Effect of Adsorbed Hydrocarbon on the Catalytic Exchange of n-Butane and Deuterium on Tungsten Films

Abstract

The exchange of n-butane with deuterium is catalyzed by tungsten films at temperatures below 250 K; the reaction involves mainly simple exchange with no evidence of self-poisoning. The adsorption of butane on tungsten at temperatures from 273 to 423 K gives strongly adsorbed hydrocarbon species which reduce the rate of the subsequent exchange at 273 K by factors of from 10 to 2000, the effect increasing with the adsorption temperature. Only a fraction of these adsorbed species is easily rehydrogenated. Some results for comparison arc obtained with adsorbed but-l-ene, neopentane or methane.