Determination of the Kinetic Parameters of Multistage Condensed Phase Reactions

Abstract

The discrete cosine transform (DCT) and Chebyshev series expansion (CSE) have the capability of approximating the functions with zero error at specific points known as nodes. Based on this property, this study introduces an isoconversional analysis method for complex reactions using the DCT or CSE models for the conversion function, applicable to both isothermal and nonisothermal conditions. The new method was applied to the kinetic data from simulated reactions as well as the thermal degradation of the polymer coating of an optical fiber. The results demonstrate that the DCT and CSE facilitate the calculation of kinetic parameters with very high accuracy. Notably, the conversion function and pre-exponential factor of complex multistage reactions, with multiple peaks in reaction rate curves, can be accurately estimated using the new approach. The GNU Octave/MATLAB codes have been made available to readers, enabling them to apply the novel method to their own kinetic data.