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.
Authors:Maria J. F. Costa, Antonio S. Araujo, Edjane F. B. Silva, Mirna F. Farias, Valter J. Fernandes Jr., Petrus d’Amorim Santa-Cruz, and José G. A. Pacheco
from room temperature up to 900 °C, at a heating rate of 5, 10, and 20 °C min −1 . The model-freekinetics proposed by Vyazovkin and co-workers [ 11 , 12 ] was used to evaluate the kinetic parameters of surfactants decomposition from the optimized
Authors:S. Arias, M. Prieto, B. Ramajo, A. Espina, and J. García
The evaporation of octanoic (caprylic) acid was investigated by means of thermogravimetric analysis (temperature range: 300–600 K)
under a nitrogen dynamic atmosphere (heating rates: 0.16, 0.31, 0.63, 1.25, 2.5, 5 and 10 K min−1). Kinetic plots for a zero-order process were constructed based on the Arrhenius equation. The activation energy for the
evaporation process was calculated via both the Arrhenius plot and Vyazovkin’s isoconversional model-free method.
Authors:F. M. Aquino, D. M. A. Melo, R. C. Santiago, M. A. F. Melo, A. E. Martinelli, J. C. O. Freitas, and L. C. B. Araújo
The objective of this study is to study the thermal degradation of the ligand groups with the metallic ions of the system using the Flynn and Wall and “Model-freekinetics” methods and evaluate the results in order to establish the activation energy as
Authors:A. Rotaru, Anca Moanţă, P. Rotaru, and E. Segal
Thermal analysis of 4-[(4-chlorobenzyl)oxy]-4′-chloro-azobenzene dye, exhibiting liquid crystalline properties, was performed
in dynamic air atmosphere. The compound behavior was investigated using TG, DTG, DTA and DSC techniques, under non-isothermal
linear regime. The evolved gases were analyzed by FTIR spectroscopy. Kinetic parameters of the first decomposition step were
obtained by means of multi-heating rates methods, such as isoconversioanl methods, IKP method and Perez-Maqueda et al. criterion.
A software package to determine the non-isothermal kinetic parameters of heterogeneous reactions has been developed. The dynamic
handle of conversion degree step and ranges, heating rates and kinetic models makes the evaluation of the activation parameters
much faster. The standard procedure: ‘model-free’ kineitc, IKP and Perez-Maqueda et al. methods, is applied for the determination of the kinetic triplet corresponding to thermal induced transformations. The software
is designed mainly for thermogravimetric, temperature programmed reduction and dilatometry data processing, but may also import
already transformed numeric data.
Authors:V. Logvinenko, V. Fedorov, Yu. Mironov, and V. Drebushchak
Dehydration processes of series of rhenium cluster compounds were studied (by thermogravimetry, differential scanning calorimetry,
dilatometry methods). Cluster anions of compounds are [Re6S8Br6]3−, [Re6S7Br7]3−, [Re6S8(OH)6]4−, [Re6Se8(OH)6]4−. TG- and DSC-data were used for kinetic studies, these data were processed using special computer program with ‘model-free’
approach. Quantitative data on thermodynamic and kinetic stability of compounds are obtained. The role of water molecules
in the cluster compounds stability is discussed.