A Na2WO4/H2WO4-based highly efficient biphasic catalyst towards alkene epoxidation, using dihydrogen peroxide as oxidant

Abstract

The tungsten-containing biphasic catalytic system [Na2WO 4/H2WO4/PTR/chloroacetic acid] effectively epoxidizes alkenes with 50% H2O2 as terminal oxidant, under organic solvent-free conditions. The catalytic process is proposed to proceed via a dinuclear tungsten peroxo species with coordinated chloroacetic acid, as suggested by ESI-MS measurements. The catalytic system is suggested to involve tungsten-peroxo and/or peracetic acid type of epoxidation catalyzed by the tungsten(VI) in the presence of an organic acid and H2O 2. The reaction conditions employed for various alkenes for epoxidation are mild compared to the earlier studies and result in high product selectivity and conversion rate. © 2005 Wiley-VCH Verlag GmbH & Co. KGaA.