Improvements in the Manufacture of Colouring Matters of the Rhodamine Series
Year: 1897

page_text: Date of Application, 1st Feb., 1897
Complete Specification Left, 1st Nov., 1897-Accepted, 4th Dec., 1897
PROVISIONAL SPECIFICATION.
"Improvements in the Manufacture of Colouring Matters of the
Rhodamine Series.”
I, JAMES YATE JOHNSON of 47 Lincolns Inn Fields in the County of London,
Gentleman, do hereby declare the nature of this Invention (which has been com-
municated to me from Abroad by the Badische Anilin and Soda Fabrik of
Ludwigshafen-on-Rhine in the Empire of Germany) to be as follows:-
It is known that by condensing benzylated alkyl-meta-amido-phenols with
phthalic anhydride, dibenzyl-dialkyl rhodamines are produced, and that the dye-
stuffs so obtained yield on treatment with fuming sulphuric acid soluble acid
colouring matters which dye wool and silk from the acid bath giving the
characteristic rhodamine shades.
My foreign Correspondents have now discovered that also mono-benzyl-
rhodamines and rhodols can be prepared and by sulphonation also can be converted
into valuable colouring matters.
The said mono-benzylated rhodamines can for instance, be obtained by melt-
ing together an alkyl-benzyl-meta-amido-phenol with phthalic anhydride in the
manner described in Example 3 of the Specification of Letters Patent No. 7258
of 1891 but at a temperature not exceeding from 120 to 140 degrees Centigrade
and then condensing the product so obtained with a meta-amido-phenol, alkylated
or not, with the aid of a condensing agent. In the same way monobenzylrhodols
can be obtained by using resorcinol instead of meta-amido-phenol.
Theoretically it might be expected that from these mono-benzylated products
only one series of sulphoacids could he obtained at least when all hydrogen atoms
of the amido groups are substituted by alkyls (the tetra-alkyl-rhodamines cannot
be sulphonated but my foreign Correspondents have found that by varying the
conditions of sulphonation principally two series of sulphoacids are obtained
which differ from one another to a considerable degree in their practical qualities.
The monobenzylated rhodamines (whether otherwise alkylated or not) can
readily be sulphonated by treatment with ordinary sulphuric acid at the tempera-
ture of the water bath. The products so obtained possess the remarkable property
of being readily fixed, like basic dyes, on tanning mordanted cotton whilst only
weakly colouring wool and silk from the acid bath.
The other series of sulpho-acids can for instance be obtained by sulphonating
with fuming sulphuric acid in the cold. These products dye wool and silk very
beautifully from the acid bath and the shades obtained with some of these colour-
ing matters exhibit, even on wool, the characteristic fluorescence of rhodamine.
Also the dibenzyl-dialky-rhodamines above mentioned (the known sulpho acids
of which belong to the second series) can be made, on sulphonation with concen-
trated sulphuric acid, to yield the sulphoacid of the first series which dye tannin
mordanted cotton.
If phthalic anhydride be condensed first with benzyl-alkyl-meta-amido-phenol
and then with an alphylated meta-amido-phenol such as ortho-tolyl-meta-amido-

page_text: prenor Benzylated and apoyfaved rhodamines are obtained. inese, on ѕurропа-
tion, also yield principally two series of sulpho acids, both of which however are
chiefly suitable for application to wool and silk.
The following examples will serve to illustrate the nature of the invention but
they are merely typical cases and can be varied without departure from the unture
of the invention.
The parts are by weight.
EXAMPLE 1.
Heat about 23 parts of ethyl-benzyl-meta-amido-phenol and about 15 parts of
phthalic anhydride (whilst stirring) for an hour at a temperature of about One
hundred and twenty five degrees centigrade until the melt solidifies to a crystalline
mass representing the phthalic acid compound of ethyl-benzyl-meta-amido-phenol.
Add about sixteen and one half parts of diethyl-meta-amido-phenol; heat to a
temperature of about One hundred and thirty degrees centigrade until the mass
has become uniformly molten, then add thirty parts of potassium bisulphate and
raise the temperature to One hundred and seventy five degrees centigrade.
When no further increase in the formation of the colouring matter is observed
and the melt has become thick (say after an hour) cool, pulverize, extract the
potassium sulphates and dry the residue. It mainly consists of the sulphate of
tri-ethyl-benzyl-rhodamine.
EXAMPLE 2.
