Improvements in the Manufacture of Chloro-para-oxy-benzoic Acids.
Year: 1892

page_text: Date of Application, 26th Sept., 1892
Complete Specification Left, 9th June, 1893-Accepted, 22nd July, 1893
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Chloro-para-oxy-benzoic Acids.
I BENJAMIN WILLCOX of 47 Lincolns Inn Fields in the County of Middlesex
Patent Agent do hereby declare the nature of this invention (which has been
communicated to me from abroad by Dr. F. von Heyden, Nachfolger of Radebeul
near Dresden in the Empire of Germany) to be as follows:-
:-
This invention relates to the manufacture of mono-chloro-para-oxybenzoic acids
and dichloro-para-oxy-benzoic acid by causing one or two molecular proportions of
chlorine to act upon one molecular proportion of para-oxybenzoic acid as
hereinafter set forth.
A practical, that is to say, a cheap and easy method for manufacturing mono-
and di-chloro-para-oxy benzoic acid has not heretofore been known,
In the "Journal für Praktische Chemie" v. 13 p. 432 Lössner states that he
obtained these two acids by melting together para-oxy-benzoic acid and penta-
chloride of antimony.
"
According to Peltzer ("Annalen v. 146 p. 286) mono-chloro-para-oxybenzoic
acid can be obtained by causing chlorine gas to act upon the dry silver salt of
para-oxy-benzoic acid.
The action of chlorine upon free para-oxy-benzoic acid has heretofore been
considered an inconvenient method of obtaining chloro-para-oxy-benzoic acids.
Peltzer for example in the "Annalen v. 146 p. 285 makes the following
statement.
"
"By the direct action of chlorine upon free para-oxy-benzoic acid especially as
it must take place in sunlight or at an elevated temperature a mixture is probably
obtained of different highly chlorinated products along with unchanged para-oxy-
benzoic acid from which the pure bodies can be separated only with great difficulty
and with considerable loss."
Contrarily to the foregoing statements my foreign correspondent has discovered
that free para-oxy-benzoic acid can be easily and gently converted by chlorine
first into mono-para-oxy-benzoic acid and afterwards into di-chloro-para-oxy-
benzoic acid and that this method is well adapted for practical working.
In working this process it is advantageous to mix the para-oxy-benzoic acid with
a neutral liquid such as acetic acid sulphuret of carbon or the like.
It is immaterial whether free chlorine be employed or chlorine yielding materials
such as hydrochloric acid and chlorates, hydrochloric acid and subchlorides and
the like.
The following are given as examples of the process of manufacture according to
this invention the parts being he weight
EXAMPLE 1.
To a mixture of 414 parts of para-oxy-benzoic acid, 600 parts of acetic acid
and 380 parts of concentrated hydrochloric acid, 122.5 parts of potassium chlorate
are gradually added care being taken to prevent the temperature from rising above
90 degrees centigrade.
The resulting solution is diluted with about three times the quantity of water
and takes the form of a crystalline paste of mono-chloro-para-oxy benzoic acid
which is filtered and washed. It melts at 169 degrees centigrade. The amount
actually obtained is almost equal to the amount theoretically obtainable.

