PALLADIUM-BASED DIFFUSION MEMBRANES AS CATALYSTS IN ETHYLENE HYDROGENATION

Pd-23 at% Ag and Pd-7.8 at% Y hydrogen-diffusion membranes were (1) prepared by argon-arc melting of the constituent elements, (2) characterised, (3) examined for hydrogen permeation and (4) used as catalysts in ethylene hydrogenation reactions. Ethylene was self-hydrogenated on the membrane surfaces in the absence of permeate hydrogen. The hydrogenation with and/or without the permeate hydrogen was carried out in the temperature range 100-450-degrees-C at ethylene pressures of 1.0-1.5 bars and differential pressures across the membrane in the range 1.0-6.8 bars. Mainly C1-C4 hydrocarbons and up to 60% conversion of ethylene to products were obtained.