Matters suitable for Dyeing and Printing.
Year: 1887

page_text: Date of Application, 10th Nov, 1887
Complete Specification Left, 10th Aug., 1888
Complete Specification Accepted, 14th Sept., 1888
Matters suitable for Dyeing and Printing.
I JAMES YATE JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of this Invention which has been communi-
cated to me from abroad by the Badische Anilin and Soda Fabrik of Ludwigshafen
on the Rhine in the Empire of Germany to be as follows:-
This Invention relates to the production of red coloring matters suitable for dyeing
and printing they belonging to a new series of Phthaleines which result from the
condensation of one molecule of Phthalic anhydride or of its halogen-substitution-
products with two molecules of meta-amidophenol or of its alkyl-derivatives.
The said new series of Phthaleines comprises within itself a large number of coloring
matters capable of producing various shades of reds ranging from a reddish-yellow to
a reddish-purple in dyeing and printing and differing from the Phthaleines hitherto in
uso by their basic character. To the entire group of colouring matters belonging to
the said new series of Phthaleines the generic name of "Rhodamines" may therefore
hereafter be applied.
The coloring matters produced according to the present Invention are alkylized
Rhodamines produced by the condensation of one molecule of phthalic anhydride with
two molecules of dimethyl or of diethyl-meta-amidophenol.
The said methyl or ethyl-derivatives of meta-amidophenol have 1 believe remained
hitherto unknown. They may be obtained from meta-amidophenol by an application
of the known or suitable methods of alkylizing amido-compounds. For instance a
mixture of Hydrochlorate of meta-amidophenol with methylic alcohol is heated in a
closed digester during about eight hours at a temperature of about 170° Centigrade. The
excess of methylic alcohol having been recovered by distillation the residuary hydro-
chlorate of dimethyl-meta-amidophenol is then decomposed by Carbonate of Soda and
the phenolic body, thus set free, is extracted with Ether. The ether is then distilled
off and the crude dimethyl-meta-amidophenol thus obtained is purified by crystallization
from boiling ligroine or from other suitable solvents. In its pure state dimethyl-
meta-amidophenol is a white crystalline solid fusing at 86° Centigrade.
In an analogous manner diethyl-meta-amidophenol may be obtained from meta-
amidophenol by heating a mixture of the hydrochlorate of meta-amidophenol with
ethylic alcohol in a closed digester during about ten hours at a temperature of about

page_text: At first the
170° Centigrade. The excess of ethylic alcohol having been recovered by distillation,
the residuary hydrochlorate of crude diethyl-meta-amidophenol is then decomposed
by Carbonate of Soda and the Phenolic body thus set free is extracted with ether.
The ether is then distilled off and the crude diethyl-meta-amidophenol thus obtained
is first purified by distillation in a current of Carbonic Acid gas. A further purification
is effected by dissolving the distillate in dilute acetic acid and by fractionally
precipitating the solution thus obtained with Carbonate of Soda.
impurities are precipitated and then a further addition of the precipitant separates
oily drops which upon being placed in contact with a small fragment of crystallized
diethyl-meta-amidophenol, solidify into a white crystalline mass of the purified
product. By a final crystallization from a mixture of Sulphide of Carbon and
petroleum or from other suitable solvents diethyl-meta amido-phenol may be obtained
în well defined compact crystals fusing at 74° Centigrade.
The following is an example of the manner in which the above named dimethyl-
meta-amidophenol may be condensed with phthalic anhydride in order to produce the
correspondingly alkylized Rhodamine.
An intimate mixture of about 10 parts by weight of dimethyl-meta-amidophenol
with about twelve parts by weight of Phthalic anhydride is heated in an enamelled
digester provided with an agitator and fitted up within an oil bath the temperature of
which is kept at about 175° Centigrade during from four to five hours or until the
contents of the vessel solidify into a crystalline melt possessing a dark green
metallic appearance and dissolving in Alcohol with a rich crimson color. Throughout
this operation the access of air which would otherwise tend to deteriorate the product
ought to be prevented as much as possible.
The melt thus produced is then allowed to cool and reduced to powder. Its principal
constituent is the Phthalate of the new coloring matter which may be obtained in a
pure and well crystallized condition by dissolving the melt in boiling Alcohol and by
setting the solution aside to crystallize.
