REGENERATION OF A SULFUR POISONED PD/AL2O3 CATALYST DURING THE SELECTIVE HYDROGENATION OF STYRENE

Deactivation by thiophene and the regeneration of a commercial Pd/Al2O3 catalyst was studied with reference to the contribution of the support to the loss and subsequent recovery of catalyst selectivity. The selective hydrogenation of styrene to ethylbenzene was taken as a test reaction. The electronic state of palladium during the poisoning/regeneration process was followed by XPS (X-ray photoelectron spectroscopy). The catalyst was regenerated by eliminating the poison in the feed or by ex-situ treatments at different temperatures or hydrogen pressures. Sulfur is partially and irreversibly adsorbed on the metal and the catalyst activity could never be completely renewed. The XPS results suggest that the electronic properties of palladium are modified in the poisoning/regeneration process. © 1990.