Synthesis of dicationic alkyl imidazolium peroxopolyoxotungsten-based phase transfer catalyst and its catalytic activity for olefin epoxidation

Abstract

Peroxopolyoxotungsten-based hybrid catalysts modified by dicationic long-chain alkyl imidazolium cations have been synthesized and characterized. The catalytic activity of the catalysts was measured for the epoxidation of olefins with H 2 O 2 . These catalysts proved to be high catalytic activity phase transfer catalysts. In particular, for the catalyst [D 12 min] 1.5 PW 4 O 24 modified by the dodecyl dicationic imidazolium cation, the conversion of cyclohexene and selectivity for epoxycyclohexane were 97.7% and 96.3%, respectively. After the reaction, the catalyst could be recovered simply by filtration and reused four times. The conversion of cyclohexene and selectivity for epoxycyclohexane were still 72.4% and 97.2%, respectively, after recycling the catalyst four times. In addition, this phase transfer catalyst can be applied to the epoxidation of a wide range of olefins. Peroxopolyoxotungsten-based hybrid catalysts modified by the dicationic long-chain alkyl imidazolium cation were synthesized and used as the phase transfer catalyst for cyclohexene epoxidation reactions.