Kinetics and mechanism of the epoxidation of styrene and substituted styrenes with O2 catalysed by [RuIII(EDTA)(H2O)]-

Abstract Epoxidation of styrene, 2-methylstyrene, 3-chlorostyrene and 4-methoxystyrene with molecular oxygen catalysed by [Ru III (EDTA)(H 2 O)] − ( 1a ) (EDTA = ethylenediaminete-traacetate) was studied as a function of catalyst ( 1a ), substrate and dissolved oxygen concentration in 50% water-dioxane medium. The rate of epoxidation was found to be first order with respect to complex 1a and substrate concentrations and one-half order with respect to dissolved oxygen concentration. At high substrate concentrations a zero-order dependence of rate with respect to substrate concentration was observed in each case. Stoichiometric oxidation of styrene and substituted styrenes by [Ru V = O(EDTA)] − ( 2 ) was studied, and results are compared with the catalytic epoxidation reactions with molecular oxygen.