The relation between surface acidity and MoO3:Al2O3 ratio on the ternary mixed oxide catalysts for the conversion of propan-2-ol.

Abstract

In this study, ternary mixed oxide catalysts containing Al2O3-MoO3-MgO and Al2O3-MoO3-WO3 were prepared with a changing ratio of MoO3:Al2O3 between 0.05 and 20.00. All catalysts showed 100% selectivity towards propene during the conversion of propan-2-ol at temperatures between 220 and 400 °C. The catalysts prepared from WO3 possessed very strong acid sites, which cause higher catalytic activity than catalysts prepared from MgO. Besides, the ratio of MoO3:Al2O3 was found to be directly proportional to the conversion yield for all catalysts. XRD results show that whole MgO reacted with Al2O3 and MoO3 to form amorphous MgMoO4 and MgAl2O4 phases during catalyst preparation. Furthermore, WO3 reacted only with Al2O3 to form Al2(WO4)3 and WO3 phase was also detected in the final product. The higher surface acidity and catalytic activity of Al2O3-MoO3-WO3 catalyst referred to this WO3 phase within the structure.