Progress in the study of biphasic systems prompted by supercritical carbon dioxide and their applications to organic syntheses

Homogeneous catalysts offer many advantages, including high activity and selectivity, while 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 (scCO(2)) 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 scCO(2) 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.