Preparation, characterization and catalytic activity of WO3 supported on sulfated tin oxide catalysts

Catalytic application toward esterification of propionic acid with n-butanol was tested and the effect of various parameters, i.e., reaction temperature, reactant molar ratio, weight of the catalyst, WO3 loading and calcination temperature was also investigated. The highest conversion level was found for products loaded with 25 wt.%WO3 and calcined at 400 °C. Although both of Brønsted and Lewis acid sites are responsible for the reaction, the former acid sites found more effective on catalyzing the esterification reaction.