Process for Obtaining Pyrocatechin-monoacetic Acid.
Year: 1895

page_text: Date of Application, 14th Sept., 1895
Complete Specification Left, 26th Mar., 1896-Accepted, 2nd May, 1896
Process for Obtaining Pyrocatechin-monoacetic Acid.
1, WILHELM MAJERT, of Falkenberg near Grünau, in the Kingdom of Prussia
and German Empire, Chemist, do hereby declare the nature of this invention to be
as follows:-
Monoacetic acids of dibasic phenols are as yet believed to be unknown.
In the treatise of Auwers and Haymann, (Berichte 27-3, seite 2804), it is stated
that no pyrocatechin-monoacetic acid is produced by the action of chloro-acetic
acid ester upon pyrocatechinmononatrium. In fact, according to the process there
described, 87 gr. of pure unchanged pyrocatechin were recovered from 10 gr.
pyrocatechin.
of
A similar result was obtained by submitting dry pyrocatechiumonosodium
dissolved in xylol to the action of ethyl ester of chloro-acetic acid.
These results are the more surprising as, under the indicated conditions,
guaiacol and pyrocatechinmonoethylester are produced in good quantities from
pyrocatechinmonosodium and iodomethyl and bromethyl respectively, whilst the
chloro-acetic acid esters have chemical properties quite analogous with those of the
halogenalkyls relatively to the salts of the monobasic phenols.
The salts of the chloro-acetic acid are in quite a different relation to
pyrocatechinmonosodium as compared with the ether of chloro-acetic acid, and
give a good production of pyrocatechinmonoacetic acid.
Sodium pyrocatechinmonoacetate has already proved itself to be a pre-eminent
remedy for loss of appetite and phthisis, having many advantages over guaiacol
and guaiacol carbonate. It produces, in from 2 to 6 half gram doses per day, a
material increase of appetite in sufferers from phthisis as well as a general
improvement in the state of the patient's health, with a cessation of night-sweats
and a more nearly normal evening temperature, and in slight cases, a total
disappearance of tubercular bacilli.
Pyrocatechinmonoacetic acid is obtained according to this invention by submitting
one molecule of chloro-acetic acid to the action of one molecule of pyrocatechin in
the presence of a free alkali or alkaline carbonate.
I may employ the following process:-
8.25 kilos. of chloro-acetic acid and 11 kilos. of pyrocatechin are dissolved in
45 litres of water.
Into this solution, whilst boiling under an inverted condenser, there is poured
slowly, a solution of 8 kilos. of sodium hydroxide in 20 litres of water or a solution
of a corresponding quantity of sodium carbonate. The boiling is continued until
the solution is neutral.
After cooling, there separates a crop of crystals of sodium pyrocatechinmono-
acetate. The mother liquor is drawn off and the salt is purified by recrystallisation
in water.
The acid resulting from this salt, has the following composition

page_text: By overheating the acid however, it changes to its lactone,
Process for Obtaining Pyrocatechin-monoacetic Acid.
I, WILHELM MAJERT, of Falkenberg near Grünau in the Kingdom of Prussia
and German Empire, Chemist, do hereby declare the nature of this invention, and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
Monoacetic acids of dibasic phenols are, as yet, believed to be unknown.
In the treatise of Auwers & Haymann, (Berichte 27-3, seite 2804), it is stated
that no pyrocatechinmonoacetic acid is produced by the action of chloro-acetic
acid ester upon pyrocatechinmononatrium. In fact, according to the process there
described, 8-7 gr. of pure unchanged pyrocatechin were recovered from 10.0 gr. of
pyrocatechin.
A similar result was obtained by submitting dry pyrocatechinsodium dissolved
in xylol to the action of ethyl ester of chloro-acetic acid.
These results are the more surprising as, under the indicated conditions,
guaiacol and pyrocatechinmonoethylester are produced in good quantities from
pyrocatechinmonosodium and iodomethyl and bromethyl respectively, whilst the
chloro-acetic acid esters have chemical properties quite analogous with those of
the halogenalkyls relatively to the salts of the monobasic phenols.
The salts of chloro-acetic acid are in quite a different relation to pyrocatechin-
monosodium as compared with the ether of chloro-acetic acid, and give a good
production of pyrocatechinmonoacetic acid.
Sodium pyrocatechinmonoacetate has already proved itself to be a pre-eminent
remedy for loss of appetite and phthisis, having many advantages over guaiacol
and guaiacol carbonate. It produces, in 2 to 6 half-gramme doses per day, a
material increase of appetite in sufferers from phthisis, as well as a general
improvement in the patient's health, with a cessation of night sweats and a more
nearly normal temperature in the evening and, in slight cases, a total disappearance
of tubercular bacilli.
Pyrocatechinmonoacetic acid is obtained according to this invention, by submitting
one molecule of chloro-acetic acid to the action of one molecule of pyrocatechin in
the presence of a free alkali or alkaline carbonate.
In carrying out my invention I may employ the following process:-
8.25 kilos. of chloro-acetic acid and 110 kilos. of pyrocatechin are dissolved in
water.
Into this solution, whilst it is boiling under an inverted condenser, there is slowly
poured, a solution of 8.0 kilos. of sodium hydroxide in 20 litres of water, or a solution
of a corresponding molecular quantity of sodium carbonate. The boiling is then
continued until the solution is neutral.
After cooling, there separates a crop of crystals of sodium pyrocatechin-
monoacetate. The mother liquor is drawn off and the salt is purified by
re-crystallisation in water.

page_text: melting at about 56° C.
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 :-
The hereinbefore described process for the manufacture or production of
pyrocatechinmonoacetic acid, substantially as set forth.
Dated this 24th day of March A.D. 1896.
W. E. HEYS & SON,
Agents for the Applicant.