π-Bonded Olefines and Olefine Hydrogenation

Abstract

ALTHOUGH the catalysed hydrogenation of ethylene and other olefines has been a favourite reaction for investigation for many years, it has, in general, proved vastly more complicated than would appear from the simple stoichiometry of the reaction. Continuing investigations are, however, giving more insight into the numerous possible elementary steps involved in the overall reaction. In a recent review¹ Bond has emphasized the role of π-bonded olefines in the metal-catalysed hydrogenation of unsaturated compounds, although he points out that there is no evidence as to whether say π-bonded ethylene will react with hydrogen to give ethane directly, or whether a σ-diadsorbed olefine is a necessary intermediate.