1
Mix together about ninety five parts of the phthalic acid compound of ethyl-
benzyl-meta-amido-phenol (either in the form of the crude crystalline mass
mentioned in Example 1, or the compound isolated and purified by dissolving the
said crude mass in soda solution and reprecipitating with acetic acid), thirty five
parts of mono-ethyl-meta-amido-phenol and eighty parts of potassium bisulphate,
and heat the mixture (whilst stirring thoroughly) to a temperature of about one
hundred and seventy five degrees centigrade. The mixture melts at about ninety
degrees centigrade, and at about one hundred and sixty five degrees centigrade,
assumes a brassy lustre which subsequently increases. The melt gradually
becomes stiff and after about an hour can only be stirred with difficulty. When
no further increase in the formation of the colouring matter is observed, reduce
to powder and extract with boiling water, when the colouring matter will melt
to a pitchy mass; finally dry and powder again.
In a similar manner analogous mono-benzylated rhodamines can be obtained
by using, in the given Examples, other alkylated benzyl-meta-amido-phenol and
meta-amido-cresol derivatives on the one hand and other meta-amido-phenols or
cresols, substituted or not, on the other hand.
1
In an analogous manner also alkyl-benzyl-rhodol-compounds can be obtained
by using in the above Examples instead of the alkylated meta-amido-phenol, the
equivalent quantity of resorcinol. These colouring matters differ from the above
mentioned by their increased acid nature.
Of the mono-benzylated rhodamine colouring matters so obtained those which
contain four substituting groups can also be obtained from the phthalic acid com-
pounds of dimethyl- and diethyl-meta-amido-phenol by heating them with ethyl,
or methyl-benzyl-meta-amido-phenol and potassium bisulphate.
EXAMPLE 8.
Dissolve one part of tri-ethyl-benzyl-rhodamine-sulphate (see Example 1) in
about seven parts of ordinary concentrated sulphuric acid, and warm on the water-
bath until a test portion dissolves in dilute soda solution which will be effected in
a very short time. Then pour the mass into ten parts of water, filter the separated
sulphoacid, dissolve it in hot water adding the necessary quantity of sodium
carbonate and salt out the sodium salt by means of common salt.
In a similar manner the other alkylated or rhodamine- or rhodol-dyestuffs which

page_text: contain a benzyl group and the diethyl (dimethyl) dibenzylrhodamine can be con-
verted into products soluble in water and possessing analogous properties.
EXAMPLE 4.
Dissolve one part of the tri-ethyl-benzyl-rhodamine-sulphate in about five parts
of fuming sulphuric acid whilst cooling, so that a temperature of fifteen degrees
centigrade is not exceeded. When solution has taken place, pour at once upon
a not too abundant quantity of ice and water. The separated sulphoacid, which.
is more soluble in water than that obtained with ordinary sulphuric acid, is con-
verted into the sodium salt in the abovo described manner.
In an analogous manner the other mono-benzylated rhodamines and rhodola
can be converted into sulpho-acids with similar properties.
Rhodamine Series."
I, JAMES YATE JOHNSON of 47 Lincolns Inn Fields, in the County of London,
Gentleman, do hereby declare the nature of this Invention (which has been com-
municated to me from abroad by the Badische Anilin and Soda Fabrik of Ludwigs-
hafen-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 follow-
ing statement: —
It is known that by condensing benzylated alkyl-meta-amido-phenols with
phthalic anhydride, dibenzyl-dialkyl-rhodamines are produced, and that the dye-
stuffs so obtained on treatment with fuming sulphuric acid yield soluble acid
colouring matters which dye wool and silk from the acid bath, giving the
characteristic rhodamine shades.
My foreign Correspondents have now discovered that also mono-benzyl-
rhodamines and mono-benzyl rhodols can be prepared and also that they can be
converted into valuable colouring matters by sulphonation.
The said mono-benzylated rhodamines can, for instance, be obtained by melt-
ing together an alkyl- benzyl-meta-amido-phenol with phthalic anhydride in the
manner described in Example 3 of the Specification of Letters Patent No 7258
of 1891 but at a temperature not exceeding from 120 to 140 degrees centigrade
and then condensing the product so obtained with a meta-amido-phenol, or the
ortho-amido-para-cresol (either being alkylated or not) by means of a condensing
agont. In the same way mono-benzyl-rhodols can be obtained by using resorcinol
instead of meta-amido-phenol. The mono-benzylated rhodamines further can be
obtained by melting together in an analogous way, a dialkyl-meta-amido-phonol
with phthalic anophydride and then condensing the product so obtained with an
alkyl-benzyl-meta-amido-phenol.
Theoretically it might be expected that from these mono-benzylated products
only one series of sulphoacids could be obtained, at least when all hydrogen atoms
of the amido-groups are substituted by alkyls (the tetra-alkyl rhodamines cannot
be sulphonated) but my foreign Correspondents have found that by varying the
conditions of sulphonation principally two series of sulpho acids are obtained
which differ from one another to a considerable degree in their practical qualities.

