Thermal kinetics and decomposition mechanism of methylphenylphosphinic acid and diphenylphosphinic acid

Abstract

Thermal degradation and degradation kinetics of methylphenylphosphinic acid(MPPA) and diphenylphosphinic acid(DPPA) were investigated via thermogravimetric analysis(TGA) technique under non-isothermal conditions. The activation energies of the decomposition process for the two compounds were calculated through the Friedman and Kissinger-Akahira-Sunose(KAS) methods. The thermal decomposition mechanism was investigated by the Criado method based on a set of TGA data obtained at different heating rates. It was shown that the activation energies calculated from the decomposition reaction by different methods were consistent with each other. The results show that the probable model for the degradation of MPPA and DPPA agreed with the two-dimensional(D2) and three-dimensional(D4) diffusion models, respectively. Moreover, the thermodynamic functions(ΔH≠, ΔS≠, ΔG≠) of the two decomposition reactions were also calculated.