Epoxidation of alkenes using inorganic polymer of silica zirconia molybdate as catalyst

• A new heterogeneous molybdenum catalyst was synthesized for oxidation of olefins.
• High activity and selectivity were obtained for the formation of the epoxides.
• The catalytic activity is influenced by the amount of adsorbed Mo on the polymer.
• Adsorption of the Mo is related to ratio of Zr/Si and S/Zr.
• Amount of adsorbed Mo plays a crucial role in the particle size and morphology.

Silica zirconia sulfate was prepared by sol–gel copolymerization of the sulfated zirconium octanoxide and tetraethylorthosilicate (TEOS). Active polymer oxidation catalysts were obtained by introducing sodium molybdate into the polymer by a ligand exchange reaction. The prepared inorganic polymer designated as SZ-Mo was characterized by FT-IR, SEM, XRD, N2 sorption isotherms, and ICP techniques. It was found that SZ-Mo successfully catalyzes the epoxidation of cyclooctene, cyclohexene, trans-stilbene, and norbornene with 22–95% conversion and 60–100% selectivity. The dependence of the SZ-Mo catalytic activity to the amount of adsorbed Mo within the polymer as well as the study of catalyst stability during the course of reactions will be described in this presentation.

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