Multiphase equilibrium in mixtures of [C(4)mim][PF6] with supercritical carbon dioxide, water, and ethanol: Applications in catalysis

Abstract

The ionic liquid [C(4)mim][PF6] and supercritical carbon dioxide produce multiphase systems when mixed with ethanol and water. Mixtures of these four solvents can be made to go, by small changes in composition, through a succession of phase changes, involving one, two and three-phase situations. Increasing carbon dioxide pressure induces first the appearance of an intermediate liquid phase and later the merging of this phase with the gas, leaving all the ionic liquid in a separate, denser liquid. This succession is suitable to carry out reaction cycles in ionic liquid-based solvents, with complete recovery of the reaction product by CO2 decompression