Oxidation of alkylaromatic compounds with hydrogen peroxide catalyzed by mixed addenda Keggin heteropolyanions

Abstract

Keggin type mixed addenda heteropolyanions containing vanadium atoms such as PV 2Mo 10O 5− 40 are shown to be effective catalysts for the oxidation of alkylaromatic compounds to the respective acetates or alcohols and aldehydes or ketones using 30% hydrogen peroxide as oxidant. Use of spectroscopic techniques including UV-Vis, IR, vanadium-51 and phosphorus-31 NMR, and ESR shows that the H 5PV 2Mo 10O 40 compound is not degraded during the catalytic cycle. Oxidation proceeds by homolytic cleavage of H 5PV 2Mo 10O 40-peroxo intermediates. The resulting hydroperoxy and hydroxy radicals initiate the formation of benzyl radicals which lead to the product formation.