Process for the Distillation of Substances having a High Boiling Point.
Year: 1893

page_text: Date of Application, 23rd Jan., 1893-Accepted, 20th Jan., 1894
1.f
[Communicated from abroad by the Firm of BENNO JAFFE & DARMSTAEDTER,
of No. 16, Salzufer, Charlottenburg, near Berlin, Germany, Manufacturers.].
Process for the Distillation of Substances having a High Boiling
Point.
I, CHARLES DENTON ABEL, of No. 28 Southampton Buildings, Chancery Lane,
in the County of London, Consulting Engineer and Chartered Patent Agent, 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:-
For distilling substances that are not readily volatilised, superheated steam is
generally employed in various manufactures. This employment is based upon the
assumption that the steam vaporizes the particles of the said substances that come
in contact therewith, envelopes the same, and carries them along with it, and that
by this means the distilling of the substance at a temperature below its boiling
point is effected.
The choice of aqueous steam in preference to other gaseous bodies such as air
for effecting the distillation of certain bodies, such for example of glycerine, was
also determined by the partially erroneous supposition that the body to be distilled,
if brought in contact with air at higher temperatures would be subject to
decomposition.
All volatile substances develope vapours already at a temperature considerably
below their boiling point, but these vapours owing to their low tension do not pass
into the receiver.
Now my correspondents have discovered that if a current of a permanent gas
that has no detrimental effect upon the substance to be distilled, be passed into such
substance when in a heated condition, a considerable volatilisation can be obtained
at a temperature far below its boiling point; and they have also discovered that
among other substances aniline can be readily distilled in this way. The said
process is however intended, according to this invention, to be more particularly
applied to the distillation of glycerine by the aid of a permanent gas, and to the use
of atmospheric air as such gas.
It has been found that glycerine begins to distill already at 120° C., and that at
from 170° to 180° C. the distillation is a very active one. Irrespective of the
economical advantage obtained by this method of distillation, owing to the fact that
the production and superheating of steam is entirely dispensed with, the advantage
is also gained thereby that the distillate is of greater purity, and of a better quality
than when produced by steam.
There is no decomposition of the heated glycerine so long as the heating is kept
below the temperature at which the glycerine would also become decomposed in a
current of steam.
The gas employed for this purpose is preferably atmospheric air, a current of
which at the requisite pressure is produced by any suitable air forcing or propelling
apparatus. The glycerine is heated from the outside. The distillate, which passes
from the retort free from aqueous particles, is collected in suitable refrigerating
recipients, which effect its condensation, and of which one or more of the last
through which it passes contain some water for taking up the last traces of glycerine
from the escaping air which formed the vehicle.
The yield obtained is quite as large as that obtained by means of steam.

page_text: Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what I
claim is :
1. The process of distilling substances of a high boiling point whereby such
substances are heated to a temperature below that of their boiling point while at the
same time a current of a permanent gas of such a nature as to have no injurious action
thereon, is led either through or over the surface of such substance, the resulting
mixture of gas and vapour of the said material being led into a refrigerating
apparatus for effecting the condensation of the said vapours, substantially as
described.
2. Effecting the distillation of glycerine according to the process set forth in the
preceding claim, by heating the glycerine to a temperature of about 120° to 180° C.
and passing a current of atmospheric air either through the same or over the
surface thereof substantially as described.
Dated this 23rd day of January 1892
ABEL & IMRAY,
Agents for the Applicant.