HYDROGENATION OF ACETYLENE ON PALLADIUM

The activity of palladium towards acetylene hydrogenation is affected by the formation of a palladium hydride. Hydrogenations have been carr ied out on a polycrystalline sample of palladium pretreated by two dif ferent procedures in order to compare the resulting activities; format ion of a superficial hydride appears to be a necessary primary step to ensure good activity of the catalyst. The selectivity to ethylene is always very high, around 90%. The hydrogenation proceeds through consu mption of hydrogen from the hydride phase.