Mechanism of thermal decomposition of salts of carboxylic acids

Abstract

1. The thermal decomposition of Ca, Ba, Li, Rb, Ag, and Cu acetates at 473–873°K was analyzed thermodynamically. In all cases apart from Ag and Cu acetates, and regardless of the nature of the acid radical, the decomposition of the salt to the anhydride and the metal oxide was thermodynamically forbidden. The results of the calculations are confirmed by experimental data. 2. The characteristics of the topochemical decomposition of Ca, Ba, Cd, Mg, and Zn acetates were examined: they were the lack of an induction period, the fact thatn in Erofeev's equationα=1−e−kτn is close to unity, the planar form of the reaction nucleus, and the fact that the reaction proceeds in the kinetic region. The decomposition proceeds by the growth of initial centers present in the substance and the activation energy determined experimentally is the activation energy of the growth of the reaction nuclei. 3. In the case of the decomposition of Li, Na, K, and Rb acetates, which occurs in the melt, an interpretation is given for the effect of the nature of the metal on the activation energy and pre-exponent. The effect of thermodynamic factors on the course of the change in activation energy is discussed.