Abstract
The hydrogenation of ethylene and propylene was studied in the presence of a 5 % Pt/carbon catalyst suspended in water. In the hydrogenation of the respective olefin, the rate-controlling steps affecting the overall reaction rate were first examined. As for the results, the hydrogenation rates were found to be predominantly controlled by the mass transfer of olefin from the gas phase to the catalyst particles in the region of excess hydrogen, while in the region of excess olefin they were influenced not only by the mass transfer but also by the combination of the chemical reaction and the pore diffusion. For the latter region, an intrinsic kinetic expression was derived assuming the adsorption of molecular hydrogen as the rate-determining step.
For the competitive hydrogenation of both olefins, the selectivity, defined as the ratio of the reaction rate of propylene to that of ethylene, was examined on the basis of the results obtained in the hydrogenation of the individual olefin.
