Perfluoroalkyl-Substituted Arylphosphanes as Ligands for Homogeneous Catalysis in Supercritical Carbon Dioxide

摘要

Carbon dioxide in the supercritical state (scCO_2) is an interesting reaction medium thai has recently been established for application in homogeneous catalysis with transition metal complexes. Compared to conventional organic solvents, scCO_2 provides a nontoxic and ecologically benign alternative. Furthermore. scCO_2 is highly miscible with many gaseous reactunts, thus avoiding rate limitations by diffusion processes, as is often encountered with gas liquid-phase reactions. A possible increase in selectivity and activity through special solvent effects in the supercritical medium has also been discussed. Finally, since the solvent properties of scCO_2 can be tuned by variation of pressure and temperature, selective separation directly from the reaction mixture seems possible.