The Manufacture and Production from Phthalonic Acid of Products related to the Rhodamine Series,
Year: 1895

page_text: Date of Application, 24th July, 1895
Complete Specification Lefr, 20th Feb., 1896-Accepted, 28th Mar., 1836
PROVISIONAL SPECIFICATION.
The Manufacture and Production from Phthalonic Acid of Products
related to the Rhodamine Series,
I JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of London
Gentleman do hereby declare the nature of this invention (which has been communi-
cated to me from abroad by The Badische Anilin & Soda Fabrik of Ludwigshafen
on Rhine in the Empire of Germany) to be as follows:-
This invention is based upon the discovery that the phtalonic acid obtained by
oxydizing naphthaline with potassium permanganate according to the process
described in the Specification of German Patent No. 79693 can be condensed with
alkylated meta amidophenols for forming rhodamines.
On heating a mixture of the phtalonic acid and dialkylated meta-amido-phenol,
say one molecular proportion of the former with two to three molecular proportions
of the latter, at a moderate temperature, for instance one hundred or one hundred
and ten degrees Centigrade colourless or nearly colourless intermediate products are
obtained. These products differ from the intermediate products formed in the
usual rhodamine melt from phtalic acid. So the intermediate product obtained from
phtalonic acid and di-ethyl-meta-amido-phenol is a crystalline powder which dis-
solves but sparingly in water, very difficultly in alcohol and readily in glacial
acetic acid, and also in diluted hydrochloric acid, or dilute alkalies or carbonates,
and melts at a temperature of about one hundred and seventy five degrees Centi-
grade, whilst the intermediate product from phtalic acid and diethyl-meta-amido-
phenol is rather more readily soluble in alcohol but is nearly uusoluble in diluted
hydrochloric acid, and melts at a temperature of about one hundred and ninety five
degrees Centigrade.
By heating these intermediate products to a higher temperature with or without
the aid of a condensing agent they are transformed into the rhodamine dyes. Of
course the formation of the intermediate products and their conversion into the
dyestuff may be effected in one operation by heating phtalonic acid and the alkylated
meta-amido-phenol to a bigher temperature with or without the addition of a
suitable condensing agent.
is
My foreign correspondents have further discovered that the conversion of the
above described new intermediate products into the dyestuffs can also be effected by
treating them with oxydizing agents. For instance tetra-ethyl rhodamine
obtained on heating the acetic or dilute sulphuric solution of the intermediate
product from phtalonic acid and diethyl-meta amido-phenol with ferric chloride.
In this reaction intermediate products having characteristic properties are observable
so that it is advisable to continue heating during some hours.
Instead of the said ferric chloride, manganese dioxide or persulphates can be used
as oxydizing agents and others such as chromic acid, sodium peroxide and the like
act in a similar way. Some of these agents require great precaution as an excess
of them will attack the dyestuff formed.
The following examples will serve to further illustrate the nature of the invention
but they are merely to be regarded as typical and their details can be varied in
many respects. The parts are by weight.

page_text: EXAMPLE L.
Heat a mixture of ten parts of diethyl-meta-amido-phenol and twelve parts of
phtalonic acid in an enamelled vessel in the oil-bath to a temperature of about
one hundred and eighty degrees Centigrade for some hours and stir the mass until
it solidifies or nearly so. Then powder the melt; digest with ammonia in order to
obtain the rhodamine base, dissolve the latter in benzene for extracting with this
solvent and convert into the hydrochloric salt as usual.
In this example instead of diethyl-meta amido-phenol other alkylated meta-amido
phenols can be used.
EXAMPLE 11.
One hundred and seventy three parts of phtalonic acid and four hundred and
eighty two parts of dialkyl-meta-amido-phenol are mixed and heated for about
six hours to a temperature of about one hundred to one hundred and ten degrees Centi-
grade till the mass is solidified.
If it be desired to isolate in a purer condition the intermediate product formed
extract with boiling water, dissolve the residue in dilute hydrochloric acid
(containing about sixteen parts of real acid HCl) filter precipitate with a solution of
about ninety parts of crystallized sodium acetate, filter press and dry. Next
dissolve about fifty parts of the intermediate product (either in the crude state or
purified) in about seven hundred and fifty parts of diluted acetic acid (containing
about thirty per cent. real acid C2H4O2). To this solution add slowly about twenty
one parts of potassium persulphate, heat the mixture on the water bath for some
hours or until a test portion rendered alkaline with diluted soda-lye no longer shews
blue or violet colour, which by heating is converted into red. Then cool, precipitate
the dyestuff by the addition of common salt, filter and purify when necessary,
according to any known or suitable method.
Dated this 24th day of July 1895.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.
The Manufacture and Production from Phthalonic Acid of Products
related to the Rhodamine Series.
I, JAMES YATE JOHNSON, of 47 Lincoln's Inn Fields in the County of London,
Gentleman do hereby declare the nature of this invention (which has been commu-
nicated to me from abroad by The Badische Anilin & 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:
This invention is based upon the discovery that phthalonic acid (which can be
obtained by oxidizing naphthaline with potassium permanganate see Specification of
German Patent No. 79693) can be condensed with alkylated meta-amido-phenols
whereby finally rhodamines are obtained.
On heating a mixture of the phthalonic acid and dialkylated meta-amido-phenol
say one molecular proportion of the former with two to three molecular proportions
of the latter at a moderate temperature for instance one hundred or one hundred and
ten degrees Centigrade colourless or nearly colourless intermediate products are
obtained. These products differ from the intermediate products formed in the usual
rhodamine melt from phthalic acid. Thus the intermediate product obtained from