As however the said Phthalate is almost insoluble in water and therefore necessitates
the use of Alcohol as a solvent for dyeing purposes the colouring matter ought by
preference to be converted into the more convenient mercantile form of a hydro-
chlorate or other saline compound which is capable of dissolving in water. For the
said purpose the finely powdered melt produced as above described is agitated during
several hours with weak Caustic Ammonia and the base of the colouring matter thus
set free is afterwards extracted by repeated shakings with Benzine or other suitable
solvent. From the Benzolic extracts thus obtained the desired saline compound (say
for instance the before named hydrochlorate) may then be withdrawn by agitation
with the requisite amount of hot and dilute hydrochloric acid. The aqueous solutions
are separated from the supernatant layer of benzine and allowed to cool, and the said
hydrochlorate of the colouring matter will then be deposited in small glittering
crystals.
The before described conversion of the phthalate into the base, and subsequently
into the hydrochlorate or other soluble salt of the same may be varied to a great
extent by the employment of other suitable methods, known or in use for effecting
similar conversions of one saline compound into another, and by taking into account
the chief properties of the colouring matter hereinafter to be described.
The said chief properties of the colouring matter are the following
The chemical composition of the free Rhodamine-base (dried at 100° Centigrade)
corresponds to the formula:
TL:
مط
C20 H1003 N2 Me
tommed.
-
Tatramathuvel ploduming " It has the

page_text: Improvements in the Manufacture or Production of Red Colouring
Matters suitable for Dyeing and Printing.
I JAMES YATE JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of this Invention which has been communi-
cated to me from abroad by the Badische Anilin and Soda Fabrik of Ludwigshafen-
on-the-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:-
This Invention relates to the manufacture or production of red colouring matters
suitable for Dyeing and Printing, they belonging to a new series of Phthaleines, which
result from the condensation of one molecule of phthalic anhydride or of its halogen-
substitution-products with two molecules of meta-amido-phenol or of its alkyl-
derivatives.
The said new series of Phthaleines comprises within itself a large number of colouring
matters, capable of producing various shades of Reds-ranging from a reddish-Yellow
to a reddish-Purple-in Dyeing and Printing and differing from the Phthaleines,
hitherto in use, by their basic character. To the entire group of colouring matters,
belonging to the said series of Phthaleines, the generic name of "Rhodamines" may
therefore hereinafter be applied.
The colouring matters, produced according to the present Invention, are alkylized
Rhodamines, produced by the condensation of one molecule of phthalic anhydride with
two molecules of dimethyl- or of dyethyl-meta-amidophenol.
The said methyl- or ethyl-derivatives of meta-amidophenol have I believe remained
hitherto unknown. They may be obtained from meta-amidophenol by an application
of the known or suitable methods of alkylizing amidocompounds. For instance, a
mixture of hydrochlorate of meta-amidophenol with methylic alcohol is heated in a
closed digester during about eight hours at a temperature of about one hundred and
seventy degrees Centigrade. The excess of methylic alcohol having been recovered by
distillation, the residuary hydrochlorate of di-methyl-meta-amidophenol is then
decomposed by carbonate of soda and the phenolic body, thus set free, is extracted
with ether. The ether is then distilled off, and the crude dimethyl-meta-amidophenol
thus obtained is purified by crystallization from boiling ligroine or from other suitable
solvents. In its pure state dimethyl-meta-amidophenol is a white crystalline solid,
fusing at eighty six degrees Centigrade.
In an analogous manner diethyl-meta-amidophenol may be obtained from meta-amido-
phenol by heating a mixture of the hydrochlorate of meta-amidophenol with ethylic
alcohol in a closed digester during about ten hours at a temperature of about onc
hundred and seventy degrees Centigrade. The excess of ethylic alcohol having been
recovered by distillation, the residuary hydrochlorate of crude diethyl-meta-amido-
phenol is then decomposed by carbonate of soda and the phenolic body, thus set free,
is extracted with ether. The ether is then distilled off, and the crude diethyl-meta-
amidophenol thus obtained is first purified by distillation in a current of carbonic acid
gas. A further purification is effected by dissolving the distillate in dilute acetic acid,

page_text: and ether. The solutions in the two latter solvents are colourless, but upon the
addition of a dilute mineral or organic acid the rich crimson colour of the corresponding
saline compounds of Tetramethyl-rhodamine thus formed, is immediately developed.
The alcoholic solution of the free base is red and strongly fluorescent.
The above named crystallised hydrochlorate of Tetramethyl-rhodamine contains
one molecule of hydrochoric acid. It is readily soluble in pure water with an intense
crimson colour, the diluted solution exhibits a brilliant orange-yellow fluorescence.
Hydrochloric acid, when added in small quantity to a moderately strong solution
quickly causes the colouring matter to separate out in small crystals, which when
suspended in the liquid, transmit the light with a purple or blue colour. A large
excess of strong hydrochloric acid turns the solution scarlety-red or orange.
