Propane oxidation on Mo-V-Sb-Nb mixed-oxide catalysts 1. Kinetic and mechanistic studies

摘要

Kinetic and mechanistic investigation were made of propane oxidation to arylic acid over Mo_1V_(0.3)Sb_(0.25)Nb_(0.08)O_n catalyst, calcined at 600 deg C in air, and activated at 500 deg C in O_2/H3. The kinetic study allowed determination of the orders of propane disappearance and major products formation, and also emphasisted the crucial effect of water on the activation energies of propane and oxygen. Propane and independently propene oxidation of various contact times enabled us to differentiate primary from secondary products and to propose a reaction scheme with three pathways: two major pathways leading to acrylic and acetic acids and a minor pathway leading to propionic acid. It was shown that acetic acid is formed via a route bypassing propene as an intermediate.