page_text: The mono-benzylated rhodamines and rhodols (whether otherwise alkylated or
not) can readily be sulphonated by treatment with ordinary sulphuric acid at
the temperature of the water bath. The products so obtained possess the remark-
able property of being readily fixed, like basic dyes, on tannin mordanted cotton
whilst they only weakly colour wool and silk from the acid bath.
The other series of sulpho acids can for instance be obtained by sulphonating
with fuming sulphuric acid in the cold. These products dye wool and silk very
beautifully from the acid bath and the shades obtained with some of these colour-
ing-matters exhibit, even on wool, the characteristic fluoresence of rhodamine.
Similar sulphoacids can be obtained, if the dialkyl-mono-benzyl-rhodamine the
preparation of which is hereinafter described in Example 2, be treated with
sulphonating agents in an analogous manner.
Also the dibenzyl-dialkyl-rhodamines above mentioned (the known sulphoacids
of which belong to the second series) can be made, on sulphonation with concen-
trated sulphuric acid, to yield the sulphoacid of the first series which dye tannin
mordanted cotton.
If phthalic anhydride be condensed first with benzyl-alkyl-meta-amido-phenol
and then with an alphylated meta-amido-phenol such as ortho-tolyl-meta-amido-
phenol, benzylated and alphylated rhodamines are obtained. These, on sulphona-
tion also, yield principally two series of sulphoacids, both of which however are
chiefly suitable for application to wool and silk.
The following examples will serve to illustrate the nature of the invention,
and the manner in which it can be performed, but they are given merely as
typical cases and can be varied without departure from the nature of the inven-
tion. The parts are by weight.
EXAMPLE 1.
Heat about twenty three parts of ethyl-benzyl-meta-amido-phenol and about
fifteen parts of phthalic anhydride (whilst stirring) for an hour at a temperature
of about one hundred and twenty five degrees centigrade until the melt solidifies
to a crystalline mass representing the phthalic acid compound of ethyl-benzyl-
meta-amido-phenol. Add about sixteen and one half parts of diethyl-meta-amido-
phenol; heat to a temperature of about one hundred and thirty degrees centigrade
until the mass has become uniformly molten, then add thirty parts of potassium
bisulphate and raise the temperature to one hundred and seventy five degrees
centigrade. When no further increase in the formation of the colouring-matter
is observed and the melt has become thick (which usually occurs in about an
hour), cool, pulverize, extract the potassium sulphates, and dry the residue. It
mainly consists of the sulphate of tri-ethyl-benzyl-rhodamine.
EXAMPLE 2.
Mix together ninety five parts of the phthalic acid compound of ethyl-benzyl-
meta-amido-phenol (either in the form of the crude crystalline mass mentioned
in Example 1. or the compound isolated and purified by dissolving the said crude
mass in soda solution and reprecipitating with acetic acid) thirty five parts of
mono-ethyl-meta-amido phenol and eighty parts of potassium bisulphate, and
heat the mixture (whilst stirring thoroughly) to a temperature of about one
hundred and seventy five degrees centigrade. The mixture melts at about ninety
degrees centigrade and at about one hundred and sixty five degrees centigrade,
assumes a brassey lustre which subsequently increases. The melt gradually
becomes stiff, and after about an hour can only be stirred with difficulty. When
no further increase in the formation of the colouring matter is observed, reduce
to powder and extract with boiling water, when the colouring matter will melt
to a pitchy mass. Finally dry and powder again.
In a similar manner analogous mono-benzylated rhodamines can be obtained
by using in the given examples other alkylated benzyl-meta-amido-phenol, and
meta-amido-cresol derivatives on the one hand, and other meta-amido-phenols or
cresols substituted or not, on the other hand.

page_text: In an analogous manner also alkylbenzyl-rhodol-compounds can be obtained by
using in the above examples, instead of the alkylated-meta-amido-phenol there
given, the equivalent quantity of resorcinol. These colouring matters differ from
those before mentioned by their increased acid nature.
Of the monobenzylated rhodamine colouring matters so obtained those which
contain four substituting groups can also be obtained from the phthalic acid
compounds of dimethyl and diethyl-meta-amido-phenol by heating them with
ethyl or methyl, benzyl-meta-amido phenol and potassium bisulphate. Further,
in operating according to the way last mentioned, instead of the alkyl benzyl meta-
amido-phenols, the mono-benzl-meta-amido phenol can be used, which can be
obtained by heating together equal molecular proportions of resorcinol and benzyl-
amine, to about two hundred degrees centigrade for about 5 hours.
