A New or Improved Process for Separating Solid or Fluid Substances Dissolved in Alcohol, Ether, or Chloroform without Evaporation of the Solvent.
Year: 1892

page_text: Date of Application, 19th Dec., 1892-Accepted, 4th Feb., 1893
COMPLEIE DREIFICATION.
A New or Improved Process for Separating Solid or Fluid Substances
Dissolved in Alcohol, Ether, or Chloroform without Evaporation
of the Solvent.
I, CARL WEITENKAMPF, Gentleman, of 15 Flieder Strasse, 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 :-
This invention relates to a new or improved process of separating solid or fluid
substances dissolved in alcohol ether or chloroform without evaporating the solvent.
The process consists of the solution being cooled considerably saturated with
carbonic acid under pressure and being made to pass through filtering material.
It is necessary for the success of the process that variation of pressure be
avoided that is to say that the saturation and filtration of the cooled solution
saturated with carbonic acid be carried out under uniform conditions of pressure.
It is also necessary that there be no alteration in the temperature of the solution
in its various stages of treatment that is to say that the temperature at which the
solid or fluid substances dissolved in the solvent are separated be as far as possible
the same during the entire time of the treatment including the filtering.
The filtering material is the means for absorbing the substances separated from
the solvent.
The filtering material partly serves for the absorption of small quantities of
polluting substances and in such case it is best made of prepared charcoal and it
partly serves for separating solid precipitates from the solvent.
In that case the filtering material is best made of cellulose.
The filtration will be modified on these points exactly according to the nature of
the separations to be effected by the process.
Sometimes the object of the filtering material is the absorption of minute polluting
substances at other times it is the separation of firm precipitates from the solvent
when the main point is to obtain the said precipitates.
The solvent which has passed the filtering material is absolutely free from the
solid or fluid substances which were in the solution the carbonic acid (still in
solution) used for saturating purposes can by suction be removed therefrom
and can again be condensed and thus be used for the purpose of saturating fresh
solutions.
According to the above described process the purification of alcohol (for instance)
can be effected by removing the fusel oils found therein-or solutions obtained by
extraction by means of alcohol and ether chloroform etc. can be worked for the
purpose of recovering or winning the extractive substances which can be obtained
by the above mentioned process without evaporating the solvent.
The cooling of the solutions to be treated for the purpose of purifying same or
obtaining their extractive substances is effected by any suitable cooling means as
for instance fluid carbonic acid which absorbs as is well known a great deal of
warmth or by the evaporation of ether etc.
By packing the holder (for the solution to be treated) in a suitable cooling
mixture and by isolating the same by layers of silicious quartz sawdust etc. the
influence of the warmth of the outside air etc. is excluded so that the treatment of
the solution is carried out at as far as possible a constant (low) temperature.
The solution to be treated is cooled to such a temperature as that at which the
dissolved substances (or substances to be removed or extracted) can be separated
from the solution with the aid of carbonic acid and then carbonic acid at a suitable
pressure is let into the solution in order to saturate the solution therewith and the
whole is passed through a suitable filter or filtering devices.

page_text: The latter is suitably formed of filters placed over each other the individual
filtering vessels of which are to be carefuly cooled in any suitable way (such as
herein before described for cooling the holder which receives the solution) the filters
being so arranged that the solution successively passes through finer and closer
filtering material which is held in position by sieve floors.
From the filter which retains the last portions of the substances to be separated
or extracted from the original solution the fluid which is now quite pure that is the
solution fluid (as for instance alcohol ether chloroform) freed from the polluting or
extracted substances reaches a holder without there having been any evaporation
thereof and the purified fluid can be drawn from such bolder.
The pressure required for carrying out the process is best obtained by fluid carbonic
acid at a high pressure which serves at the same time the purpose of saturating the
solution.
The holders containing the filtering materials and connections are tightly closed
throughout and are connected with each other in such a way that the carbonic acid
from the holder can be turned off for further use from the pipe leading to the holder
and diverted so as to give direct pressure in the filters and the carbonic acid obtained
from the purified solution can be again forced into said holder and thus used over
and over again.
The fluid obtained still having a low temperature can for the purpose of using
its cold before being stored be used in a set of pipes for cooling the solution pre-
paratory to its treatment.
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:
-
The herein described process for separating solid or liquid substances dissolved
in alcohol ether or chloroform without evaporating the solvent and in which the
solution is first cooled to a temperature of about 20° to 25° C. is then saturated
under pressure with carbonic acid and is lastly made to pass through filtering
materials the same conditions of pressure and temperature being maintained
throughout by the means and in the manner and for the purposes substantially as
hereinbefore set forth.
Dated this 19th day of December 1892.
TONGUE & BIRKBECK,
34, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.