Homogeneous catalysis and catalyst recovery using supercritical carbon dioxide and ionic liquids

The combination of scCO(2) with a non-volatile liquid such as ionic liquids, water, or poly(ethylene glycol) creates a biphasic mixture suitable for homogeneous catalysis with facile catalyst/product separation and catalyst recycling. Continuous-flow processes are also possible. Dissolution of the CO2 into the nonvolatile liquid during the reaction can have desirable or undesirable effects on the properties of the liquid phase and the reaction performance. Examples of the use of these biphasic systems are described, with an emphasis on systems involving ionic liquids.