Optimization of cyclohexene epoxidation with dilute hydrogen peroxide and silica-supported titanium catalysts

摘要

The results of activity and selectivity in the epoxidation of cyclohexene with dilute hydrogen peroxide can be improved by careful optimization of the catalyst properties and the reaction conditions. The type of silica support, the silanization with long hydrocarbon chains and mainly the slow addition of hydrogen peroxide are important factors. This slow addition not only noticeably improves the selectivity in terms of epoxidation products but also leads to a better recoverability of the catalyst, showing the role of the radical pathway in deactivation and titanium leaching. In the best case the catalyst can be resulted at least three times with very low titanium leaching, and an overall productivity of 228 mmol epoxidation products per mmol Ti.