M. N. Slyadnev**, V. A. Kazakov**, E. D. Makarov*,
A. A. Ganeev**, L. N. Moskvin*
*St.Petersburg State University, Dept. of Chemistry
**Lumex Ltd., St. Petersburg; St.Petersburg State
University, Dept. of Chemistry
This paper deals with a liquid extraction system of two immiscible
liquids, i.e. heptane-dichloromethane-acetonitrile and water-acetonitrile
that after confluence form a three-phase system. Each of three chemically
induced phases mainly consists of heptane (1st phase), acetonitrile/ dichloromethane
(2nd phase) and water (3rd phase). Stable interfaces between all of three
phases were observed under flow conditions, when two initial phases were
injected into a microchannel of 200(W)*100(D) μm. The mass transfer of the
model compound (rhodamine 6G) between phases was studied in static conditions
and analytical characteristics of the processes were obtained for different
compositions of initial phases. For microchannel flow conditions, it was
found that equilibrium was almost reached in a 1 second after the confluence
of initial phases. This short time constant was attributed to the fast diffusion
across the chemically induced phases in the microchannel, large area
to volume ratio of the interfacial regions, and to the phase formation mechanism,
which is characterized by the transfer of a large extent of acetonitrile
from the initial phase to a chemically induced phase with simultaneous transfer
of dye molecules.