Heterogeneous Catalysis in Organic Chemistry: Effect of Hydrogen Presaturation of the Catalyst in the Hydrogenation of Olefins

Article abstract of DOI:10.1021/jo00326a003

A "time-lapse" procedure has been used to investigate the first few turnovers occurring in the hydrogenation of a double bond.Initial exposure of a platinum catalyst to either hydrogen or an olefin made no difference in the outcome of the reaction but initial treatment of a palladium catalysts with an olefin resulted in a change in its reaction characteristics.Presaturation of either the platinum or palladium catalyst with hydrogen results in the storage of a relatively large amount of hydrogen in the support by the process of spillover.By reverse spillover this hydrogen can migrate to the active sites on the catalyst and, thus, be avai lable for reaction in the event that the site does not acquire hydrogen from the reaction medium rapidly enough.