The activation energies of the same process are often reported to have different values, which are usually explained by the
differences in experimental conditions and sample characteristics. In addition to this type of uncertainty, which is associated
with the process (ΔEprocess) there is an uncertainty related to the method of computation of the activation energy (ΔEmethod). For a method that uses fitting single heating rate data to various reaction models, the value of ΔEmethod) method is large enough to explain significant differences in the reported values of the activation energy. This uncertainty
is significantly reduced by using multiple heating rate isoconversional methods, which may be recommended for obtaining reference
values for the activation energy.
presents the model-free kinetic approach in the context of the traditional
kinetic description based on the kinetic triplet, A, E, and f(α)
or g(α). A physical meaning and interpretability
of the triplet are considered. It is argued that the experimental values of f(α) or g(α)
and A are unlikely to be interpretable in the respective terms of the reaction
mechanism and of the vibrational frequency of the activated complex. The traditional
kinetic description needs these values for making kinetic predictions. Interpretations
are most readily accomplished for the experimental value of E
that generally is a function of the activation energies of the individual
steps of a condensed phase process. Model-free kinetic analysis produces a
dependence of E on α that is sufficient
for accomplishing theoretical interpretations and kinetic predictions. Although
model-free description does not need the values of A
and f(α) or g(α),
the methods of their estimating are discussed.
A nonlinear algorithm has been suggested to increase the accuracy of evaluating the activation energy by the integral isoconversional method. A minor modification of the algorithm has made it possible to adapt the isoconversional method for an arbitrary variation of the temperature. This advanced isoconversional method allows for trustworthy estimates of the activation energy when the thermal effect of a reaction makes the temperature of a sample deviate from a prescribed heating program.
The paper gives a quantitative comparison of two methodological approaches to the solution of the inverse kinetic problem: the traditional approach and the nontraditional approach suggested by the authors. It is shown that the amount of information (in the sense of Shannon) obtained within the scope of the nontraditional approach is always greater than that obtained with the use of the traditional approach.
This review deals with the choice of a method of solving the inverse kinetic problem (IKP) which would provide the most definite description of the process under conditions of ambiguity. Two fundamentally different methodologies are possible for the IKP solution: one is based on the principle of unambiguous description (discrimination), while the other relies upon the complementarity principle (generalized descriptions). Specific IKP solution methods have been classified, the methodological differences being taken into account. In the first part of this review, general and special limitations in discrimination of formal models have been analysed.