Titanium-vanadium-tin comprising catalyst and process for the preparation of phthalic anhydride

摘要

Disclosed are catalytic compositions comprising oxides of titanium vanadium and tin which are suitable for the production of phthalic anhydride by oxidizing o-xylene and/or napthalene in the gas phase. The catalysts exibit excellent activity and selectivity. The catalyst comprise 2 to 15% by weight (calculated as V₂O₅) of vanadium, from 1 to 15% by weight (calculated as SnO₂) of tin and further comprise from 70 to 97% by weight (calculated as TiO₂) of titanium. In a preferred embodiment the catalyst of the invention comprise up to 5% by weight (calculated as M₂O) of at least tine alkali metal preferably lithium, potassium or rubidium, and more preferably cesium. In an even more preferred embodiment, cesium is present in an amount of from 0.01 to 2% by weight (calculated as Cs₂O).