Characterization and catalytic properties of molybdenum oxide catalysts supported on ZrO2–γ-Al2O3 for ammoxidation of toluene

Abstract

Molybdenum oxide catalysts with MoO₃ loadings ranging from 6.6 to 25 wt% supported on ZrO₂–γ-Al₂O₃ (1 : 1 wt%) mixed oxide were prepared by a wet impregnation method. The catalytic behavior of catalysts in the toluene ammoxidation reaction was investigated in a lab-scale tube reactor at 400 °C. The catalytic performance of MoO₃/ZrO₂–γ-Al₂O₃ was dependent on the catalyst compositions and reaction temperature. MoO₃ (20.0 wt%) ZrO₂–γ-Al₂O₃ exhibited a good toluene oxidation; over this catalyst, the selectivity to benzonitrile reached 67.0% with a toluene conversion of 68.5% at 400 °C, while the selectivity to benzaldhyde was 24.4% with a toluene conversion of 68.5% at 400 °C. The catalysts were characterized by various techniques, such as N₂ sorption, FTIR, SEM and XRD.