Improvements in and relating to the Manufacture of Saccharin.
Year: 1899

page_text: Date of Application, 11th May, 1899
Complete Specification Left, 12th Mar., 1900-Accepted, 11th May, 1900
PROVISIONAL SPECIFICATION.
Improvements in and relating to the Manufacture of Saccharin.
A communication from LA SOCIÉTÉ CHIMIQUE DES USINES DU RHÔNE, ancienne-
ment, Gilliard, 1'. Monnet et Cartier, of Lyons, France, Manufacturers.
I, GEORGE BELOE ELLIS, of the Firm of J. C. Mewburn & Ellis, of 55 and 56,
Chancery Lane, in the County of London, Chartered Patent Agents, do hereby
declare the nature of this invention to be as follows:-
This invention has reference to the manufacture of saccharin, and more
particularly to that stage of the manufacture in which the toluene sulpho-
chlorides are produced.
In the manufacture of saccharin, the liquid toluene sulpho-chloride which is
required for the purpose is commonly prepared by introducing toluene into a large
excess of chlorosulphonic acid, which is maintained at a temperature not
exceeding 5° C.
My foreign correspondents have now discovered that if the reaction be carried
out at a higher temperature a much larger yield of sulphochlorides, and particu-
larly of liquid sulphochlorides, is obtained, the best effect being produced when
1 part of toluene is run very slowly and with constant stirring into three to
five parts of chlorosulphonic acid maintained at a temperature of about 10° C.
Dated this 11th day of May 1800.
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London,
Chartered Patent Agents.
A communication from LA SOCIÉTÉ CHIMIQUE DES USINES DU RHÔNE; ancienne-
ment, Gilliard, 1'. Monnet et Cartier, of Lyons, France, Manufacturers.
I, GEORGE BELOE ELLIS, of the Firm of J. C. Mewburn & Ellis, of 55 and 56,
Chancery Lane, in the County of London, Chartered Patent Agents, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed to be particularly described and ascertained in and by the following
statement:-
-
This invention has reference to the manufacture of saccharin, and more
particularly to that stage of the manufacture in which the toluene sulpho-
chlorides are produced.

page_text: In the manufacture of saccharin, the liquid toluene sulpho-chloride which is
required for the purpose is obtained by the action of chlorosulphonic acid on
toluene. This action as originally employed had the effect of producing a
mixture of toluene sulpho chlorides with a considerable proportion of toluene
sulphonic acid.
Subsequently Monnet in 1894 invented a process by which the toluene was
converted substantially into toluene sulpho-chlorides. This was effected by
introducing toluene into a large excess of chloro-sulphonic acid which was
maintained at a temperature not exceeding 5° C. He then found that any
excess of temperature above that limit was accompanied by a diminution of the
yield of sulpho-chlorides.
My foreign correspondents have now discovered that the reaction can be
carried out at a higher temperature so as to obtain a larger yield of sulpho-
chlorides and particularly of the liquid sulpho-chloride which is in use in the
manufacture of saccharin. This novel result is obtained by using in lieu of
the technical chloro-sulphonic acid known in 1894 and which is the reagent
giving the results obtained by Monnet, a pure chlorosulphonic acid which has
been freed from sulphuric acid and sulphuric anhydride. This can be effected
by re-distillation of the technical chloro-sulphonic acid or by other suitable
means known to chemists.
If such chloro-sulphonic acid be used with proper precautions, the results
obtained at a temperature higher than 5° C. are superior to those below 5° C.
in the amount of the liquid sulpho-chloride which is alone of technical value.
The temperature may in such case be allowed to rise to 35° C. but the most
useful results are obtained from 10° C. to 20° C. The reaction should be allowed
to take place as quickly as possible compatible with the proper control of the
temperature and prolonged stirring after the whole of the ingredients have been
mixed should be avoided.
An excellent result for instance is produced when one part of toluene is run
very slowly and with constant stirring into three to five parts of chloro-sulphonic
acid maintained at a temperature of about 10° C.
Having now particularly described and ascertained the nature of the said
invention as communicated to me and in what manner the same is to be per-
formed, I declare that what I claim is:―
The improved manufacture of toluene sulpho-chloride suitable for the prepara-
tion of saccharin by the action of a large excess of chloro-sulphonic acid on
toluene at a temperature exceeding 5° C. such chloro-sulphonic acid being free
from sulphuric acid and sulphuric anhydride substantially as described.
Dated this 12th day of March 1900
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London,
Chartered Patent Agents