Improvements in the Production of Salicylic Acid Derivatives Containing Chlorine and Sulphur.
Year: 1891

page_text: Date of Application, 24th Mar., 1891
Complete Specification Left, 11th Dec., 1891-Accepted, 16th Jan., 1892
PROVISIONAL SPECIFICATION.
Improvements in the Production of Salicylic Acid Derivatives
Containing Chlorine and Sulphur.
I JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of
Middlesex Gentleman do hereby declare the nature of this invention which inven-
tion 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:-
In the Specification of Letters Patent dated October 8th 1888 No. 14,443 a
process is described according to which dithio-salicylic acid is obtained by the
action of one molecular proportion of chloride of sulphur (S,Cl₂) upon two mole-
cular proportions of salicylic acid.
Further investigation of the nature of this reaction has shown that with the
employment of more than one molecular proportion of the sulphur.chloride (S,Cl₂)
upon two molecular proportions of salicylic acid at a temperature of from 100
to 150 degrees Centigrade other products such as higher sulphurised salicylic acids
result.
In order to obtain tetra-thio-di-salicylic acid two molecular proportions of S,Cl,
are treated with two molecular proportions of salicylic acid and a quantity of a
thio-acid is obtained which corresponds to the theoretical amount and which is
regarded as a tetra-thio-disalicylic acid.
On the other hand the analyses of the substance purified with ether indicates an
amount of sulphur equal to 21 per cent. whereas 32 per cent. is theoretically
necessary for the tetra-thio-disalicylic acid. A qualitative examination of the
substance indicates a large proportion of chlorine (10.5 per cent.). The action of
more than one molecular proportion of chloride of sulphur upon two molecular
proportions of salicylic acid causes chlorine and sulphur to simultaneously enter the
product formed. The resulting body contains 21 per cent. of sulphur and 10.5 per
cent. of chlorine. It is not to be regarded as a simple body but as a mixture of
higher sulphurised and less chlorinated and higher chlorinated and less sulphurised
products both of which cannot be completely separated. A simple body is obtained
when not less than 4 molecular proportions of S,Cl, are caused to act upon two
molecular proportions of salicylic acid.
The reaction is represented by the following equation.
that is to say a tetra-thio-dichloro-disalicylic acid as indicated by the analysis is
obtained. The analysis of the pure substance shows that it contains 27.1 per cent.
40 of sulphur and 12.9 per cent. of chlorine whereas the above formula indicates 27.17
The somewhat smaller
and 15 of these substances respectively as being necessary.
proportion of chlorine is attributable to the fact that the action of the chloride of

page_text: sulphur even when an excess is employed is greatly impeded towards the end of
the operation by the tendency of the reacting mass to solidify and that the
substance is not obtained in a crystallised condition whilst some sulphur goes into
solution when the product is dissolved in the ether.
The production of the tetra-thio-di-chloro-disalicylic acid is performed as
follows.
27-6 parts by weight of salicylic acid are intimately mixed with 55 parts by
weight of chloride of sulphur (S,Cl₂) in an enamelled agitating vessel and stirred
whilst the temperature is very slowly raised to 120 degrees Centigrade. Streams
of hydrochloric acid gas are given off and as the evolution of gas diminishes the
temperature is raised to from 135 to 140 degrees Centigrade the heating being
continued until no more hydrochloric acid escapes. The now viscous mass is of a
dark yellow colour and becomes completely solid on cooling. It is dissolved in
water with 10-6 parts by weight of soda and the sulphur formed is filtered off.
. The filtered solution is precipitated whilst in a heated condition with hydrochloric
acid the free acid separating out in the form of resin.
This is now accurately neutralised with soda evaporated and dried. A greenish-
yellow mass is formed, which dissolves readily in water with a brownish-yellow
colour. The free tetra-thio-dichloro-disalicylic acid is insoluble in cold water but
dissolves readily in ether spirit methyl alcohol and the like and is obtained or
extracted from these solvents in the form of a clear yellow mass showing no
tendency to crystallise.
The alkali salt as well as the magnesium salt and lithium salt is readily soluble
in water. The earthy alkali and metallic salts on the other hand form a yellow to
grey coloured precipitate.
Dated the 24th day of March 1891
J. H. JOHNSON & Co.,
Agents.
COMPLETE SPECIFICATION.
Improvements in the Production of Salicylic Acid Derivatives
Containing Chlorine and Sulphur.
I, JAMES YATE JOHNSON, of 47 Lincoln's Inn Fields, in the County of
Middlesex Gentleman, 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 :-
In the Specification of Letters Patent dated October 8th 1888, No. 14,443 a
process is described according to which dithio-salicylic acid is obtained by the
action of one molecular proportion of chloride of sulphur (S,Cl₂) upon two mole-
cular proportions of salicylic acid.
Further investigation of the nature of this reaction has shewn that with the
employment of more than one molecular proportion of the sulphur chloride (SC)
upon two molecular proportions of salicylic acid at a temperature of from 100 to 150
degrees Centigrade other products such as higher sulphurised salicylic acids result.
In order to obtain tetra-thio-disalicylic acid two molecular proportions of S.Cl₂ are
heated with two molecular proportions of salicylic acid and a quantity of a thio
acid is obtained which corresponds to the theoretical amount and which is regarded
as a tetra-thio-disalicylic acid.
On the other hand the analysis of the substance purified with ether indicates an
amount of sulphur equal to 21 per cent. whereas 32 per c.nt. is theoretically
necessary for the tetra thio-disalicylic acid. A qualitative examination of the
substance indicates a large proportion of chlorine (10.5 per cent.). The action of
more than one molecular proportion of chloride of sulphur upon two molecular

