An improved method is demonstrated for the efficient and selective epoxidation of alkenes in the absence of water using 0.5 mol% methyltrioxorhenium (VII) (MTO) catalyst, urea-hydrogen peroxide (UHP) as the stoichiometric oxidant and a catalytic quantity of the heterocyclic aromatic amine base, pyrazole. This method gave conversions comparable to those using 0.5 mol% MTO, 30% aqueous H2O2 and pyridine (12 mol%) for a number of simple olefin substrates. A kinetic study was undertaken using trans-beta-methylstyrene as substrate to compare the rate of this MTO catalytic epoxidation reaction with the MTO/H2O2 catalytic epoxidation under other conditions. It was found that the reaction rate profile observed for this epoxidation under our conditions mirrored that for the epoxidation reaction which used 0.5 mol% MTO, 30% aqueous H2O2 and pyridine (12 mol%). (C) 2004 Elsevier B.V. All rights reserved.