NONEQUILIBRIUM EFFECTS IN THE LIQUID-PHASE CATALYTIC-HYDROGENATION

Catalytic hydrogenation in the liquid-phase over supported metal catal ysts at high hydrogen pressures can be described by the zero order in respect to all components. The reaction mechanism which involves forma tion of intermediate complexes including hydrogen and organic compound is discussed. The reaction rate in the region of zero orders is deter mined by the isomerisation rate of these complexes. Experimental data presented indicate that the pre-exponential factor in Arrhenius equati on is essentially less then expected from the absolute rate theory. Th ese observations are explained based on the model of an anharmonic osc illator.