CHARACTERIZATION AND ANILINE ALKYLATION ACTIVITY OF VANADIA AND SILICA-SUPPORTED VANADIA CATALYSTS

Vanadia and silica-supported vanadia have been characterized by XRD, ESR and chemisorption of oxygen at low temperature (COLT) to assess the nature of the vanadia dispersion on the support. Aniline alkylation studies on the effect of temperature and contact time on the conversion and selectivity of the products reveal that supported vanadia is significantly more active than vanadia and SiO2. The alkylation reaction proceeds through consecutive formation of secondary, tertiary and C-alkylated anilines. Reaction conditions can be favourably modified to get selectively N-ethylaniline over vanadia-silica. An attempt has been made to correlate dispersion and catalytic activity with the active species.