Activity and sulfur resistance of co-impregnated bimetallic PdNi/γ-Al2O3 catalysts during hydrogenation of styrene

Pyrolysis gasoline (PyGas) is an unstable byproduct of the pyrolysis naphtha and other hydrocarbons for production olefins. PyGas stabilized by hydrogenation at mild conditions. The styrene to ethylbenzene considered a model test reaction studying selectivity catalysts because it has slowest rate conversion. catalytic activity two bimetallic co-impregnated Pd–Ni supported on γ-alumina were assessed compared those commercial monometallic Pd catalyst (AXENS LD265). laboratory-prepared had different metal content Pd:Ni atomic ratios (1:1 1:7). Catalytic tests selective made in batch stirred tank reactor continuous fixed bed trickle reactor. sulfur resistance semicontinuous condition, was means same operational conditions using thiophene as poison compound. support, LD265 further characterized N2 chemisorption, EPMA, OM, ICP elemental analysis, temperature programmed reduction, XPS X-Ray diffraction. results indicated presence species: Pd0, Pdδ+, Ni0 NiO. lab-prepared found be active (both system). During evaluations, intermediate level that lied between values corresponding catalysts: PdNi(1:1) $$ \gg > PdNi(1:7). free pattern conversion function contact time are quite similar catalyst, though slightly better PdNi(1:1). After 90 min order was: On hand, during (with 300 pp thiophene), initial rates decreased, pointing poisoning sites thiophene. higher than PdNi(1:7) or poisoned both more resistant attributed Pd0 Pdn+/Nim+ species favored respectively, homolytic cleavage H–H bond adsorption styrene. would associated with Cl/Al surface ratio this (electronic effect) electrodeficient (Pdxδ+OyClz) prevented steric hindrance (geometrical effect large species) electronic effects.