SELECTIVITIES IN PURE AND MIXED SUPERCRITICAL FLUID SOLVENTS

Solubilities were measured for binary, ternary, and quaternary systems which consisted of various combinations of solid phases, CO//2, and a cosolvent at 35 degree C and at 100-350 bar. Selectivities, which were determined from the data, were analyzed in terms of dispersion, diple-dipole, and acid-base interactions by using a hard-sphere van der Waals model. The results suggest that small amounts of properly selected cosolvents could improve the economics of supercritical fluid extraction significantly due to an increase in selectivities and/or yields along with a reduction in the pressure.