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 degreesC using acetonitrile as the solvent. (C) 2004 Elsevier Inc. All rights reserved.