While homogeneous catalysts offer many advantages, including high activity and selectivity, they generally present problems at the separation stage of a process, both in product purification and in catalyst recovery. Biphasic systems can provide one way to deal with these problems. The biphasic catalysis systems using supercritical carbon dioxide (scCO₂) as the continuous phase and another green reaction medium, such as water, ionic liquid, polyethylene glycol, respectively, as the stationary catalyst phase are described herein for the metal-mediated chemical reactions. An important advantage of adopting scCO₂ with those biphasic systems from an engineering point of view was the possibility to combine reaction and separation into only one integrated process, namely the so-called homogeneously reacted while heterogeneously separated process. Recent progress in this field is reviewed in this paper.

Key words: biphasic system, homogeneous catalysis, catalyst recycling, supercritical carbon dioxide