SELECTIVE HYDROGENATION OF CYCLOPENTADIENE OVER SUPPORTED METAL-CATALYSTS

The selective hydrogenation of cyclopentadiene to cyclopentene has bee n studied in the liquid phase using Pd and Pd-Me/Al2O3 bimetallic cata lysts (Me = Mn, Ni, Co, W). The highest activity was obtained with Pd- Co and Pd-W/Al2O3. For these catalysts, no hydrogen or CO chemisorptio n was detected although Pd could be seen by XPS at 335.8 eV; it is con sidered that new species, more active for the selective hydrogenation of cyclopentadiene, appeared at the catalyst surface. The sulfur resis tance towards thiophene has also been studied. It was observed that th e highest sulfur resistance is coincident with the highest activity. X PS analysis shows that the poisoning species is thiophene adsorbed on the catalyst surface.