ISSN 1070-4272, Russian Journal of Applied Chemistry, 2007, Vol. 80, No. 7, pp. 1097!1100. + Pleiades Publishing, Ltd., 2007.
Original Russian Text + E.V. Ivanov, M.A. Artemova, A.A. Maslov, 2007, published in Zhurnal Prikladnoi Khimii, 2007, Vol. 80, No. 7, pp. 1127!1130.
PROCESSES AND EQUIPMENT
OF CHEMICAL INDUSTRY
Extraction from Raw Materials with a Two-Phase System
of Extractants in an Apparatus for Oscillating Vacuum Boiling
E. V. Ivanov, M. A. Artemova, and A. A. Maslov
St. Petersburg State Academy of Pharmaceutical Chemistry, St. Petersburg, Russia
Received January 23, 2007
Abstract-Extraction of hydrophilic and lipophilic compounds from vegetable raw materials with a two-phase
system of extractants in an apparatus for oscillating vacuum boiling was studied. Dependences of the yield
of target components on the time and hydrodynamic mode of the process were obtained.
If a raw material contains several groups of com-
pounds with widely different solubilities, extraction
is, as a rule, performed in several stages, with differ-
ent solvents used in each stage. Recently, a new
method has found use for extraction of hydrophilic
and lipophilic compounds from vegetable raw materi-
als with a two-phase system of extractants .
Hydrophilic compounds well dissolve in one of these,
e.g., in an aqueous solution of ethanol, and lipophilic
compounds, in the other, e.g., in vegetable oil. It has
been shown that both hydrophilic and lipophilic com-
pounds are extracted from raw materials mostly by
the alcoholic-aqueous phase, from which lipophilic
compounds subsequently pass into the oil phase [2, 4].
Thus, two main consecutive-paallel processes occur
simultaneously: extraction of target components from
vegetable raw materials with the alcoholic3aqueous
phase and extraction of lipophilic compounds from
the alcoholic3aqueous phase into the oil phase. The
third process, extraction of lipophilic compounds from
raw materials with oil, is insignificant.
Despite the strong interest in the given extraction
technique, the effect of hydrodynamic mode in ap-
paratus on the process intensity has been insufficiently
studied, and, therefore, studies in this area are topical.
The aim of this study was to examine the extrac-
tion of hydrophilic and lipophilic compounds from
vegetable raw materials with a two-phase system of
extractants in an apparatus for oscillating vacuum
boiling of the extractant.
The boiling-up of an extractant in an apparatus
for oscillating vacuum boiling occurs as a result of
periodic changes in the volume of a thermostated sys-
tem constituted by a suspension being processed and
a vapor . As the volume of the system increases,
the pressure in it decreases, the alcoholic3aqueous
phase becomes superheated and boils up, with vapor
bubbles forming and growing. As the volume of the
system decreases, the pressure in it grows, vapor
bubbles collapse, boiling terminates, and the heat of
evaporation (condensation) is returned into the sys-
tem. Vapor bubbles are formed throughout the volume
of the alcoholic3aqueous phase. Their number and
size depend on the frequency of boiling-up of the
extractive agent and on the amplitude of oscillations
in the suspension, which characterizes the variation
amplitude of the volume of the system. As the fre-
quency of boiling-ups of the extractant grows, the
number of vapor bubbles increases and their size de-
creases. As the amplitude of suspension oscillations
grows, the growth rate of vapor bubbles and, con-
sequently, the intensity of their hydrodynamic impact
on the suspension become higher.
The process was carried out at 50 to 90oC. The
boiling-up frequency of the extractant was varied
in the range 137.5 s
, and the amplitude of suspen-
sion oscillations, from 0.005 to 0.035 m.
A finely divided (233 mm) grass of common
John’s wort satisfying the requirements of State Phar-
macopoeia  was used as a raw material. The two-
phase system of extracting agents was composed of
vegetable oil (low-polarity solvent) and a 70% aque-
ous solution of ethanol (polar solvent). The use of
the alcoholic3aqueous mixture of the given concentra-
tion provides the most complete recovery of lipophilic
substances from vegetable raw materials . As
tracers characterizing the rate and extent of the proc-
ess were chosen chlorophyll derivatives (in terms of