page_text: phthalonic acid and di-ethyl-meta-amido-phenol is a crystalline powder, which
dissolves but sparingly in water, very difficultly in alcohol, and readily in glacial
acetic acid, and also in diluted hydrochloric acid, or dilute alkalies, or carbonates,
and melts at a temperature of about one hundred and seventy five degrees Centigrade
whilst the intermediate product from phthalic acid and di-ethyl-meta-amido-phenol
is rather more readily soluble in alcohol but is nearly insoluble in diluted
hydrochloric acid and inelts at a temperature of about one hundred and ninety five
degrees Centigrade.
By heating these intermediate products to a higher temperature, with, or without,
the aid of a condensing agent, they are transformed into the rhodamine dyes.
Of course the formation of the intermediate products and their conversion into the
dyestuff may be effected in one operation by heating phthalonic acid and the
alkylated meta-amido-phenol to a higher temperature, with, or without, the addition
of a suitable condensing agent.
My foreign correspondents have further discovered that the conversion of the
above described new intermediate products into the dyestuffs can also be effected by
treating them with oxidizing agents. For instance tetra-ethyl-rhodamine is obtained
on heating the acetic or dilute sulphuric solution of the intermediate product from
phthalonic acid and di-ethyl-meta-amido-phenol with ferric chloride. In this reaction
intermediate products having characteristic properties are formed and it is advisable
to continue heating during some hours.
Instead of the said ferric chloride manganese dioxide or persulphates can be used
as oxidizing agents and others such as chromic acid, sodium peroxide and the like
act in a similar way. The oxidation requires great precaution as an excess of the
agent may readily attack the dyestuff formed.
The following examples will serve to further illustrate the nature of the invention
and the manner in which it can be carried into practical effect but they are merely
to be regarded as typical and their details can be varied in many respects. The
Twenty parts of phthalonic acid and about fifty parts of dialkyl-meta-amido-phenol
are mixed and heated for about six hours to a temperature of about one hundred to
one hundred and ten degrees Centigrade, till the mass is solidified. If it be desired to
isolate the intermediate product formed extract with boiling water, dissolve the residue
in dilute hydrochloric acid (containing about sixteen parts of real acid HCI), filter,
precipitate with a solution of about ninety parts of crystallized sodium acetate, filter,
press and dry. Next dissolve about fifty parts of the intermediate product (either
in the crude state or purified) in about seven hundred and fifty parts of diluted
acetic acid (containing about thirty per cent. real acid (₂HO₂). To this solution
add slowly twenty one parts of potassium persulphate heat the mixture on the water-
bath for some hours or until a test portion rendered alkaline with diluted soda-lye,
no longer shews blue or violet, which by heating the said portion is converted into
red. Then cool, precipitate the dyestuff by the addition of common salt, filter and
purify when necessary according to any known or suitable method.

page_text: 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 new intermediate products related to the rhodamine series
by treating phthalonic acid with an alkylated meta-amido-phenol substantially as
herein before described.
2. The manufacture of dyes of the rhodamine series by the action of heat with or
without the presence of a condensing agent on the intermediate products herein-
before described and claimed under the first claiming clause.
3. The manufacture of dyes of the rhodamine series by treating the intermediate
products hereinbefore described and claimed in the first claiming clause with an
oxidizing agent substantially as hereinbefore described.
4. The manufacture of dyes of the rhodamine series by first condensing phthalonic
acid with an alkylated meta-amido-phenol then converting the intermediate
compounds so obtained, whether isolated or not, into rhodamines by further heating,
with, or without, the addition of a condensing agent; substantially as hereinbefore
described.
5. The manufacture of dyes of the rhodamine series by first preparing the inter-
mediate products hereinbefore described and claimed in the first claiming clause, then
treating them, whether isolated or not, with an oxidizing agent all substantially as
hereinbefore described.
6. The manufacture of the new intermediate products and of the rhodamine dyes
in the manners herein described in the examples.
7. As new articles of manufacture the intermediate products hereinbefore
described such as can be obtained substantially as bereinbefore described.
Dated this 20th day of February 1896.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.