Continuous gas–liquid aerobic oxidation of toluene catalyzed by [T(p-Cl)PPFe]2O in a series of three stirred tank reactors

The liquid-phase catalytic aerobic oxidation of toluene by [T(p-Cl)PPFe]2O was studied in a series of three stirred tank reactors. The effects of operation mode (including semi-batch and continuous operation), reaction temperature, catalyst concentration, average residence time, and air flow rate on the oxidation process were examined. The experimental results showed that continuous oxidation had no advantage over the total yield and selectivity of benzaldehyde and benzyl alcohol in comparison with semi-batch oxidation. And the reaction temperature was the most significant factor influencing on continuous oxidation of toluene. It is also found that adopting sequentially decreased temperature in the three series reactors could improve the yield and selectivity of benzaldehyde and benzyl alcohol in this process. Under which at the higher conversion of toluene, the total yield to benzaldehyde and benzyl alcohol increased 17.05% or 43.62% respectively in comparison with adopting sequentially increased or same temperature in the three series reactors.