Search

CF3CHFCF2OCH2CF3 (1,1,2,3,3,3-hexafluoropropyl--trifluoroethylether), one of the third generation CFC alternatives, was obtained in high yield and selectivity from the hydroalkoxylation reaction of hexafluoropropene with 2,2,2-trifluoroethanol conducted in the presence of a catalytic system consisting of a potassium salt and an ionic liquid, 1-butyl-3-methylimidazolium chloride ([BMIm]Cl). The formation of commonly observed olefinic side products in the hydroalkoxylation catalyzed by potassium salts was greatly reduced by the co-presence of [BMIm]Cl. Theoretical calculations and mechanistic studies suggested that potassium ion is largely responsible for the formation of olefinic side products. [Copyright &y& Elsevier]

Abstract: Phosphine adducts of zinc(II) halides, ZnX2L2 (X=Cl, Br, I; L=PMe2Ph, PEt3, PBu3, PPh3, PCy3), prepared by the reaction of ZnX2 with two equivalents of corresponding phosphines, showed high activities for the coupling reaction of CO2 and ethylene oxide to produce ethylene carbonate. The catalytic activity of ZnX2L2 was hardly affected by the nucleophilicity of the phosphine ligands, with the exception of ZnX2(PCy3)2, but depended strongly on the nature of halide ligands. An active species containing ethoxyphosphonium ligands, Zn3Br6[μ-OCH2CH2-P(C6H5)3]3, was isolated and characterized by X-ray crystallography, elemental analysis, and NMR spectroscopy. The mechanistic pathway for the formation of active species and cyclic carbonates is discussed. [Copyright &y& Elsevier]