Process for the Manufacture of New Soaps Containing Sulphur in Chemical Combination.
Year: 1893

page_text: Date of Application, 31st May, 1893-Accepted, 1st July, 1893
COMPLETE SPECIFICATION.
Process for the Manufacture of New Soaps Containing Sulphur in
Chemical Combination.
I, JASPER WETTER, Patent Agent, of 433 Strand, in the County of London,
do hereby declare the nature of this invention and in what manner the same is
to be performed, a communication from abroad by the firm of J. D. Riedel,
Manufacturing Chemists, of Gerichtstrasse, Berlin, in the German Empire, to be
particularly described and ascertained in and by the following statement:-
In the so-called sulphur soaps of commerce the sulphur is only mechanically
mixed with the soap stock; consequently if the latter dissolves, the sulphur
remains behind undissolved and can produce only a slight therapeutic effect on the
skin.
My correspondents, however, have found a process for the manufacture of
sulphur soaps which contain the sulphur in chemical combination and in a form,
which allows the sulphur to act vigorously on the skin. This process is based on
the observation, that all those fatty acids, resinous acids and esters of these acids,
which belong to unsaturated hydrocarbon series, for instance, oleic acid and linoleic
acid, or fats, such as linseed cil and castor oil, on being heated with sulphur at a
temperature ranging between 120 and 160° C., enter into chemical combination
with the same.
The transition of the mere physical solution of sulphur which is at first produced,
to a chemical combination may be recognised by the fact, that a drop of the mass,
on cooling, no longer becomes turbid and milky owing to separation of sulphur, but
remains clear and can be dissolved in oil of turpentine, alcohol and similar solvents
without the elimination of sulphur.
During this absorption of sulphur at a low temperature, the sulphur enters into
chemical combination by simple addition, as may be concluded from the fact, that
no sulphuretted hydrogen, or only a very small quantity of it, is evolved during
the reaction.
The said sulphuretted compounds, obtained as described at a low temperature,
may under suitable conditions be transformed into sulphur soaps, while the sulphur
which has entered the fatty bodies remains in its original chemical combination.
This saponification of the fatty compounds sulphuretted by the addition of sulphur
may be effected in various ways, but must always be carried out at a low
temperature, because a higher temperature would cause partial decomposition, with
elimination of sulphur.
To saponify the fatty acids sulphuretted by chemical addition, the latter are
ground together with the calculated quantity of dilute alkali solution (1 molecule
of alkali to 1 molecule of fatty acid), while the temperature is maintained at
about 25° C. by cooling. The soap thus formed is then relieved of the lye by
pressure.
Or the sulphuretted fatty acids are saponified by dissolving them in two parts of
alcohol (of 90% strength), then adding strong alkali solution until neutralisation,
and finally evaporating to dryness over a water bath at about 50° C.
The fats sulphuretted by addition are saponified by utilizing the property of
cocoanut oil, to transmit its easy saponifiability upon other fats. The sulphuretted
fats are melted at a moderate heat with a quantity of cocoanut oil, depending on
the amount of sulphur which the finished soap is required to contain, subsequently
the calculated quantity of strong alkali lye is stirred into the mixture, the latter is
placed in suitable moulds and allowed to stand, whereby complete saponification is
produced without any considerable rise of temperature.

page_text: The new sulphur soaps obtained by the above process are called "thiosapoles."
They are applicable per se, and also in mixture with other soaps, both as toilet
soaps and as cosmetic and dermatological preparations.
EXAMPLES.
1. For producing sodium-thiosa pole containing about 10% of sulphur in the
shape of an additive compound, I heat 1 kilogramme of oleic acid with 120 grammes
of sulphur for about 4 hours to a temperature ranging between 120 and 160° C.,
whereby the sulphur is dissolved. From the thio-oleic acid thus obtained, the
sodium salt is then produced, either by intimately stirring the same with 600 grammes
of 25 per cent. soda solution, while cooling, and subsequently relieving the pasty
mass from the lye by pressure, or by dissolving the thio-oleic acid in 2 kilogrammes
of 90 per cent. alcohol, adding 430 grammes of 35 per cent. soda solution to produce
saponification, and drying the filtrate over a water bath at about 50° C.
per cent. of
2. For producing a thiosapole cocoanut soap containing about
sulphur in the shape of an additive compound, I treat 1 kilogramme of linseed oil
with 166 grammes of sulphur in the manner described in Example 1, subsequently
I melt together 1 kilo. of the thiolinoelic acid thus produced, with 1 kilo. of cocoanut
When the mass has cooled down to about 25° C., I stir 1 kilo. of 35 per cent.
soda solution into the same, and allow the mixture to stand in suitable moulds until
the saponification is complete.
oil.
In the above examples, the oleic acid and linoelic acid may, of course, be
replaced by other unsaturated acids and fats, such as castor oil, rapeseed oil, the
resinous acids of colophony etc., also instead of soda lye, other bases may be used
for saponification, and to the mixed soaps produced by means of cocoanut oil may
be added also (besides cocoanut oil) other raw materials used in the manufacture of
soap.
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 process for the manufacture of soaps containing chemically combined sulphur,
which consists in heating fatty acids or resinous acids or fatty acid esters (natural
fats and oils) belonging to unsaturated hydrocarbon series, with sulphur to a
temperature ranging between 120 and 160° C., which operation is attended with
chemical addition of sulphur, and subsequently saponifying with bases the thio-acids
and thio-fats thus produced, either alone or with the addition of unsulphuretted fats
or fatty or resinous acids, while avoiding high temperatures, substantially as
described.
Dated this 31st day of May 1893
FAIRFAX & WETTER,
433, Strand, London, Agents.