A New or Improved Process for Manufacturing Oxy-phenoxacetic Acids.
Year: 1896

page_text: Date of Application, 17th Dec., 1896-Accepted, 20th Feb., 1897
COMPLETE SPECIFICATION..
A New or Improved Process for Manufacturing Oxy-phenoxacetic
Acids.
I, Dr. LEONHARD LEDERER of 76 Gabelsbergerstrasse, Munich, in the German
Empire, 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 :-
Oxy-phenoxacetic acids and their homologues are reduced into phenols, either by
being heated with concentrated hydrochloric acid, or by being dissolved with
alkalies; the radical CH2COOH being at the same time eliminated. The same
remark applies to phenoxacetic acids.
The action of a halogenous hydracid upon alcoxylated (alcoxyles) phenoxacetic
acids is totally different, however, where the ordinary temperature or a moderate
heat prevails. In this case the radical CH2COOH remains remarkably intact,
while the alkyl-series, which displays greater stability as a rule, is, in a very neat
manner, entirely eliminated. There are therefore produced oxyphenoxacetic acids,
which possess excellent curative properties.
DESCRIPTION OF PROCESS.
(1) By means of a slow current of bromhydric acid a certain amount of
hydrated guaiacoxacetic acid is washed. With the bromhydric acid in excess
there escapes a gas which having the property of burning with a green flame, is
readily recognizable as methyl bromide. A re-action takes place even while the
re-agents are cold, but is accentuated when slightly heated. After cooling the
whole mass crystallizes, and by re-crystallizing it out, of water, oxyphenoxacetic
acid is obtained in a pure condition (as pyrocatechinacetic acid).
(2) One part of guaiacoxacetic acid and three parts of concentrated hydro-
chloric acid are heated for a number of hours to a temperature of 100° Centigrade
in a closed receiver. Alter cooling, the product, viz., oxyphenoxacetic acid,
separates, partly crystallized from the clear solution, which is slightly tinged red,
while the remainder may be removed by the aid of ether.
Oxyphenoxacetic (pyrocatechinacetic) acid very readily dissolves in hot water
and separates therefrom by cooling in large brittle tablets fusible at 139° Centrigrade,
while part of it becomes converted into anhydride. Its aqueous solution, in
conjunction with iron chloride will assume a dark blue tint. Dry distillation will
cause oxyphenoxacetic acid to instantly transform into anhydrides. This anhydride,
whose fusing point is at 58° Centigrade, has, whilst hot, an odour of bitter almond
essence, and may be distilled without decomposition. When dissolved in water it
again becomes converted into acid.
(3) Moist eugenoxacetic acid is acted upon by bromhydric acid vapours. The
material under treatment melts, and along with the bromhydric acid vapours,
bromethyl is given off. The re-action is interrupted as soon as bromethyl ceases from
being given off. The oleaginous product of the re-action is washed with water for the
purpose of eliminating the bromhydric acid, of which it contains an admixture, and
is then treated with ether or benzol. After the elimination of the solvent, there
remains bromine propyloxyphenoxacetic acid. This acid produced by the separation

page_text: of the methyl group or series, and owing to the simultaneous addition of bromhydric
acid, forms in accordance with the following formula :-
C'H (CH) (OCH³) OCH³O.COOH + 2 HBr =
CH³ (C'H Br) (OH) OCH³O.COOH + CH³Br.
thin white crystals which melt at 75° Centigrade (or, when cooled after the
fusing test, at 82°) and decompose at 100° Centigrade, giving off a certain amount
of gas at the same time. Boiling with a sodic solution or, indeed, simply with
water, will entirely eliminate the bromine in a short time. The separation of
eugenoxacetic acid by means of a hydro-chlorate takes place in the same way,
as, in this case also, there forms a precipitate of hydrochloric acid, while chlorine-
propyloxyphenoxacetic acid is produced, whose fusing point is at 70° Centigrade,
and whose properties are identical with those of the bromine derivative.
The alcoholic solutions of the halogen acids, like those of non-halogen acids,
colour a pronounced green, when aqueous ferric chloride is added to them.
(4) One part of eugenoxacetic acid and two parts of concentrated hydrochloric
acid are heated for from 1 to 2 hours in a closed vessel. The product of the
re-action is set free in the manner already stated with reference to Example 3.
In the same way mixtures of phenoxacetic acids and alcoxylated phenoxacetic
acids may be treated. Oxyphenoxacetic acids may be readily separated from the
phenoxacetic acids owing to their solubility in water.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is-
A process for the manufacture of oxyphenoxacetic acids, consisting in treating
alcoxyl-phenoxacetic acids at the ordinary temperature or under the action of heat
with halogen-hydracids, substantially as described.
ROBERT E. PHILLIPS, Assoc. M. Inst. C.E., M.I. Mech. E.,
Consulting Engineer and Patent Agent,
70, Chancery Lane, London, W.C., Associate Agent.