Physico-chemical characteristics of sulfated mixed oxides of Sn with some rare earth elements

A series of binary mixed oxides of tin with three rare earth elements viz. La, Ce and Sm were prepared by co-precipitation method and sulfate treatment was performed by treating the mixed hydroxides with sulfuric acid or ammonium sulfate. The physicochemical characterization has been done by XRD, BET-SA, SEM, EDX, TG-DTA and IR spectroscopy. Adsorption of n-butylamine was used to probe the acidic properties of the catalysts. The strength and distribution of acid sites depend on the mixed metal oxide composition, as well as on the preparation method. The rare earth modified sulfated tin oxide catalysts are more active in the oxidative dehydrogenation of cyclohexanol and cyclohexane, compared to the corresponding mixed oxide systems and sulfated tin oxide. Among the different sulfated oxide systems investigated, cerium promoted catalysts displayed a better selectivity towards dehydrogenation products.