Thermochemical model in kinetics of heterogeneous reactions: 100-year jubilee

Abstract

The milestones in the development of the thermochemical model (TM) in kinetics of heterogeneous reactions over 100 years after publication in 1913 of the Langmuir equation, \( J\; = \;MP/\sqrt{2\pi MRT} \), were considered. However, the systematic development of TM was begun only in the early 1980s. Among the milestones of this latter period, which passed with the participation of the author, the most important were: the extension of Langmuir equation to dissociative vaporization of compounds and identification of two modes of vaporization (equimolar and isobaric); the discovery of the mechanism of congruent dissociative vaporization; the application of the third-law method to determination of the E parameters (“activation energies” in the Arrhenius equation) and formulation of theoretical and experimental evidence for the absence of activation effect in decomposition reactions. During this period, the new theory was applied to the interpretation of many unsolved problems in heterogeneous kinetics. In the majority of cases, the interpretation is reliably supported by agreement between theory and experiment. The traditional kinetic theories based on the activation effect (the classical Arrhenius theory, as well as the collision and transition state theories) appeared fruitless in this respect.