The Manufacture or Production of Acetyl Salicylic Acid.
Year: 1898

page_text: Date of Application, 22nd Dec., 1898
Complete Specification Left, 15th Sept., 1899-Accepted, 4th Nov., 1899
[Communicated from abroad by THE FARBENFABRIKEN VORMALS, FRIEDRICH
BAYER & Co., of Elberfeld, Germany.]
The Manufacture or Production of Acetyl Salicylic Acid.
I, HENRY EDWARD NEWTON, of the Office for Patents, 6, Bream's Buildings
Chancery Lane, in the County of London, Patent Agent, do hereby declare the
nature of this invention to be as follows:-
In the Annalen der Chemie und Pharmacie, Vol. 150, pp. 11 and 12, Kraut has
described that he obtained by the action of acetyl-chloride on salicylic acid, a body
which he thought to be acetyl-salicylic acid.
My foreign correspondents have now found that on heating salicylic acid with
acetic anhydride, a body is obtained, the properties of which are perfectly different
from those of the body described by Kraut.
According to the researches of my foreign correspondents, the body obtained by
them is undoubtedly the real acetyl salicylic acid→
but is another compound.
In the following description, the principal differences between the new compound
(which may be denoted by A), and the body described by Kraut (which is termed B),
are pointed out specifically.
If the compound B is boiled, even for a long while, with water (according to Kraut's
statement), acetic acid is not produced, whilst the new body A, when boiled with
water, is readily split up, acetic and salicylic acid being produced. The watery
solution of the body B shews the same behaviour, on the addition of a small
quantity of ferric chloride, as a watery solution of salcylic acid when mixed with
a small quantity of ferric chloride, that is to say, it assumes a violet colour.
On the contrary, a watery solution of the new body A, when mixed with ferric
chloride, does not assume a violet,colour.
If a melted test portion of the body B is allowed to cool, it begins to solidify
(according to Kraut's statement) at from 118 to 118.5 degrees Centigrade, whilst a
inelted test portion of A solidifies at about 70 degrees Centigrade. The inelting points
of the two compounds cannot be compared, because Kraut does not mention the
melting point of his compound.
It follows from these details, that the two compounds A and B are absolutely
different.
In order to illustrate the production of their new compound, my foreign cor-
respondents give the following example A, the parts being by weight.—

page_text: A mixture prepared from 50 parts of salicylic acid and 75 parts of acetic anhydride,
is heated for about two hours, at about 150 degrees Centigrade, in a vessel provided
with a reflux condensor. Thus, a clear liquid is obtained, from which, on cooling, a
crystalline mass is separated, which is the acetyl salicylic acid. It is freed froin the
acetic anhydride by pressing, and is then recrystallized from dry chloroform. The
acid is thus obtained in the shape of glittering white needles, melting at about
135° Centigrade, which are readily soluble in benzene, alcohol, glacial acetic acid, and
chloroform, but with difficulty in cold water.
It has the formula
and exhibits therapeutical properties.
My foreign correspondents have further found, that if acetyl-chloride is caused to
act on salicylic acid, not the body described by Kraut (1.c.), but likewise the acetyl
salicylic acid herein before described, is obtained.
In order to illustrate this method of proceeding, the following example B is given,
the parts being by weight.-
EXAMPLE B.
25 parts of salicylic acid are mixed with 20 parts of acetyl chloride, and then heated
for several hours, at about 80° Centigrade, in a vessel provided with a reflux
condenser. Subsequently the excess of acetyl chloride is distilled off with the aid of
a water bath. The so-produced white crystallized mass is recrystallized from dry
chloroform.
The product thus obtained is identical with that described in example A.
My foreign correspondents wish it to be understood that they do not intend to
confine themselves to the particulars given in the foregoing specification, as these
can be varied within wide limits. Thus, for instance, instead of the free salicylic
acid, the salts of this acid can also be employed. Instead of being performed
in open vessels, the reactions herein before described can also be carried out in auto-
claves.
Such or the like variations do not alter the nature of the present invention.
I, HENRY EDWARD NEWTON, of the Office for Patents, 6, Bream's Buildings,
Chancery Lane, in the County of London, Patent Agent, 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 :-
In the "Annalen der Chemie und Pharmacie," Vol. 150, pp 11 and 12, Kraut bas
described that he obtained, by the action of acetyl chloride on salicylic acid, a body
which he thought to be acetyl salicylic acid.
My foreign correspondents have now found that on heating salicylic acid with

page_text: acetic anhydride, a body is obtained, the properties of which are entirely different
from those of the body described by Kraut.
According to the researches of my foreign correspondents, the body obtained by
them is undoubtedly the real acetyl salicylic acid :—
and exhibits therapeutic properties.
My foreign correspondents have further found that, if acetyl chloride is caused to
act on solicylic acid, not the body described by Kraut, as above mentioned, but the
acetyl salicylic acid herein before described is obtained.
In order to illustrate this method of proceeding the following example B, is given,
the parts being by weight.

page_text: Subsequently the excess of acetyl chloride is distilled off with the aid of a water bath.
The so produced white chrystalline mass is recrystallized from dry chloroform.
The product thus obtained is identical with that described in example A.
My foreign correspondents wish it to be understood that they do not intend to
confine themselves to the particulars given in the foregoing specification, as these
can be varied within wide limits. Thus, for instance, instead of the free salicylic
acid, the salts of this acid can also be employed. Instead of being performed in open
vessels, the reactions herein before described can also be carried out in autoclaves.
Such or the like variations do not alter the nature of the present invention.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed (as communicated to me
from abroad), I declare that what I claim is :-
1. The process for producing acetyl salicylic acid by causing acetic anhydride to
act on salicylic acid or its salts, substantially as herein before described.
2. For the production of acetyl salicylic acid, the use of the process which consists
in allowing acetyl chloride to act on salicylic acid or its salts, substantially as herein-
before described.
3. As a new article of manufacture, the new body herein before described.
4. The use of the new body hereinbefore described for therapeutic purposes.
Dated this 15th day of Contraban 1000
NEWTON & SON,
Agents for the Applicant.