Catalytic epoxidation of olefins using MoO3 and TBHP: Mechanistic considerations and the effect of amine additives on the reaction

Efforts were made at developing a simple catalytic epoxidation system for olefins using MoO3 and TBHP as terminal oxidant. Conversions of up to 92% and epoxide selectivities of up to ≥99% were obtained. The epoxidation reaction was accelerated by the addition of catalytic quantities of pyridine and pyrazole. The highest conversion was obtained with styrene (92%) and the highest selectivity with β-methylstyrene (≥99%). For the epoxidation of cyclohexene a number of decomposition products were obtained including a large proportion of 1-(tert-butylperoxy)-2-cyclohexene. Preliminary investigations appear to indicate the presence of peroxo Mo(VI) complexes in the epoxidation reaction mixture.

Graphical abstractA new procedure for the catalytic epoxidation of olefins using MoO3 as catalyst and TBHP as terminal oxidant is reported. The presence of catalytic quantities of pyridine and pyrazole accelerated the reaction.Figure optionsDownload full-size imageDownload as PowerPoint slide