page_text: proportions of salicylic acid causes chlorine and sulphur to simultaneously enter
the product formed. The resulting body contains 21 per cent. of sulphur and 10.5 per
cent. of chlorine. It is not to be regarded as a simple body but as a mixture of
higher sulphurised and less chlorinated and highly chlorinated and less sulphurised
5 products both of which cannot be completely separated. A simple body is obtained
when not less than 4 molecular proportions of S,Cl, are caused to act upon two
molecular proportions of salicylic acid.
The reaction is represented by the following equation :—
that is to say a tetra-thio dichloro disalicylic acid as indicated by the analysis is
obtained. The analysis of the pure substance shews that it contains 27-1 per cent.
of sulphur and 12.9 per cent. of chlorine whereas the above formula indicates 27.17
and 15 of these substances respectively as being necessary. The somewhat smaller
proportion of chlorine is attributable to the fact that the action of the chloride of
sulphur even when an excess is employed is greatly impeded towards the end of the
operation by the tendency of the reacting mass to solidify and that the substance
is not obtained in a crystallised condition whilst some sulphur goes into solution
when the product is dissolved in the ether.
The production of the tetra-thio-di-chloro-disalicylic acid is performed as
follows:-
27.6 parts by weight of salicylic acid are intimately mixed with 55 parts by
weight of chloride of sulphur (S,Cl,) in an enamelled agitating vessel and stirred
whilst the temperature is very slowly raised to 120 degrees Centigrade. Streams
of hydrochloric acid gas are given off and as the evolution of gas diminishes the
temperature is raised to from 135 to 150 degrees Centigrade the heating being
continued until no more hydrochloric acid escapes. The now viscous mass is of a
dark yellow colour and becomes completely solid on cooling. It is dissolved in
water with 10-6 parts by weight of soda and the sulphur formed is filtered off.
The filtered solution whilst in a heated condition is precipitated with hydrochloric
acid, the free acid separating out in the form of resin.
This is now accurately neutralised with soda evaporated and dried. A greenish
yellow mass is formed which dissolves readily in water with a brownish yellow
colour. The free tetra-thio-dichloro-disalicylic acid is insoluble in cold water but
dissolves readily in ether, spirit, methyl alcohol and the like and is obtained, or
extracted from the solvents in the form of a clear yellow mass, shewing no tendency
to crystallise.
The alkali salts, the magnesium salt and lithium salt are each readily soluble in
water. The earthy alkaline salts and metallic salts on the other hand, form a
yellow to grey coloured precipitate.
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 :-
The production of derivatives of salicylic acid containing chlorine and sulphur

page_text: simultaneously by heating the salicylic acid with from equal to double (or greater)
molecular proportions of chloride of sulphur (S,C,) to from 100 to 150 degrees
Centigrade.
Dated this 11th day of December 1001
J. H. JOHNSON & Co.,
Agents.