EXAMPLE 3.
Dissolve one part of tri-ethyl-benzyl-rhodamine-sulphate (see example 1) in
about seven parts of ordinary concentrated sulphuric acid, and warm on the water
bath until a test portion dissolves in dilute soda solution, which will be effected.
in a very short time. Then pour the mass into ten parts of water, filter the
separated sulphoacid, dissolve it in hot water, adding the necessary quantity of.
sodium carbonate, and salt out the sodium salt by means of common salt.
In a similar manner the other alkylated rhodamine or rhodol dyestuffs which
contain a benzyl group, and the diethyl (dimethyl) dibenzyl-rhodamine can be
converted into products soluble in water and possessing analogous properties.
EXAMPLE 4.
Dissolve one part of the tri-ethyl-benzyl-rhodamine sulphate in about five parts.
of fuming sulphuric acid whilst cooling, so that a temperature of fifteen degrees
centigrade is not exceeded. When solution has taken place, pour at once upon
a not too abundant quantity of ice and water. The separated sulphoacid, which
is more soluble in water than that obtained with ordinary sulphuric acid, is con-
verted into the sodium salt in the above described manner.
In an analagous manner, the other mono-benzylated rhodamines and rhodols
can be converted into sulphoacids with similar properties.
Having now particularly described and ascertained the nature of my said Inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
(1) The manufacture of mono benzyl rhodamines by melting together an alkyl-
benzyl- meta-amido-phenol with phthalic anhydride and then condensing the pic-
duct so obtained with a meta-amido-phenol or ortho-amido-para-cresol alkylated
or not or alphylated by the aid of a condensing agent substantially as herein before
described.
(2) The manufacture of mono-benzyl-rhodamines by melt.ng together a dialkyl-
meta-amido-phenol with phthalic anhydride and then condensing the product so
obtained with an alkyl-benzyl-meta-amido phenol by the aid of a condensing
agent, substantially as hereinbefore described.
3. The manufacture of mono-benzyl rhodols by replacing, in the process of the
foregoing, first claiming clause, the second derivative of meta-amido, phenol by
resorcinol, substantially as hereinbefore described.
(4) The manufacture of acid dyes of the rhodamine and rhodol-series by first
preparing a mono-benzylated rhodamine or rhodol by the process or series of
processes claimed under the preceding first, second and third claiming clauses, or
by melting together a dialkyl-meta-amido phenol with phthalic anhydride and
then condensing this product with mono-benzyl-meta-amido phenol, and treating
the products thus obtained with sulphonating agents, substantially as hereinbefore
described.
(5) The manufacture of acid dyes of the rhodamine and rhodol series suitable

page_text: to be fixed on tannin mordanted cotton like basic dyes, by heating the products
obtained according to the preceding first second and third claiming clauses with
ordinary sulphuric acid at the temperature of the water bath, substantially as
herein before described.
(6) The manufacture of acid dyes of the rhodamine and rhodol series, suitable
for dyeing wool and silk, by treating the products obtained according to the pre-
ceding first, second and third claiming clauses, with fuming sulphuric acid in
the cold, substantially as hereinbefore described.
(7) The manufacture of acid dyes of the rhodamine series by first preparing a
mono-benzyl rhodamine by melting together dialkyl-meta-amido-phenol with
phthalic anhydride and condensing the product so obtained with an alkyl-benzyl-
meta amido phenol, and then treating this mono-benzyl-rhodamine either with
ordinary sulphuric acid at the temperature of the water-bath, or with fuming
sulphuric acid in the cold, substantially as hereinbefore described.
(8) The manufacture of benzylated and alphylated rhodamine sulphoacids by
first condensing phthalic anhydride with benzyl-alkyl-meta-amido-phenol and
then with an alphylated meta-amido-phenol such as ortho-tolyl-meta-amido-
phenol and then treating the products obtained, either with ordinary sulphuric
acid at the temperature of the water bath, or with fuming sulphuric acid in the
cold, substantially as hereinbefore described.
(9) The manufacture of sulphoacids of the dibenzyl-dialkyl-rhodamines
described in the Specification of Letters Patent No 7258 of 1891 by sulphonating
them with concentrated sulphuric acid instead of free sulphuric anhydride (S O₁₂)
substantially as hereinbefore described.
(10) The manufacture of mono-benzyl rhodamines and rhodols, and their sulpho-
acids as hereinbefore described in the examples.
'
(11) As new products of manufacture the rhodamine and rhodols and their
sulphoacids such as result from the processes herein before described and claimed.
Dated this 1st day of November 1897.
JOHNSONS & WILLCOX
47 Lincolns Inn Fields London W.C.
Agents.