Oxidative Dehydration of Glycerol over Molybdenum- and Vanadium-Based Catalysts

Surplus of glycerol production from the biodiesel industry has led to the search for glycerol conversion routes, the most common of which are dehydration and oxidative dehydration. Vanadium and molybdenum oxides were supported on γ-Al2O3 and their properties were analyzed through several characterization techniques, showing that the acidity increases after addition of oxides and that in the catalyst with vanadium and molybdenum there is decrease in the band referring to V5+, responsible for sequential oxidation to CO2. The effect of the metal oxides on catalytic activity and stability during oxidative dehydration of glycerol to acrolein was investigated and correlated with chemical composition, acidity, and textural properties. Moreover, the global reaction, turnover frequency (TOF), and activation energy were determined. Catalyst performance and stability were found to depend on acidity and the supported metal with larger residence times (W/F) favored acrolein formation over COx. In addition, metal oxides decreased catalyst deactivation via coke oxidation.