INFLUENCE OF SURFACE SUPPORT PROPERTIES ON THE LIQUID-PHASE SELECTIVEHYDROGENATION OF PHENYLACETYLENE ON SUPPORTED NICKEL-CATALYSTS

The role of textural and acid-base properties of supports on metal-sup port interaction effects has been evaluated through the results obtain ed in the liquid-phase selective hydrogenation of phenylacetylene carr ied out on 20 wt% supported nickel catalysts. SiO2, Al2O3, AlPO4, acti ve carbon and a natural sepiolite were used as supports. The effects o f Ni-Cu alloying were also studied. The relative adsorption constants, K-T,K-D, and the relative reactivities, R-T,R-D. obtained in the cons ecutive hydrogenation process, were used to follow the effects of any electron transfer between the nickel atoms and acid-basic sites on the support surface. Structural defects of supported nickel crystallites were determined by X-ray diffraction line broadening analysis and used for measuring the participation of geometric effects of supported nic kel crystallites in the catalytic activity. Results obtained may be be tter explained within a framework of simultaneous electronic and struc tural metal-support interaction effects.