Selective hydrogenation of acetylene and hydrodechlorination of 1,2-dichloroethane over palladium bimetallic catalysts

Selectivity and conversion to ethylene were studied in the following reactions: hydrogenation of acetylene and hydrodechlorination of 1,2-dichloroethane. These reactions correspond to a class of reactions, such that A → B → C. In order to maximize the concentration of B, the ratio of the successive rate constants must be considered. This has been accomplished using Pd as the primary metal, which is clustered with a group IB metal. The group IB metal serves as a selectivity and conversion promoter. Gamma-alumina is the most effective support for this reaction. However, silica is used as the support for the hydrodechlorination reaction because the HCl evolved during the reaction poisons alumina.{09}The addition of the group IB metal has the additional advantage of decreasing the deactivation of the catalyst. Both reactions are studied at various temperatures and metal loading.; Two temperature maxima were observed in the selective hydrogenation of acetylene reaction. It is theorized that the formation of a carbonaceous species on the surface of the catalyst enhances the conversion and selectivity to ethylene. Bimetallic clusters were observed through TEM/EDS analysis. The bimetallic catalysts for the hydrodechlorination of 1,2-dichloroethane were found to be more selective to ethylene. Deactivation was decreased over the bimetallic catalysts. Reaction mechanisms have been proposed for the bimetallic catalysts.