IMPROVEMENTS IN THE MANUFACTURE OF STEARIC ACID
Year: 1872

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane,
in the County of Middlesex, Patent Agent, for the Invention of
"IMPROVEMENTS IN THE MANUFACTURE OF STEARIC ACID."-A communi-
cation from abroad by Edouard Deïss, of Marseilles, France.
Sealed the 25th April 1873, and dated the 8th November 1872.
PROVISIONAL SPECIFICATION left by the said. Alexander Melville
Clark at the Office of the Commissioners of Patents, with his
Petition, on the 8th November 1872.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County
of Middlesex, Patent Agent, do hereby declare the nature of the said.
Invention for "IMPROVEMENTS IN THE MANUFACTURE OF STEARIC ACID," to be
as follows:-
It is well known that in the manufacture of stearic acid by either of
the ordinary methods, whether by saponification, by the aid of lime, or
by acid saponification and distillation fatty acids obtained by either
method are first pressed in a cold state in an ordinary vertical press, and

page_text: .
the cakes of stearic acid obtained by this preliminary pressing are then
placed in a second horizontal press termed a hot press, by the aid of
which the last vestiges of the oleic acid remaining after the first pressing
are expressed. This second hot pressing necessitates the employment of
complicated machinery which is kept in order only at a great expense,
in addition to which there is the further disadvantage of being unable
to obtain "pressings" of uniform quality, as according to the degree of
heat employed the stearic acid will either contain but little oleic acid
and be partially expressed through the woolen bags employed, together
with the oleic acid; or on the other hand the stearic acid will be obtained
highly charged with oleic acid.
According to this Invention the employment of hot pressure is entirely
dispensed with in the preparation of stearic acid, whereby a considerable
saving in the cost of manufacture is effected both as regards the
machinery required and the increased quantities obtainable.
The Invention consists in the employment of sulphuret of carbon or
other solvents volatilizing at low temperatures for separating (by one or
more pressings in a cold state) the oleic acid contained in cakes of
stearic acid.
The following is a description of the Invention:-I take stearic acid 1
mixed with oleic acid in the same condition as when treated by the
ordinary processes, and effect the dissolution of the fatty acids in
sulphuret of carbon, for example, by the aid of suitable apparatus,
taking care to avoid any loss of volatile products.
This operation may
be conducted in an ordinary still, similar to those used in oil refineries.
When the fatty acids are completely dissolved and the matters become
intimately mixed I run the liquid in a pasty condition into moulds,
taking care that the surrounding temperature shall be as cool as possible.
When the moulds are perfectly cool and the cakes (consisting of stearic
acid containing fixed sulphuret of carbon) are sufficiently hard to be easily
removed therefrom I subject them while in a cold state to pressure,
whereby the oleic acid (which is more soluble in sulphuret of carbon
than the stearic acid) is expelled, together with the sulphuret of carbon,
by which it is held in solution from among the crystals of stearic acid,
the formation of said crystals being moreover facilitated by the presence
of the sulphuret of carbon. When sufficiently pressed the resulting
blocks of stearic acid are melted and agitated by the action of steam

page_text: in order to remove any traces of sulphuret of carbon which the stearic
acid might still contain.
By pressing in a cold state as described I am also enabled to utilize
the margarine obtainable from the residues of all kinds of animal and
vegetable oils, for which hot pressing is unsuited, owing to the tempera-
ture required being higher than the melting point of margaric acid, and
which would consequently be expelled through the woolen bags like the
oleic acid.
The Invention is also applicable for the preparation of oleine from
tallow for lubricating machinery, the treatment being exactly similar to
that of the cakes of stearic acid. The proportions of sulphuret of carbon
required will necessarily vary with the proportion of stearic acid which
the cakes of fatty acid may contain, but in ordinary cases the sulphuret
of carbon is used in the proportion of about 20 per cent. of the fatty acid,
resulting from the first cold pressing.
As low temperatures are very favorable in the manufacture of stearic
acid according to this improved method I reserve the right of using any
means of cooling in the treatment of the cakes of fatty acid with
sulphuret of carbon, and also while pressing the same.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alexander Melville Clark in the Great Seal Patent
Office on the 7th May 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighth day of November, in the year
of our Lord One thousand eight hundred and seventy-two, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Alexander Melville Clark, Her special
licence that I, the said Alexander Melville Clark, my executors, adminis-
trators, and assigns, or such others as I, the said Alexander Melville
Clark, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times thereafter

