Compensation Effect in Heterogeneous Catalytic Reactions including Hydrocarbon Formation on Clays

Abstract

A SERIES of comparable reactions is said to exhibit compensation behaviour when the Arrhenius plots show systematic variations of the activation energy (E) and the pre-exponential factor (A) according to the expression Many examples of such behaviour have been reported for diverse reaction systems, but hitherto no explanation of the effect has been generally accepted. Indeed, it has been suggested^1–3 that obedience of data from a sequence of reactions to equation (1) may arise through the method of analysis of the kinetic measurements or it may be an artefact. But before compensation behaviour is dismissed as a phenomenon of little theoretical significance, we suggest that in at least one field, heterogeneous catalysis, obedience to equation (1) may be considered to result from a useful mechanistic model. Many examples of compensation behaviour among reactions catalysed by solids have been reported and Bond⁴ has discussed the theoretical implications. The present preliminary report describes a further sequence of surface rate processes which exhibit the compensation effect and proposes a model to explain these observations.