids capable of use in dyeing in the same ways as the ordinary acid
dye stuffs are used.
The new benzylated meta-amido-phenol derivatives capable of use for the purposes
of this invention can be obtained by benzylating a mono-alkyl-derivative of meta-
sulphanilic acid by means of benzyl chloride to obtain a new benzyl-alkyl-meta
sulphanilic acid and then melting this new compound with a caustic alkali to
convert it into the desired meta-amido-phenol derivative.
The production of the new basic rhodamine dyes can be effected in the manner
described in the aforesaid Specification of Letters Patent No. 15,374 of 1887 but
substituting a new benzyl-alkyl-meta-amido-phenol for the di-alkyl-meta-amido-
phenol employed as described in that Specification.
To sulphonate the new basic dyes in order to obtain acid dyestuffs the finely
powdered basic dye is treated with fuming sulphuric acid containing say about
thirty per cent. free anhydride.
To more fully illustrate the nature of this invention and the manner in which
it can be carried into practical effect I give the following examples. The parts
are by weight

page_text: heat on the water-bath; add, gradually, about five parts of caustic soda solution
containing about thirty-five per cent. of sodium hydrate (NaOH) taking care
that the temperature does not rise above ninety-five degrees Centigrade. When
the benzyl chloride has disappeared pour the whole into about fifty parts of a
solution of common salt containing about twenty-three per cent. of salt, filter when
cold, press and dry.
The new ethyl-benzyl-meta-sulphanilic acid is thus obtained in the form of its
sodium salt.
If instead of mono-ethyl-meta-sulphanilic acid the equivalent quantity of the
mono-methyl or of another mono-alkyl-compound be taken and subjected to the
treatment above described the corresponding alkyl-benzyl derivative will be
obtained.
EXAMPLE 2-THE PRODUCTION OF ETHYL-BENZYL META-AMIDO-PHENOL.
Mix together about thirty parts of caustic potash and about two parts of water
and heat the mixture to about two hundred and forty to two hundred and fifty
degrees Centigrade. Stir well and add about fifteen parts of the sodium-salt of
ethyl-benzyl-meta sulphanilic acid (obtained as hereinbefore described or in any
other way), raise the temperature to about two hundred and sixty to two
hundred and sixty five degrees Centigrade and maintain this temperature for about
an hour. Allow the melt to cool and when cold dissolve it in about one hundred
parts of water filter, if necessary, and add sufficient hydrochloric acid to set free
the ethyl-benzyl-meta-amido-phenol. Extract with ether which takes up this body,
dry the ethereal solution and then distil off the solvent. The meta-amido-phenol-
derivative remains behind as a light brown oily liquid which, on standing, solidifies
to a crystalline mass. It is soluble in alcohol, ether, benzene and in caustic
alkalies.
'
If instead of ethyl-benzyl-meta-sulphanilic-acid the methyl-benzyl or another
alkyl-benzyl-derivative of meta-sulphanilic acid be used in the above process the
corresponding alkyl-benzyl-meta-amido-phenol can be obtained.
EXAMPLE 3-THE PRODUCTION OF A NEW BASIC
RHODAMINE-DYESTUFF:
DI-ETHYL-DI-BENZYL-RHODAMINE.
Mix together about forty-five parts of ethyl-benzyl-meta-amido-phenol (obtained
as herein before described or in any other way) with about thirty parts of phthalic
anhydride and heat them together in an oil bath at a temperature of about one
hundred and seventy five to one hundred and eighty degrees Centigrade until no
further formation of colouring matter can be observed, which usually takes about
eight hours. Allow the mixture to cool, reduce it to powder and digest it for
several hours with a dilute ammonia solution. The base of the colouring matter
separates out and is dissolved in toluene; the solution is filtered and then shaken
with dilute sulphuric acid. The diethyl-di-benzyl-rhodamine separates out in the
form of its sulphate which is thus obtained as a reddish-brown body of pitch-like
consistency and with a greenish lustre. On washing with water this compound
apparently partly decomposes into the free base and sulphuric acid. In order to
obtain the base pure digest this mixture of the base and the sulphate with dilute
ammonia on the water bath until a test portion of the colouring matter dissolves
completely in toluene. This point being arrived at, cool and when cold pour the
aqueous solution off from the pitchy base and heat it on the water bath until a
sample, when cold, can be powdered. The new rhodamine base can thus be obtained
as a brownish-red powder with a green sheen, it is insoluble in water, slightly
.soluble in dilute acids, but readily soluble in benzene and toluene. In alcohol it
dissolves readily and the solution shews the characteristic splendid yellow fluor-
escence. It dyes silk in shades similar to those dyed by the rhodamines produced
as described in the aforesaid Specification of Letters Patent No. 15,374 of 1887.

