Improvements in the Manufacture of Coloring Matters.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Coloring Matters.
(A communication from abroad by LA SOCIÉTÉ CHIMIQUE DES USINES DU RHONE
anciennement GILLIARD P. MONNET ET CARTIER, of Lyons, France, Manu-
facturers.)
I, GEORGE BELOE ELLIS, of the Firm of J. C. Mewburn and Ellis, of 55 and 56,
Chancery Lane, in the County of London, Chartered Patent Agents, do hereby declare
the nature of this invention to be as follows:-
This invention relates to the manufacture of coloring matters belonging to the
series of rhodamine ethers or anisolines.
The rhodamine ethers or anisolines are formed from the corresponding rhodamines
by further alkylation under conditions whereby the new alkyl groups attach thein-
selves to oxygen in the parent substance. The alkylated bodies thus produced are
generally bluer in shade than the corresponding rhodamines; they are more soluble
in water and they possess greater affinity for fibre.
Monnet, who discovered this reaction in 1891, sought first of all to prepare the
potassium salt of the rhodamines (or the salts of other monovalent metals) by treat-
iment with caustic alkalics in aqueous solution. In the presence of water, however,
the salts of the rhodamines with metals appear to be more or less completely
dissociated into the free base.
Now according to the present invention which is based on a discovery of my foreign
correspondents, the potassium or corresponding metal salts of the rhodamines are
formed by treating the base with one molecular proportion of (say) potassium hydroxide
in a solution or vehicle in which dissociation of the potassium salt does not take place.
Alcohol has been found to be very suitable for the purpose.
In lieu of potassium hydroxide other caustic alkalies including ammonia may be
employed.
The salts thus formed are readily converted into the corresponding rhodamine ethers
or anisolines by heating with alkyl halogens at or below the temperature of the water
bath, and thus all danger of overheating is avoided.
The method is particularly serviceable for the conversion of the rhodamine bases
soluble with difficulty in alcohol, such as the symmetrical diethyl rhodamine base of
the phtalic acid series, as for example the potassium salt dissolves readily in alcohol.
It may be applied to all the symmetrical rhodamines, both di-alkylated and tetra
alkylated, as well as to the asymmetrical rhodamines, and both of the phtalic acid and
succinic acid series.
The following example shows how the process may be applied, but the quantities
and temperatures and duration of heating may be varied considerably in different
instances.
1
5 kg, of diethyl rhodamine base is suspended in 50 kg. alcohol containing 700 gr.,
caustic potash or the equivalent quantity of another alkali in solution; 5 kg. ethyl
chloride is added and the whole heated in an autoclave at water bath temperature for;
two or more hours.

page_text: The product is worked up in the usual way.
Instead of ethyl chloride the equivalent quantity of an alkyl bromide or iodide may
be employed or of another alkyl chloride, and if the alkyl halogen is not too volatile
instead of an antoclave an open vessel with return condenser may be employed,
In lieu of treating the base of the rhodamine, a commercial salt of the rhodamines,
for example the hydro-chlorate, may be treated, but in this case the amount of the
alkali employed should be appropriately increased, so that the alkali shall be present
in sufficient quantity to take off the hydrochloric acid and to form the metallic salt
of the rhodamine.
Dated this 80th day of March 1897
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London, Chartered Patent Agents.
Improvements in the Manufacture of Coloring Matters.
(A communication from abroad by LA SOCIÉTÉ CHIMIQUE DES USINES DU RHÔNE
anciennement GILLIARD P. MONNET ET CARTIER, of Lyons, France, Manu-
facturers.)
I, GEORGE BELOE ELLIS, of the Firm of J. C. Mewburn and Ellis, of 55 and 56,
Chancery Lane, in the County of London, Chartered Patent Agents, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following state-
ment
This invention relates to the manufacture of coloring matters belonging to the
series of rhodamine ethers or anisolines.
The rhodamine ethers or auisolines are formed from the corresponding rhodamines
by further alkylation under conditions whereby the new alkyl groups attach them-
selves to oxygen in the parent substance. The alkylated bodies thus produced are
generally bluer in shade than the corresponding rhodamines; they are more soluble
in water and they possess greater affinity for fibre.
Monnet; who discovered this reaction in 1891, sought first of all to prepare the
potassium salt of the rhodamines (or the salts of other monovalent metals) by treat-
ment with caustic alkalies in aqueous solution. In the presence of water, however,
the salts of the rhodamines with metals appear to be more or less completely dis-
sociated into the free base.
Now according to the present invention which is based on a discovery of my foreign
correspondents, the potassium or corresponding metal salts of the rhodamines are
formed by treating the base with one molecular proportion of (say) potassium
hydroxide in a solution or vehicle in which dissociation of the potassium salt does not
take place. Alcohol has been found to be very suitable for the purpose.
In lieu of potassium hydroxide other caustic alkalies may be employed.
The salts thus formed are readily converted into the corresponding rhodamine
ethers or anisolines by heating with alkyl halogens at or below the temperature of
the water bath, and thus all danger of overheating is avoided.
The method is particularly serviceable for the conversion of the rhodamine bases
soluble with difficulty in alcohol, such as the symmetrical diethyl rhodamine base of
the phtalic acid serica, as for example the potassium salt dissolves readily in alcohol.
It may be applied to all the symmetrical rhodamines, both di-alkylated and tetra
alkylated, as well as to the asymmetrical rhodamines, and both of the phtalio acid
and succinic acid series.
The following example shows how the process may be applied, but the quantities
and temperatures and duration of heating may be varied considerably in different
instances.

page_text: 5 kg. of diethyl rhodamino base is suspended in 50 kg. alcohol containing 700 gr.
caustic potash or the equivalent quantity of another alkali in solution; 5 kg. ethyl
chloride is added and the whole heated in an autoclave at water bath temperature for
two or more hours.
The product is worked up in the usual way.
Instead of ethyl chloride the equivalent quantity of an alkyl bromide or iodide may
be employed or of another alkyl chloride, and if the alkyl halogen is not too volatile
instead of an autoclave an open vessel with return condenser may be employed.
In lieu of treating the base of the rhodamine, a commercial salt of the rhodamines
for example the hydro-chlorate may be treated, but in this case the amount of the
alkali employed should be appropriately increased, so that the alkali shall be
present in sufficient quantity to take off the hydrochloric acid and to form the
metallic salt of the rhodamine.
Having now particularly described and ascertained the nature of the said invention
as communicated to me and in what manner the same is to be performed, I declare
that what I claim is:-
1. The manufacture of rhodamine ethers or anisolines by treating a rhodamine of
the phtalic or succinio series dissolved or suspended in alcohol with one molecular
proportion of caustic alkali and heating with excess of an alkyl halogen, substantially
as described.
2. The preparation of a metallic salt of a rhodainine, for example the potassium
salt of diethyl rhodamine, by suspending the rhodamine base in alcohol or other
indifferent medium and adding one molecular proportion of caustic alkali, sub-
stantially as described.
3. The manufacture of rhodamine ethers or anisolines by heating a metallic salt of
a rhodamine, for example, the potassium salt of diethylrhodamine, in alcoholic solution
with alkyl halogen, substantially as described.
4. The manufacture of coloring matters belonging to the series of rhodamine
ethers or anisolines, substantially as described.
Dated this 30th day of December 1897
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London, Chartered Patent Agents.