Improvements in the Manufacture of Salols.
Year: 1892

page_text: Date of Application, 20th Dec., 1892
D
Complete Specification Left, 6th Sept., 1893-Accepted, 20th Dec., 1893
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Salols.
I, HEINRICH BYк, M.D. of 35 Louisenstrasse, Berlin, in the Empire of
Germany, do hereby declare the nature of this invention to be as follows:-
Phosphorpentoxide is mixed with salicylic acid and heated in a stream of
carbonic acid gas. Or phosphorpentoxide or thick syrup of phosphoric acid
(having a specific weight of about 1·7) or a mixture of both, is heated in a stream
of carbonic acid gas, with salicylic acid and stirred until the commencement of the
sublimation of the salicylic acid takes place, whereupon phenole or napthole are
added.
For the formation of salole by the addition of phosphorpentoxide it suffices to
employ a further heating in the stream of carbonic acid gas at a temperature of
from 105° to 120° centigrade stirring being continued. In case thick syrup of
phosphoric acid is added it will be necessary to continue heating it in the stream
of carbonic acid gas several hours, keeping it well stirred. The phosphorpentoxide
and the thick syrup of phosphoric acid can as before stated be mixed direct with
the salicylic acid and resulting phenole and napthole, and afterwards heated as above
described.
As the meta-phosphoric acid is added the mixture of salicylic acid and the resulting
alcohols will liquefy with it in the stream of carbonic acid gas.
As one proceeds with the free salicylic acid, one also proceeds with its salts and
with the reaction mixture which is obtained by the formation of salicylic acid,
whereby one necessarily increases the quantity of the three phosphoric acids before
named, the effect of which is to deposit the metallic substances contained in the
salicylates.
Dated this 20th day of December 1892.
S. S. BROMHEAD,
97, Newgate Street, London, E.C., Agent for Applicant.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Salols.
I, HEINRICH BYк, M.D. of 35 Louisenstrasse, Berlin, in the Empire of
Germany, 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 my improved process for the production of salols, phosphorpentoxide is mixed
with salicylic acid and heated in a stream of carbonic acid gas. Or, phosphorpent-
oxide or thick syrup of phosphoric acid (having a specific weight of about 1:7) is
heated in a stream of carbonic acid gas, with salicylic acid and stirred until the
commencement of the sublimation of the salicyclic acid takes place, whereupon
phenol or napthol are added.
For the formation of salol by the addition of phosphorpentoxide it suffices to
employ a further heating in the stream of carbonic acid gas at a temperature of
from 105° to 120° centigrade, stirring being continued. In case thick syrup of
phosphoric acid is added it will be necessary to continue heating it in the stream
of carbonic acid gas several hours, keeping it well stirred. The phosphorpentoxide
and the thick syrup of phosphoric acid, can as before stated be mixed direct with
the salicylic acid and subsequently added phenol and napthol, and afterwards
heated as above described.

page_text: As the meta-phosphoric acid is added, the mixture of salicylic acid and the
subsequent alcohols will liquify with-it in the stream of carbonic acid gas.
As one proceeds with the free salicylic acid, one also proceeds with its salts and
with the reaction mixture which is obtained by the formation of salicylic acid,
whereby one necessarily increases the quantity of the three phosphoric acids before
named, the effect of which is to deposit the metallic substances contained in the
salicylates.
The actual chemical equivalent, is the quantity required of the reaction treating
ingredients, (salicylic acid, salicylates, phenols, napthols; phosphorpentoxide, meta-
phosphoric-acid, syrupy-phosphoric acid).
Yet it is often desirable to employ more of the condensation-agents than is
theoretically required.
For example if one melts together 27 kilogrammes of salicylic acid, and
19 kilogrammes of phenol, with 20 kilogrammes of phosphorpentoxide, that which
becomes contaminated with secondary products forming impure salol, is first
softened in hot water and then washed therein, and then treated with a warm
solution of soda, and it then becomes crystalized.
I. DESCRIPTION OF THE METHOD OF PREPARATION BY MEANS OF
PHOSPIIORPENTOXIDE.
Firstly 100 kilogs. of salicylic-acid are mixed with 55 kilogs. of phosphor-
pentoxide in an enclosed iron boiler provided with a stirrer.
By a gentle heat the operator brings about the reaction in an atmosphere of
carbonic acid gas (in the closed vessel) under gentle pressure.
It is usually
necessary to withdraw the fire as soon as the thermometer shews 65° C. as otherwise
the temperature will rise above 100° C. which, must if possible be avoided.
Preferably the mass is now heated for 3 hours to about 90° C. after the fire has
been withdrawn for half an hour. No further warm development of the reaction
mixture now takes place.
When the temperature increases over 120° C. by the formation of the reaction
products, instead of receiving the desired salicylic-phosphor-acid crystals, a deep
red coloured greasy mass is obtained, which does not possess the capacity for
passing over with phenol into salol.
After three hours gentle heating, the corresponding alcohol is added, namely
the entirely anhydrous melted carbolic acid (phenol) or napthol, in an equivalent
quantity, (of phenol C,H,OH 70 kgr.). The temperature now rises by itself
about 15° to 20° C., and the mass is now stirred without further application of
heat for one hour, when the stop cock which has been closed during the operation,
is opened when the carbonic acid gas pressure has been again restored, and the
bulk is ladled out or drawn off. The whole is then allowed to cool in earthenware
vessels and by standing still it separates into two parts, one below of a deep red
colour containing pyrophosphoric-acid, and above a pale colored paste which is
crystalized and contains salol. This upper layer is then removed and washed with
a hot solution of soda.
If phosphorpentoxide alone is employed in consequence of the refractoriness
of the pyrophosphoric-acid syrups, the liquid salol separates badly. By the
addition of 12 kilogs. of syrupy phosphoric acid of the specific gravity of 1.7 to
100 kilogs. of salicylic acid, after preparing the boilers with a dressing of phenol,
a good separation of the phosphoric-acid from the salol paste is obtainable. The
amount of salol obtainable depends alone on the duration of the action of the
phosphorpentoxide upon the salicylic acids and is proportioned by it. Hence,
from the heightened temperature which results from the action of the phosphor-
pentoxide upon the salicylic acid, it follows that the salicylic acid as such, does
not fall into reaction with the later added phenol, but takes the form of a derived
product which results from the action of the phosphorpentoxide. This new
substance is a warm thick-flowing syrup in a crude condition, which when cold

page_text: with water neutralised with soda and treated with dinatrium-orthophosphate. At
the same time small quantities of salol are obtained, together with salicylic acid
which is deposited from the last lyes of the phosphoric alkalies with muriatic acid.
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 :-
An improved process for obtaining salol or salicylic-acid-ester of phenol and
napthol from salicylic acid by treating
(a) Phosphorpentoxide,
(6) Meta-phosphoric acid,
(c) Syruppy-phosphoric acid,
with a mixture of salicylic acid and phenols or napthols; or a mixture of salicylic
acid mixed and heated with phosphor pentoxide and syruppy phosphoric acid and
the subsequent addition of phenols or napthols; or of a mixture of salicylates
with the alcohol mentioned or with the reaction mixture which is obtained by the
manufacture of salicylic acid, as herein explained and set forth.
Dated this 6th day of September 1893.
S. S. BROMHEAD;
97, Newgate Street, E.C., Agent for Applicant.