Kinetic compensation effect: discounting the distortion provoked by accidental experimental errors in the isokinetic temperature value

Isokinetic and Compensation Temperature in the Analysis of Thermal Dissociation of the Solid Phase under Dynamic Conditions

“…The starting point of the calculation is the integration constant Equation ( 13), which initiates the possibility of confronting Equation ( 25), since formally in both cases E = const. Considerations for simulated data show that the integration constant (C) in Equations ( 14), ( 16), (19), (20) divides the kinetic data into a range of very low reaction/process rates from those corresponding to the higher temperature range and heating rates dα dlnT > 1. The KCE phenomenon, conventionally written as Equation ( 1) for β = T iso is characterized by the fact that dln A dE = RT iso ) −1 = const , so there is no simple way to relate to Equation (25) due to the variability of the ratio q T 0 = var for E = const.…”

“…Equations ( 2) and ( 4) contain thermodynamic activation functions derived from Eyring's theory from 1935 [12]. The theory has been adapted for modeling complex reaction/process pathways, as well as for the practical use of selected relationships captured by Equations ( 2)- (5) [1,3,5,8,9,[13][14][15][16][17][18][19][20]. Some of the mentioned works combine Eyring's theory with the Arrhenius equation [13,14,18].…”

“…Analyzing the experimental data obtained under isothermal and dynamic conditions, a large discrepancy in the values of determined isokinetic temperatures can be observed. The application of isothermal, dynamic or isoconversional kinetic functions for modeling does not lead to one common isokinetic temperature value [20]. Thus, it can be expected that the reliability of Equation (2) or Equation ( 4) is dependent on the parameters determined from kinetic equations or reduced to thermokinetics, consistent with the classical Arrhenius equation, i.e., ln A vs. E. Consequently, the possibility of confronting the isoconversion and compensation temperature relationships arises.…”

“…Knowing the intercept in the relationship ln[g(α)] vs. 1/T, the initial conversion degree can be determined from Equation (24). In Equation (20), the inversion of the coordinate system for T = T 0 and after double-sided logarithmizing leads to:…”

“…while the second one uses the Doyle approximation for the intercept presented in [20]: Equations ( 35) and ( 36) can be applied to isoconversional analyses in the form:…”