Selective Aerobic Oxidation of Cumene to Acetophenone Via N-Hydroxymaleimide Fabricated by a Sequential Copolymerization and Imidization

Selective oxidation of cumene to value-added acetophenone is of great importance and environmental friendliness. N-hydroxymaleimide (NHMI) was immobilized on a polymer substrate via co-polymerization followed by an imidization in this work, and the catalyst was characterized and tested for oxidation of cumene to acetophenone. The catalyst was found active and selective for the transformation from cumene to acetophenone. The optimized catalyst exhibited a cumene conversion of 93.3 % and a selectivity to acetophenone of 79.2 %. The cumene oxidation catalyzed by the immobilized NHMI copolymers may proceed in the presence of the cocatalyst Co2+ 2+ by a radical way based on the key intermediates or free radicals for the chain propagation of the auto- oxidation reaction observed. Accordingly, a reaction network and mechanism were proposed. The synthesized NHMI catalysts and the fabrication method may shed some light on the development of immobilized catalysts for the activation and selective oxidation of benzylic C-H bonds.