Extended kinetic approach to reversible thermal decomposition of solids: A universal description considering the effect of the gaseous product and the kinetic compensation effect

The kinetics of the reversible thermal decomposition of solids, simplified as A(s) B(s) + C(g), is universally described, as a function of temperature (T), degree of reaction (alpha), and partial pressure of gaseous product (p(C (g))) concerning the equilibrium pressure (Peq(T)) of the reaction, with the aid of an accommodation function (h (p(C(g)), Peq(T))). The kinetic curves of the reaction at different p(C(g)) values form a specific surface in the extended three-dimensional kinetic coordinate (T-1, alpha, ln[(d alpha/dt)/h(p(C(g)), Peq(T))]). The coordinate surface is characterized in terms of isoconversional and isothermal kinetic relationships. The apparent Arrhenius parameters that characterize the coordinate surface are related to the intrinsic Arrhenius parameters by considering the thermodynamic parameters of the reaction. In addition, all sets of Arrhenius parameters determined using the extended kinetic approach are correlated with the kinetic compensation effect. Herein, the extended kinetic approach was demonstrated, as exemplified by the thermal decomposition of CaCO3.