Concentrated sulphuric acid dissolves the colouring matter with a yellow colour.
An aqueous solution of the Tetramethyl-rhodamine salts gets rapidly decolourized
upon being treated with caustic ammonia and zinc-dust in the cold, the colour
however immediately reappears, as soon as a drop of red prussiate of potash liquor is
added to the colourless solution.
Tetramethyl-rhodamine imparts very pure red tints or colours varying from pink
to crimson both to animal and vegetable textile fibre. Silk and wool are dyed without
the aid of a mordant in a dye-bath, either neutral or slightly acidulated with acetic
acid. The shades thus obtained rival those, which may be dyed with the brightest
and bluest varieties of the Eosine-class of Phthaleines, but they greatly surpass the
latter as far as regards resistance to air and light. Cotton, which has received a
tannin mordant, may be dyed with the colouring matter after the manner practised
for dyeing basic aniline-colours. The shades thus obtainable are somewhat bluer and
duller than those produced upon animal fibre.
In an analogous manner Tetraethyl-rhodamine and the salts thereof may be produced
by the condensation of one molecule of phthalic-anhydride with two molecules of the
above-described diethyl-meta-amidophenol. The properties of the colouring matter
thus produced are very similar to those of the tetramethyl rhodamine hereinbefore
described, some differences however exist, of which the following may here be shortly
noticed:
The free base of tetraethyl-rhodamine is soluble in water and also considerably
more soluble in benzene than is its lower homologue. From a hot solution in ligroine
the tetraethyl-rhodamine-baso is deposited upon cooling in a crystalline or flocculent
condition, colourless or slightly pink-coloured, but upon the addition of a dilute mineral
or organic acid the rich crimson colour of the respective saline compounds is imme-
diately developed. This crimson colour is of a more bluish hue than the tint of the
corresponding solutions of Tetramethyl-rhodamine. The same differences may be
observed in comparing the shades dyed or printed with Tetraethyl-rhodamine and
Tetramethyl-rhodamine respectively. The former are generally of a more blueish
cast than the latter.
The above described condensation of the alkyl derivatives of meta-amidophenol
may likewise be effected by employing phthalic acid in lieu of phthalic anhydride,
and by operating with the aid of dehydrating or so called condensing agents, such for
instance as chloride of zinc, but so far decidedly the best results have been obtained
by proceeding in the manner hereinbefore described.

page_text: and by fractionally precipitating the solution thus obtained with carbonate of soda.
At first the impurities are precipitated, and then a further addition of the precipitant
separates oily drops, which, upon being placed in contact with a small fragment of
crystallised diethyl-meta-amidophenol, solidify into a white crystalline mass of the
purified product. By a final crystallization from a mixture of sulphide of carbon and
petroleum, or from other suitable solvents, diethyl-meta-amidophenol may be obtained
in well defined compact crystals, fusing at seventy four degrees Centigrade.
The following is an example of the manner in which the above named dimethyl-
meta-amidophenol may be condensed with phthalic anhydride in order to produce the
correspondingly alkylized rhodamine.
An intimate mixture of about ten parts by weight of dimethyl-meta-amidophenol
with about twelve parts by weight of phthalic anhydride is heated in an enamelled
digester, provided with an agitator and fitted up within an oil-bath, the temperature of
which is kept at about one hundred and seventy five degrees Centigrade during from
four to five hours, or until the contents of the vessel solidify into a crystalline melt,
possessing a dark green metallic appearance and dissolving in alcohol with a rich
crimson colour. Throughout this operation the access of air, which would otherwise
tend to deteriorate the product, ought to be prevented as much as possible.
The melt, thus produced, is then allowed to cool and reduced to powder. Its
principal constitutent is the phthalate of the new colouring matter, which may be
obtained in a pure and well crystallized condition by dissolving the melt in boiling
alcohol and by setting the solution aside to crystallize.
As however the said phthalate is almost insoluble in water and therefore necessitates
the use of alcohol as a solvent for dyeing purposes, the colouring matter ought by
preference to be converted into the more convenient mercantile form of a hydrochlorate
or other saline compound, which is capable of dissolving in water. For the said
purpose the finely powdered melt, produced as above described, is agitated during
several hours with weak caustic ammonia, and the base of the colouring matter, thus
set free, is afterwards extracted by repeated shakings with benzene or other suitable
solvent. From the benzolic extracts thus obtained the desired saline compound (say
for instance the before named hydrochlorate) may then he withdrawn by agitation with
the requisite amount of hot and dilute hydrochloric acid. The aqueous solutions are
separated from the supernatant layer of benzene and allowed to cool, and the said
hydrochlorate of the colouring matter will then be deposited in small glittering
crystals.
