Mechanism and Selectivity of the Hydrogenation of Alkadienes to Alkenes in the Presence of Group VIII Metals.

Similarly to platinum catalysts, also rhodium, iridium and nickel catalyst exhibit low selectivity in the hydrogenation of conjugated alkadienes. Data area presented which show that this low selectivity is caused by the fact that these catalysts have no ability to stabilize pi -allyl adsorbed intermediates. Only palladium and cobalt catalysts demonstrate this ability and that is why that show excellent selectivity in the conversion of alkadiene to respective alkenes by hydrogenation.