V. Venkat Rao

Influence of V2O5 content on ammoxidation of 3-picoline over V2O5/AlF3 catalysts

V2O5/AlF3 catalysts with V2O5 loadings ranging from 2 to 15 wt% were prepared by the conventional wet impregnation method, using nonporous AlF3·3H2O sample as the support for impregnating NH4VO3. It was found that the catalysts evolve porous structures upon calcination at 723 K. The influence of V2O5 content was studied on ammoxidation of 3-picoline on the reduced catalysts. The catalyst with 15 wt% V2O5 exhibited the highest selective ammoxidation acitivity towards nicotinonitrile. The XRD and oxygen chemisorption studies revealed that vanadia is in a highly dispersed state in the catalysts.

Reactivity of V2O5/MgF2 Catalysts for the Selective Ammoxidation of 3-Picoline

V2O5/MgF2 catalysts with V2O5 contents ranging from 2.1 to 15.7 wt% were prepared, and the influence of the V2O5 content of the V2O5/MgF2 catalyst on the structure and activity for the ammoxidation of 3-picoline was investigated. XRD data indicate that V2O5 is in a highly dispersed state though segregation of V2O5 into tiny crystallites occurs at and above 8 wt% V2O5. The 3-picoline ammoxidation activity increased with an increase in V2O5 content due not only to the species arising out of interaction of V2O5 and MgF2, but also to the presence of V2O5 microcrystals in the catalysts.

Influence of molybdena on the dispersion and activity of vanadia in V2O5/γ-Al2O3 catalysts

The influence of molybdenum oxide on the dispersion and activity of vanadium oxide supported on alumina was investigated. A series of MoO3 catalysts were prepared using monolayer V2O5/γ-Al2O3 catalysts by impregnation method. The catalysts were characterized by X-ray diffraction and oxygen chemisorption at −78 °C. The catalytic properties were evaluated for the vapour-phase oxidation of methanol. The addition of MoO3 to V2O5/γ-Al2O3 results in the decrease of dispersion of vanadia and also the activity for the oxidation reaction. However, the selectivity of formaldehyde was found to increase with MoO3 loading indicating that MoO3 created additional sites for partial oxidation reaction.