ACETYLENE DEUTERATION IN THE PRESENCE OF [ETHYLENE-C-14

The selective deuteration of 2.1 kN m-2 of a mixture containing 90% acetylene and 10% [14C]ethylene in the presence of 8.4 kN m-2 deuterium gas was studied at 273 and 303 K over Pd black catalyst. Product samples were separated by gc and the column effluent was analyzed by quantity, radioactivity, and deuterium contents of the individual peaks. The double labeling method related surface reaction steps and the adsorption/desorption properties of intermediate at the same activity level of the catalyst. Thus, disparities resulting from studies of these parameters in separate experiments were eliminated. The observed overall reaction network in the adsorbed phase is {A figure is presented} Ethylene desorption was fast compared to its further reaction and its readsorption occurred only when the amount of acetylene decreased below a certain level. Initially acetylene monopolized the site, and the sole process was {A figure is presented} Subsequently, after acetylene partial pressure diminished, ethylene could competitively adsorb, and {A figure is presented} occurred. © 1979.