Selective oxidation of p-xylene to terephthaldehyde (TPAL) on W-Sb oxides

ABSTRACT Selective oxidation of p-xylene to terephthaldehyde (TPAL) on W-Sb oxide catalysts was studied. While WO 3 was active in p-xylene conversion but non-selective for TPAL formation, addition of Sb decreased the activity in p-xylene conversion but increased TPAL selectivity significantly. Structure change was also induced by Sb addition. Evidences from various characterization techniques and theoretical calculation suggest that Sb may exist as various forms, which have different p-xylene adsorption property, reactivity toward p-xylene and TPAL selectivity. Relative population of each species depends on Sb content.