Selective oxidation of isobutene over bismuth molybdate catalyst

Initial rate data were used to study the kinetic behaviour of the selective oxidation of isobutene to methacrolein over γ-bismuth molybdate at low conversion levels. The investigation was carried out in a differential flow reactor over the temperature range 623 to 729 K. The data were fitted to a number of models based on Mars-van Krevelen and Langmuir-Hinshelwood mechanisms, and also to the empirical model known as the power rate law model. The preferred model for the formation of methacrolein is found to be the redox model with non-dissociated oxygen involved in the reoxidation step. The activation energy for catalyst reduction was found to be 52 kJ/mol while the value for catalyst reoxidation was 142 kJ/mol.