page_text: To 138 parts of para-oxy benzoic acid, 200 parts of acetic acid are added and
then 71 parts of chlorine are introduced. The subsequent operations are the same
as in Example 1.
Di-chloro-para-oxy-benzoic acid is obtained in like manner when the quantity of
chlorine or chlorine yielding material is doubled.
These chloro-para-oxy-benzoic acids are applicable to the production of pyro-
catechin and pyrogallol in the same way as is the bromo-para-oxy-benzoic acids
described in the Specification of Letters Patent No. 5184 of 1891.
Dated this 26th day of September 1892.
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, Agents.
'
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Chloro-para-oxy-benzoic Acids.
I BENJAMIN WILLCOX of 47 Lincoln's Inn Fields in the County of Middlesex,
Patent Agent do hereby declare the nature of this invention (which has been
communicated to me from abroad by Dr. F. von Heyden Nachfolger of Radebeul
near Dresden 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 of mono-chloro-para-oxy-benzoic acid
and dichloro-para-oxy-benzoic acid by causing one molecular proportion or two
molecular proportions of chlorine to act upon one molecular proportion of para-oxy-
benzoic acid as hereinafter set forth.
A cheap easy and practical process of manufacturing mono-chloro-para-oxy-
benzoic acid and di-chloro-para-oxy-benzoic acid has not heretofore been known.
In the "Journal für Praktische Chemie" vol. 13 page 432, Lössner states that
he obtained these two acids by melting together para-oxy-benzoic acid and penta-
chloride of autimony.
According to Peltzer ("Annalen "vol. 146 page 286) mono-chloro-para-oxy-
benzoic acid can be obtained by causing chlorine gas to act upon the dry silver salt
of para-oxy-benzoic acid.
The action of chlorine upon free para-oxy-benzoic acid has heretofore been
considered an inconvenient method of obtaining chloro-para-oxy-benzoic acids.
Peltzer for example in the "Annalen" vol. 146 page 285 makes the following
statement (which is here translated from the original German).
"By the direct action of chlorine upon free para-oxy-benzoic-acid especially
as it must take place in sunlight or at an elevated temperature a mixture is
probably obtained of different highly chlorinated products along with unchanged
para-oxy-benzoic acid from which the pure bodies can be separated only with great
difficulty and with considerable loss."
Contrarily to the foregoing statements my foreign correspondent has discovered
that free para-oxy-benzoic acid can be easily and gently converted by chlorine first
into mono-chloro-para-oxy-benzoic acid and afterwards into di-chloro-para-oxy-
benzoic acid and that this method is well adapted for practical working.
In working this process it is advantageous to mix the para-oxy-benzoic acid
with an indifferent liquid such as acetic acid, sulphuret of carbon or the like.
It is immaterial whether in the process there be employed free chlorine or chlorine
yielding materials such as hydrochloric acid and chlorates or hydrochloric acid and
subchlorides or the like.
The following are given as examples of the process of manufacture according to
this invention the parts being by weight.

page_text: EXAMPLE 1.
To a mixture of 414 parts of para-oxy-benzoic acid 600 parts of acetic acid
and 380 parts of concentrated hydrochloric acid there are gradually added 122-5 parts
of potassium chlorate care being taken to prevent the temperature from rising above
90 degrees centigrade.
The resulting solution is diluted with about three times the quantity of water
and takes the form of a crystalline paste of mono-chloro-para-oxy-benzoic acid
which is filtered and washed. It melts at 169 degrees centigrade. The amount
actually obtained is almost equal to the amount theoretically obtainable.
so degrees centigrade.
The resulting solution is diluted with about three times the quantity of water
and takes the form of a crystalline paste of mono-chloro-para-oxy-benzoic acid
which is filtered and washed. It melts at 169 degrees centigrade. The amount
actually obtained is almost equal to the amount theoretically obtainable.
EXAMPLE 2.
To 138 parts of para-oxy-benzoic acid 200 parts of acetic acid are added and
then 71 parts of chlorine are introduced. The subsequent operations are the same
as in Example 1.
Di-chloro-para-oxy-benzoic acid is obtained in like manner when the quantity of
chlorine or chlorine yielding material is doubled.
These chloro-para-oxy-benzoic acids are applicable to the production of pyro-
catechin and pyro-gallol in the same way as are the bromo-para-oxy-benzoic acids
described in the Specification of Letters Patent No. 5184 of 1891.
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 mono-chloro-para-oxy-benzoic acid and of di-chloro-para-
oxybenzoic acid by the action respectively of one molecular proportion and two
molecular proportions of chlorine (either free chlorine or in the form of chlorine
yielding materials such for example as hydrochloric acid and a chlorate or sub-
chloride) upon one molecular proportion of para-oxybenzoic acid substantially as
hereinbefore explained.
2. The manufacture of either mono-chloro-para oxybenzoic acid or of di-chloro-
para-oxy benzoic acid in the manners hereinbefore set forth with reference to the
two examples given.
Dated this 9th day of June 1893
J. H. JOHNSON & Co.,
Agents.