The before-described conversion of the phthalate into the base, and subsequently
into the hydrochlorate or other soluble salt of the same, may be varied to a great
extent by the employment of other suitable methods, known or in use for effecting
similar conversions of one saline compound into another, and by taking into account
the chief properties of the colouring matter, hereinafter to be described.
The said chief properties of the colouring matter are the following:
The chemical composition of the free Rhodamine-base (dried at 100° C.) corresponds
to the formula:
This compound may therefore be termed "Tetramethyl-rhodamine." It has the
character of an aromatic amine, capable of forming mostly well defined and crystallis-
able salts with mineral and organic acids, from the solutions of which it can be
separated in a crystallized condition by the addition of caustic alkalies or ammonia.
It is almost insoluble in cold water, but readily soluble in alcohol, and less so in
benzene and ether. The solutions in the two latter solvents are colourless, but upon
the addition of a dilute mineral or organic acid the rich crimson colour of the corre-
sponding saline compounds of Tetramethyl-rhodamine, thus formed, is immediately
developed. The alcoholic solution of the free base is red and strongly fluorescent.
The above named crystallized hydrochlorate of Tetramethyl-rhodamine contains
one molecule of hydrochloric acid. It is readily soluble in pure water with an intense

page_text: crimson colour, the diluted solution exhibits a brilliant orange-yellow fluorescence.
Hydrochloric acid, when added in small quantity to a moderately strong solution,
quickly causes the colouring matter to separate out in small crystals, which, when
suspended in the liquid, transmit the light with a purple or blue colour. A large
excess of strong hydrochloric acid turns the solution scarlety-red or orange.
Concentrated sulphuric acid dissolves the colouring matter with a yellow colour.
An aqueous solution of the Tetramethyl-rhodamine salts becomes rapidly
decolourized upon being treated with caustic ammonia and zinc-dust in the cold,
the colour however immediately reappears, as soon as a drop of red prussiate of
potash liquor is added to the colourless solution.
Tetramethyl-rhodamine imparts very pure red tints or colours-varying from pink
to crimson both to animal and vegetable textile fibre. Silk and wool are dyed with-
out the aid of a mordant in a dye-bath, either neutral or slightly acidulated with
acetic acid. The shades thus obtained rival those, which may be dyed with the
brightest and bluest varieties of the Eosine-class of Phthaleines, but they greatly
surpass the latter as far as regards resistance to air and light. Cotton, which has
received a tannin mordant, may be dyed with the colouring matter after the manner
practised for dyeing basic aniline-colours. The shades thus obtainable are somewhat
bluer and duller than those produced upon animal fibre.
In an analogous manner Tetraethyl-rhodamine and the salts thereof may ho
produced by the condensation of one molecule of phthalic-anhydride with two
molecules of the above described diethyl-meta-amidophenol. The properties of the
colouring matter thus produced are very similar to those of the tetramethyl-rhodamine
herein before described, some differences however exist, of which the following may
here be shortly noticed.
The free base of tetraethyl-rhodamine is soluble in water and also consider-
ably more soluble in benzene than is its lower homologue. From a hot solution in
ligroine the tetraethyl-rhodamine-base is deposited upon cooling in a crystalline or
flocculent condition, colourless or slightly pink-coloured, but upon the addition of a
dilute mineral or organic acid the rich crimson colour of the respective saline compounds
is immediately developed. This crimson colour is of a more blueish hue than the tint
of the corresponding solutions of Tetramethyl-rhodamine. The same differences may
be observed in comparing the shades dyed or printed with Tetraethyl-rhodamine and
Tetramethyl-rhodamine respectively. The former are generally of a more blueish
cast than the latter.
The above described condensation of the alkyl-derivatives of meta-amidophenol may
likewise be effected by employing phthalic acid in lieu of phthalic anhydride, and by
operating with the aid of dehydrating or so-called condensing agents, such for instance
as chloride of zinc, but so far decidedly the best results have been obtained by
proceeding in the manner herein before described.
Having now described and ascertained the nature of the said invention and
in what manner the same is to be performed I declare that what I claim is :-
First. The preparation of Dimethyl- and of Diethyl-meta-amidophenol by methyl-
izing or ethylizing Meta-amidophenol substantially in the manner and for the purpose
herein before described.
Second. The preparation of Tetramethyl-rhodamine and of Tetraethylrhodamine by
the condensation of phthalic anhydride with the above named dimethyl- or diethyl-
meta-amidophenol, substantially in the manner hereinbefore described.