Connection between macroscopic kinetic measurables and the degree of rate control

Abstract

Catalytic reactions are commonly characterized by measuring reaction orders and apparent activation energies. In the present work, these macroscopic measurables are related to the degree of rate control (χ_i), which describes how the overall kinetics is influenced by the elementary reactions. The reaction orders are found to be χ_i-weighted sums over the microscopic rates, derived with respect to pressure. Similarly, the apparent activation energy is shown to be a sum over the individual reaction-energy-barriers, weighted by χ_i. The results couple macroscopic kinetics to the microscopic scale, which can facilitate analysis of catalytic reaction kinetics.