Vattikonda Venkat Rao

Alkylation of phenol with methanol over molybdenum oxide supported on NaY zeolite

A series of MoO3/NaY catalysts were prepared with Mo loadings ranging from 2 to 16 wt% and characterized by X-ray diffraction (XRD), BET specific surface area and temperature-programmed desorption (TPD) of ammonia. XRD results revealed that the crystallinity of NaY zeolite was found to decrease with increase in Mo loading in the catalysts. The total acidity measured by ammonia TPD of the catalysts was found to decrease with increase in Mo loading. The catalytic properties were evaluated for the vapor phase alkylation of phenol with methanol and the results were correlated with results obtained from different characterization techniques. The conversion of phenol decreases as Mo loading increases in the catalyst. With increase in Mo loading on NaY zeolite the selectivity for the formation of C-alkylated compounds was decreased. However, the selectivity towards the formation of O-alkylated products was increased.

Vapour phase ammoxidation of toluene over vanadium oxide supported on Nb2O5-TiO2

Vanadium oxide catalysts with V2O5 loadings ranging 1 to 9% (w/w) supported on 1∶1 wt% Nb2O5–TiO2 mixed oxide have been prepared by the wet impregnation method. The calcined samples were characterized by X-ray diffraction (XRD), pulse oxygen chemisorption and temperature programmed desorption (TPD) of NH3. Dispersion of vanadia was determined by oxygen chemisorption at 643 K in a dynamic method. At low V2O5 loadings, vanadia is found to be present in a highly dispersed state. X-Ray diffraction results also suggest that vanadium oxide exists in a highly dispersed state at lower loadings and in a crystalline V2O5 phase at higher vanadia loadings (5 wt% and above). The dispersion of vanadia was found to decrease with V2O5 loading due to the formation of V2O5 crystallites. The catalytic properties were evaluated for the vapor phase ammoxidation of toluene to benzonitrile and correlated with characterization results.

Ammoxidation of 3-picoline over vanadia-molybdena catalysts supported on γ-Al 2 O 3

Ammoxidation of 3-picoline to nicotinonitrile was carried out on V2O5-MoO3 catalysts supported on γ-alumina. The results suggest that the addition of MoO3 improves catalytic properties during ammoxidation.