Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 1, pp. 38−41.
Pleiades Publishing, Ltd., 2009.
Original Russian Text
I.G. Chudotvortsev, O.B. Yatsenko, 2009, published in Zhurnal Prikladnoi Khimii, 2009, Vol. 82, No. 1, pp. 40−43.
OF SYSTEMS AND PROCESSES
Distribution of Components in Aqueous Systems
of Nonelectrolytes at Oriented Ice Crystallization
I. G. Chudotvortsev and O. B. Yatsenko
Voronezh State University, Voronezh, Russia
Received November 27, 2007
Abstract—Data are presented on the kinetics and distribution of components at the nonequilibrium crystallization
of ice in aqueous system of a nonelectrolyte (water–saccharose) in an original installation operating on the
semiconductor thermoelements. The obtained information is important for the better understanding of the nature
of aqueous solutions of nonelectrolytes at the temperature T ~ 0°C and form the practical viewpoint as well for
the solving a problem of separation of components in aqueous systems.
The processes of oriented crystallization can be used
for both exploring the aqueous systems of nonelectrolytes
at low temperature and for the creation of the methods
of separation and puriﬁ cation. In this work the oriented
crystallization was carried out using special original
installation operating on the basis of the Peltier effect.
Cooling of solution in this case is performed by means
of a cooling pipe immersed into the bulk solution. The
cooling rate iss controlled by changing the current
magnitude in the thermoelement that defines the
temperature difference between their hot and cold joints
and the respective heat ﬂ ow through the cooling pipe.
Earlier  with this procedure has been investigated
the processes of crystallization in pure water and in
sodium chloride solutions. For the elucidation of general
regularities of the process it is necessary to study also
the solutions of nonelectrolytes because behavior of the
latter at low temperature was not sufﬁ ciently studied,
in particular near the points of phase transitions.
Therefore we used as the object of investigation a typical
nonelectrolyte saccharose that is useful owing to its high
solubility in water and the possibility of carrying out the
study in a wide range of concentration.
The system saccharose–water has been studied
earlier by the method of fractional melting . The
information obtained concern position of eutectic point
in this system. But at the study several problems appeared
due to anomalous behavior of the system in the vicinity
of the presumed eutectic point. Therefore seems actual
further study of this system by the method of oriented
Elimination of heat from the bulk solvent is
advantageous in several aspects over the cooling of
solution at its surface from the viewpoint of the efﬁ ciency
of components separation. The dissolved substance is
stepwise replaced by the crystallization front from the
bulk center rather than from surface, and capture of the
substance by the forming ice is much diminished. The
heat elimination is performed via the cooling pipe that,
depending on a certain task, can be immersed into the
solution at a given point. Direction and value of the heat
ﬂ ow can be deﬁ ned by the modules direction an electric
current magnitude in them. The installation is depicted
in Fig. 1.
Between the cold joints of the modules (1) connected
consecutively into electric chain is mounted the cooling
pipe (2) made of aluminum. For heat elimination from
the hot joints is used a heat exchanger (3) to which
the cooling liquid (water) is passed from the hose
(4). The thermoelectric modules take heat away from
the cooling pipe immersed to the solution (5). At the
cooling, on the cooling pipe occurs crystallization of
ice (6). The saccharose solution 150 ml volume varied
by concentration was placed into plastic vessel
and 50.0 ml of the solution was crystallized using the