Hydrogenolysis of ethane was investigated on nickel powder catalyst from 170 to 320 °C. The reaction was first order with respect to ethane and it was inhibited by hydrogen at sufficiently low temperature whereas at high temperature it was independent of hydrogen pressure. This behaviour as well as the relation among the energies of activation of ethane exchange, methane exchange and ethane hydrogenolysis (20, 30 and 39 kcal mole-1, respectively) give further evidence for the validity of the kinetic picture described by Sinfelt and Taylor. The application of deuterium and tritium in place of hydrogen offers new information for the mechanism of hydrogenolysis. The distribution of deuterated methane shows that the initial step for ethane exchange and hydrogenolysis is probably common and the adsorption with CC bond rupture may be ruled out. In comparison with methane-deuterium exchange under the same condition, clear evidence was obtained that methane desorption is fast and may not be a ratelimiting step. For this direct proof has not been found in literature. An explanation is given for the change in distribution of deuterated methane formed in the hydrogenolysis taking place with variation of temperature and activity of catalyst.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry