Mechanisms of hydrogenation. Part VII. Kinetic aspects of homogeneous and heterogeneous hydrogenation

Abstract

The kinetics of hydrogenation of an olefin with various soluble platinum, palladium, ruthenium, or iridium complexes indicate two modes of reaction: (a) of the olefin with metal hydride at low olefin concentration and (b) of hydrogen with the complexed olefin at higher olefin concentrations. The course of heterogeneous hydrogenation of an acetylene is shown to depend on the order in which the hydrogen and acetylene are introduced to the catalyst. The steric course of hydrogenation of 3-oxo-Δ^4,5 steroids at palladium is discussed in terms of adsorption or hydrogen-transfer as the kinetically controlling stage.