Investigation of pyrolysis kinetics, mechanism and thermal stability of tert-butyl peroxy-2-ethyl hexanoate

Tert-butyl peroxy-2-ethyl hexanoate (TBPO), an important organic peroxide, is widely used as a polymerization initiator and curing agent in the chemical industry. Its thermal instability due to the presence of the peroxide bond may incur a decomposition reaction and cause further thermal runaway. The pyrolysis characteristics of TBPO were assessed by three advanced calorimetry techniques. The apparent activation energies under dynamic and adiabatic conditions were calculated, and critical thermal safety parameters were determined. The specific distribution of the pyrolysis products of TBPO were identified by combining thermogravimetry-Fourier transform infrared spectroscopy (TG-FTIR) and gas chromatography/mass spectrometry (GC/MS), and the most likely pyrolysis mechanism was proposed. In addition, density functional theory (DFT) was used to evaluate the activation free energy and activation free enthalpy for each step of the pyrolysis process at the B3LYP/def2-TZVP calculation level, and kinetic calculations at different temperatures were performed by using the conventional transition state theory. The theoretical simulation results were found to be in good agreement with the experimental data. The findings of this study can provide a favorable reference to forestall thermal safety accidents in the actual storage, transportation, and operation of TBPO.