As can be seen from Fig. 1, at constant temperature FOEE
solubility increases with pressure, whereas the solvent selectivity
decreases. Each curve stops at a pressure value (P*) that gives a
homogeneous phase, which is reached at a solubility value of about
16.7 g/kg, corresponding to the complete solubilization of the oil
in the solvent for the stated S/F. The separation process must be
carried out at a pressure lower than P*. Reducing the pressure from
P*, the solubility decreases while the selectivity increases; thus,
at each temperature, an optimal operating pressure must exist.
Furthermore, a vast region of pressure and temperature exists,
wherein solubility decreases as temperature increases. In the range