Application of the De Donder Relation to the Mechanism of Catalytic Reactions

The principle of microscopic reversibility at equilibrium is often invoked in the context of the feasibility of postulated kinetic mechanisms. In this context, it is argued that the De Donder relation Av ≥ 0, relating the affinity A and the net rate v of a chemical reaction, appears to be particularly incisive, as it clearly applies to nonequilibrium systems, at the steady state or the quasi-steady state. In particular, when reactions or elementary steps are involved in closed cycles, application of the De Donder relation leads to informative restrictions concerning postulated mechanisms.