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

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 H2O2. These catalysts proved to be high catalytic activity phase transfer catalysts. In particular, for the catalyst [D12min]1.5PW4O24 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.

Graphical AbstractPeroxopolyoxotungsten-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.Figure optionsDownload full-size imageDownload as PowerPoint slide