Homogeneous–Heterogeneous Interaction during Catalytic Oxidation of Benzene to Maleic Anhydride

Abstract

IT is now well established that the products of a nominally heterogeneous catalytic reaction can originate, at least in part, from homogeneous reactions. This is particularly true for oxidation reactions, in which both consecutive and concurrent reactions can lead to decreased selectivity. An interesting system has been reported by McCain and Godin¹, who investigated the oxidation of propylene over a catalyst consisting of oxides of bismuth, phosphorus and molybdenum supported on silica. The results suggested that propylene oxide, which formed during the reaction, originated from a gas phase reaction initiated, in turn, by aldehydes produced catalytically. One reaction could not occur without the other, so the system can properly be described as involving an interaction between homogeneous and heterogeneous processes.