Liquid poly(ethylene glycol) and supercritical carbon dioxide: a benign biphasic solvent system for use and recycling of homogeneous catalysts.
Poly(ethylene glycol) (PEG), having a molecular weight of 900 or 1500, is a solid at room temperature but a nonvolatile liquid at 40 degrees C under CO2 pressure. Homogeneously catalyzed hydrogenation can be performed in the molten PEG, followed by extraction of the product by supercritical CO2. The catalyst-containing PEG phase which remains in the vessel can be reused for hydrogenation without addition of further catalyst or PEG.
Department of Chemistry, University of California, Davis, California 95616, USA.
David J
DJ
Heldebrant
Philip G
PG
Jessop