Sustainable Green Epoxidation of Terpenes and other Olefins by Dioxirane Generated from H2O2

Abstract

This study examines the catalytic synergy between a nitrile and a ketone for the formation of dioxirane from hydrogen peroxide (H2O2) for the purpose of epoxidizing a wide variety of terpenes and other olefins. The influence of factors such as the amount of nitrile, ketone, reaction time and the pH of the reaction medium on the conversion rate and epoxide yield were systematically evaluated to determine optimal conditions. Experimental findings reveal that under ambient conditions and at pH values above 11, nearly complete conversion and epoxide yields (~100%) are achieved across diverse terpene and other olefin substrates. The reaction process is simple and efficient, proceeding without any pre-synthesized solid catalyst, whereas readily available acetonitrile and acetone act as co-catalysts and can be recycled indefinitely, facilitating large-scale implementation. The combination of complete substrate conversion and quantitative epoxide yield, together with the use of low-cost raw materials that generate no waste, ambient reaction conditions and the perpetual recyclability of the reagents, renders this process more pertinent than other epoxidation techniques and easier to implement on an industrial scale in response to the current industrial demand for epoxides.