Propane Oxidation on Mo–V–Sb–Nb Mixed Oxide Catalysts: 2. Influence of Catalyst Activation Methods on the Reaction Mechanism

Abstract

This work aims at demonstrating a relationship between the propane oxidation reaction mechanism and the chemical/physical properties of the Mo–V–Sb–Nb mixed oxide catalyst, calcined (500/600°C) and activated (500°C) under oxidative and inert conditions. Calcination and activation under inert conditions yields a catalyst with complex mixed oxides phases (Sb 4Mo 10O 31, ( M y 5+Mo z 5+Mo 6+ 1− y− z ) 5O 14, etc.) and a partial reduced total oxidation state, which favours the formation of propene as the sole primary product and acrylic acid as a major secondary product. In contrast, catalysts calcined and/or activated in an oxidative atmosphere give more oxidised phases (MoO 3 as a major phase), which results in the preferable formation of acetic acid via a route which bypasses propene as an intermediate.