Deactivation and regeneration of sulfur-poisoned supported palladium complexes

The deactivation by thiophene of the [PdCl2(CH3SOCH3)(2)] and the [PdCl2(NH2(CH2)(12)CH3)(2)] complexes supported on gamma-Al2O3, during the selective hydrogenation of styrene has been studied at 353 K and 10 kg cm(-2). Although both complexes are deactivated when the feed contains more than 300 ppm thiophene, the [PdCl2(NH2(CH2)(12)CH3)(2)] supported complex is more sulfur resistant. Thiophene is partially eliminated by hydrogen treatments at 353 K and 10 kg cm(-2) thereby indicating that thiophene has not substituted, at least totally, the complex ligands.