page_text: during the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "IM-
PROVEMENTS IN THE MANUFACTURE OF STEARIC ACID," a communication to me
from abroad by Edouard Deïss, of Marseilles, France, upon the condition
(amongst others) that I, the said Alexander Melville Clark, my executors
or administrators, by an instrument in writing under my, or their, or one
of their hands and seals, should particularly describe and ascertain the
nature of the said Invention, and in what manner the same was to be
performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date
of the said Letters Patent.
NOW KNOW YE, that I, the said Alexander Melville Clark, do hereby
declare the nature of the said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and
by the following statement, that is to say :-
It is well known that in the manufacture of stearic acid and candles
by either of the ordinary methods of calcareous saponification or of acid
saponification and distillation the fatty acids obtained are first pressed in
a cold state in an ordinary vertical press, and the cakes of stearic acid
obtained by this preliminary pressing are then placed in a second hori-
zontal press termed a hot press, by the aid of which the last vestiges of
the oelic acid remaining after the first pressing are expressed in a more
or less perfect manner. This second hot pressing necessitates the
employment of complicated machinery, which is kept in order only at a
great expense, in addition to which there is the further disadvantage of
being unable to obtain "pressings" of uniform quality, as according to
the degree of heat employed the stearic acid will either contain but little
oleic acid. and will be partially expressed through the woollen bags
employed; or on the other hand the stearic acid obtained will still
contain a large proportion of oleic acid. According to this Invention
the employment of hot pressure is entirely dispensed with in the pre-
paration of stearic acid, whereby a considerable saving in the cost of
manufacture is effected as regards the machinery required, and increased
products are obtainable.
The Invention consists in the employment of sulphuret of carbon or
other solvent volatilizing at low temperatures for separating (by one or

page_text: more pressings in a cold state) the oleic acid contained in cakes of stearic
acid.
The following is a description of the Invention:-I take stearic acid
containing oelic acid in the same condition as when ready to be treated
by the ordinary processes, and I effect the dissolution of the fatty acids
in sulphuret of carbon, for example, by the aid of suitable apparatus,
taking care to avoid any loss of volatile products. This operation may
be conducted in an ordinary still, similar to those used in oil refineries,
When the fatty acids are completely dissolved and the matters become
intimately mixed I run the liquid in a semi-pasty condition into moulds,
taking care that the surrounding temperature shall be as cool as possible.
When the moulds are perfectly cool, and the cakes (consisting of stearic
acid containing fixed sulphuret of carbon) are sufficiently hard to be
casily removed therefrom, I subject them while in a cold state to pressure
in a hydraulic press, whereby the oelic acid (which is more soluble in
sulphuret of carbon than the stearic acid) is expelled, together with the
sulphuret of carbon by which it is held in solution, from among the
crystals of stearic acid, the formation of said crystals being moreover
facilitated by the presence of the sulphuret of carbon. When sufficiently
pressed the resulting blocks of stearic acid are melted and agitated by
the action of steam in order to remove any traces of sulphuret of carbon
which the stearic acid might still contain.
By pressing in a cold state as described I am also enabled to utilize
the margarine obtainable from the residues of all kinds of animal and
vegetable oils, for which hot pressing is unsuited, owing to the tempera-
ture required being higher than the melting point of margaric acid, and
which would consequently be expelled through the woollen bags like
the oleic acid.
The Invention is also applicable for the preparation of oleine from
tallow for lubricating machinery, the treatment of the tallow being
exactly similar to that of the cakes of stearic acid. The proportion of
sulphuret of carbon required will necessarily vary with the proportion of
stearic acid which the cakes of fatty acid may contain, but in ordinary
cases the sulphuret of carbon is used in the proportion of about 20 per
cent. of the fatty acid resulting from the first cold pressing.
As low temperatures are very favorable in the manufacture of stearic
acid, according to this improved method, I reserve the right of using any

page_text: means of refrigeration in the treatment of the cakes of fatty acid with
sulphuret of carbon, and also while pressing the same.
Having described the nature of the Invention and the manner in
which the same is to be performed, I declare that what I claim as the
Invention to be protected by the herein-before in part recited Letters
Patent is,
-
1st. The application of liquid solvents volatilizing at low temperatures
for separating (by one or more cold pressings) the oleic acid contained
in cakes of stearic acid, whereby an increased product is obtained and
the slow process and costly machinery required in hot pressing are
rendered unnecessary, while it also permits of the obtention of the
margarine from residues of all kinds of vegetable and animal oils for
which hot pressing is unsuited, all as herein-before described.
2ndly. The application of the same treatment in the preparation of
oleine from tallow for lubricating machinery, as herein-before described.
In witness whercof, I, the said Alexander Melville Clark, have
hereunto set my hand and seal, this Seventh day of May, in
the year of our Lord One thousand eight hundred and seventy-
three.