Liquid-phase epoxidation of olefins by manganese oxide octahedral molecular sieves

Manganese oxide octahedral molecular sieves with a cryptomelane structure (OMS-2) were used to catalyze the oxidation of cyclic olefins and benzylic double bonds with tertiary-butyl hydroperoxide (TBHP) as the oxidant. OMS-2 showed good catalytic activity with high selectivity under mild conditions (substrate:oxidant molar ratio of 1:1) for the oxidation of different substrates that were studied. Cyclooctene gets oxidized to cyclooctene epoxide selectively in the presence of OMS-2 among the different substrates used for oxidation. The order of reaction with respect to cyclooctene was determined to be pseudo-first order using OMS-2 and excess TBHP. The effects of time, reaction temperature, solvents, and amount of catalyst were investigated. Various reaction conditions and conversion of cyclooctene were maximized at 60 °C using acetonitrile as the solvent.