Reactions of alkenes and the equilibration of hydrogen and deuterium on zirconia

Abstract

The hydrogenation of various alkenes, the equilibration of H₂/D₂ and the isomerisation of some C₆-alkenes have been studied over a range of temperatures on zirconia catalysts. Products from the reaction of some of the alkenes with deuterium were examined by ²D n.m.r. spectroscopy. The rate of hydrogenation varied only to a small extent with the nature of the alkene, apart from some steric hindrance with some of the C₆-compounds, and the supply of hydrogen to the surface appeared to be rate-determining. Reactions of alkenes with deuterium below 400 K gave D₂-alkanes. As the temperature was raised, exchange of alkene was observed to an increasing extent, and the location of the deuterium atoms in the products provided evidence of possible mechanisms.