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Olefin Purification and Selective Hydrogenation of Alkynes with Low Loaded Pd Nanoparticle Catalysts

“…Therefore, on the basis of activity and selectivity all the prepared catalysts were comparable or better than the Lindlar catalyst for hydrogenation of alkynes. The activity and selectivity results suggest a better synergism between the Pd nanoparticles and the supports, probably because of an easier dissociation of hydrogen over the metal center, as reported by Jackson et al In these reactions, the initial reaction rate is supposed to be related to the dissociative adsorption of hydrogen . It is well-known that during hydrogenations, metallic centers rich in electrons can cleave the H–H bond by means of the interaction of a filled d metal orbital with the empty σ antibonding molecular orbital of H 2 .…”

“…Jackson et al ,− studied the hydrogenation of alkynes/alkenes mixtures. They focused systematically on the selective hydrogenation of higher molecular weight alkynes, obtaining several important results about the reaction kinetics. − Murugesan et al studied the elimination of phenylacetylene in the presence of styrene. Using Ni-fructose/SiO 2 -800, 0.5 mmol of phenylacetylene (5%) were hydrogenated in the presence of 9.5 mmol of styrene (95%) at 353 K with 1 MPa H 2 pressure.…”

Active coke: Carbonaceous materials as catalysts for alkane dehydrogenation

“…Elsewhere, the hydrogenation of carbon-carbon double bonds over supported metal catalysts has been shown to be strongly dependent upon the nature of any deposited carbonaceous material [65]. Such reactions have been suggested to proceed, at least in part, through the transfer of hydrogen from an adsorbed hydrocarbonaceous overlayer onto which the reactant is adsorbed [66,67]. Furthermore, carbon deposited during reaction plays a key role in the hydrogenation of alkynes over Pd catalysts, forming a catalytically active Pd-C x surface phase [68,69].…”

C-5 alkene hydrogenation: Effect of competitive reactions on activity and selectivity

“…A number of recent studies have investigated competitive hydrogenation reactions, such as phenyl acetylene and styrene on Pd/C [5], benzonitrile on higher alkynes [6], 1-pentyne and 2-pentyne [7,8] and competitive reactions of C6 and C8 species over palladium and platinum catalysts [9]. Various effects have been demonstrated in these studies, from rate depression of one or more of the competing reactants, to a rate enhancement of both reacting species.…”