Ethylene Hydrogenation Catalyzed by Molybdenum Nitride

Abstract

Ethylene hydrogenation catalyzed by molybdenum nitride has been studied at -78°C. The rate of reaction was O.6 th and zero order with regard to hydrogen and ethylene, respectively. An average value of the isotope effect kllIkp=1.8 was observed. The reaction of H₂D₂ mixtures with ethylene and the reaction of H₂ with C_2CH₄-C_2CD₄ mixtures were also carried out at -78°C. Isotopic mixing of hydrogenes in ethylene was quite rapid and reached an equilibrium in 10 minutes both in the presence and absence of hydrogen. While the H₂-D₂ exchange was retarded by ethylene. Hydrogen added to ethylene was not considered to undergo isotopic exchange before the reaction with ethylene, because the isotopic composition of product ethane (d, , d and d2 species) was close to that of the reactant hydrogen (H₂, HD, and D_O). From these results possible mechanisms for the hydrogenation of ethylene are proposed.