Kinetic Studies and Reaction Network in the Epoxidation of Styrene Catalyzed by the Temperature-Controlled Phase-Transfer Catalyst [(C18H37)2(CH3)2N]7[PW11O39]

The olefin epoxidation reaction is of great interest in recent years since epoxide is considered an important intermediate for a wide application range. H2O2-based catalytic epoxidation possesses the advantages of being cheap, green, and safe, which are quite advantageous in chemical technology. A phase-transfer catalyst, especially the phosphotungstate catalyst, has been applied in the epoxidation reaction with a high reaction rate and moderate reaction conditions. In this work, a phase-transfer catalyst, [(C18H37)2(CH3)2N]7[PW11O39], has been synthesized, and it showed high catalytic efficiency in styrene epoxidation. The influence of reaction time, temperature, oxidant concentration and amount, catalyst amount, and substrate concentration on the reaction performance was studied. A styrene conversion of 90.1% and selectivity of 90.6% could be achieved at 85 °C for 1 h with 3 equiv of H2O2 and 1.5 mol % catalyst. More importantly, kinetic models for the reaction network have been studied to optimize the reaction conditions and limit the side reactions.