page_text: If instead of ethyl-benzyl-meta-amido-phenol the methyl or another alkyl-
benzyl derivative be used, analogous rhodamines can be obtained; also instead of
phthalic anhydride, succinic anhydride, benzotrichloride, formaldehyde, and similar
reagents which either directly or indirectly yield rhodamine analogues by con-
5 densation with meta-amido-phenol derivatives can be employed and analogous
compounds.be obtained. In some cases it is advantageous to add a water extracting
reagent (such as zinc-chloride for instance) to the melt.
EXAMPLE 4 THE PRODUCTION OF NEW RHODAMINE SULPHO-ACIDS.
Take about ten parts of the di-ethyl-di-benzyl rhodamine base (obtained as
hereinbefore described or in any other way) and stir them well into about fifty
parts of fuming sulphuric acid containing about thirty per cent. of free sulphuric
anhydride (SO). Mix thoroughly till solution is complete and then pour the
mixture on to about two hundred and fifty parts of ice and filter off the sulpho-
acid which separates out. To purify, redissolve in hot water, filter to get rid of
insoluble impurities, precipitate with common salt, filter press and dry.
The sulpho-acid so obtained is readily soluble in either cold or hot water-giving
fluorescent solutions. It dyes wool and silk from the acid bath giving beautiful
red shades which are fast against the action of light and alkalies.
The analogous bodies obtainable as hereinbefore described can be sulphonated in
the same way.
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 manufacture of new benzylated dyes of the rhodamine series by first
preparing a benzyl-alkyl-meta-sulphanilic acid, then converting this into a benzyl-
alkyl-meta-amido phenol, and finally combining this with phthalic anhydride, to
obtain a benzyl alkyl rhodamine all substantially as herein before described.
2. The manufacture of acid dyes of the rhodamine series by first preparing a
benzylated rhodamine by the process or series of processes claimed under the
preceding claiming clause and then sulphonating this compound substantially as
hereinbefore described.
3. The manufacture of ethyl- (or methyl-) benzyl-sulphanilic acid by treatment
of ethyl- (or methyl-) meta-sulphanilic acid with benzyl-chloride substantially as
herein before described under Example 1.
4. The manufacture of ethyl- (or methyl-) benzyl-meta-amido-phenol by sub-
jecting ethyl-(or methyl-) benzyl-meta-sulphanilic acid to the action of a caustic
alkaline melt substantially as hereinbefore described under Example 2.
5. The application of ethyl- (or methyl-) benzyl-meta-amido-phenol to the
manufacture of rhodamine dyes by condensation with a reagent capable of con-
densation with meta-amido-phenol-derivatives for this purpose.
6. The manufacture of di-ethyl- (or dimethyl-) di-benzyl-rhodamine by the
condensation of ethyl- (or methyl-) benzyl-meta-amido-phenol with phthalic
anhydride substantially as herein before described under Example 3.
7. The manufacture of new rhodamine sulpho-acids by sulphonating di-ethyl-
(or dimethyl-) di-benzyl-rhodamine substantially as herein before described under
Example 4.
8. The new products of manufacture :-

page_text: :
which constitute new materials for use in the manufacture of rhodamines and the
new dyes
Di-ethyl-di-benzyl-rhodamine
Di-methyl-di-benzyl-rhodamine and
Sulphonated di-ethyl-di-benzyl-rhodamine
Sulphonated di-methyl-di-benzyl rhodamine
all such as result from the processes hereinbefore described and claimed.
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C., Agents.