Ammoxidation of 3-Picoline over V2O5/TiO2 Catalysts: Effects of TiO2 Supports on the Catalytic Performance

Abstract

A series of V2O5/TiO2 catalysts were prepared by wet impregnation, and these prepared catalysts were characterized by XRD, N2 adsorption-desorption, H2-TPR, and TEM techniques and used in the selective ammoxidation of 3-picoline to 3-cyanopyridine. The effects of TiO2 supports on the catalytic properties of the resulting catalysts for the ammoxidation of 3-picoline to 3-cyanopyridine were investigated in detail. It is found that the V5+/V4+ transformation during ammoxidation is more favorable than the V5+/V3+ transformation for the selective ammoxidation of 3-picoline to 3-cyanopyridine. The V2O5/TiO2 catalysts prepared from the nanosized TiO2 particles as supports show a high activity for the direct oxidation of 3-picoline by air, resulting Subscript text Subscript textin a low selectivity for 3-cyanopyridine. This could be due to the fact that the active species vanadium oxides could be only supported on the external surface of the nano-sized TiO2 particles with very minor contact area, leading to the weak interactions between active species and support.