Environmentally friendly and highly efficient alkenes epoxidation system consisting of [π-C5H5N(CH2)11CH3]3PW4O32/H2O2/ethyl acetate/olefin

The epoxidation of alkenes was successfully catalyzed by a recyclable and environmentally benign catalytic system: [pi-C5H5N(CH2)(11)CH3](3)[PW4O32]/H2O2/ethyl acetate/olefin. This new catalytic system not only capable of catalyzing homogeneous epoxidation of alkenes with unique reaction-controlled phase transfer characters, but also avoids the use of chlorinated solvents. The reactions were conducted in a biphasic mixture of aqueous H2O2/ethyl acetate, and many kinds of alkenes can be efficiently converted to the corresponding epoxides in high yields. The catalyst could be easily recovered and reused after reaction without loss activity. The fresh catalyst, used one and catalytically active species were characterized by P-31 NMR. (C) 2008 Elsevier B.V. All rights reserved.