Redox Molecular Sieves: Recylable Catalysts for Liquid Phase Oxidations

Abstract

Redox molecular sieves have been synthesized by isomorphous substitution in the framework of silicalite-1 and ALPO-5. CrAPO-5 and CrS-1 were shown to be effective catalysts for the decomposition of secondary alkyl hydroperoxides to the corresponding ketones. In the decomposition of cyclohexyl hydroperoxide the highest selectivity to cyclohexanone (86%) was observed with CrAPO-5. CrAPO-5 was also shown to be an effective catalyst for the oxidation of secondary alcohols to the corresponding ketones, alkylbenzenes to acetophenones and cyclohexane to cyclohexanone using tert-butyl hydroperoxide (TBHP) or O2, as the terminal oxidant. Evidence is presented in support of the reaction taking place inside the cavity of the molecular sieve.