Thermal hazards and initial decomposition mechanisms study of four tert-butyl organic peroxides combining experiments with density functional theory method

Abstract

Thermal hazards and initial decomposition mechanisms of di-tert-butyl peroxide (DTBP), tert-butyl cumyl peroxide (TBCP), tert-butyl peroxy benzoate (TBPB) and tert-butyl peroxy-2-ethylhexanoate (TBPEH) were comprehensively studied. Activation energies of the four tert-butyl organic peroxides (TBOPs) were obtained by differential scanning calorimetry (DSC) experiments and kinetic analysis methods. Adiabatic thermal decomposition characteristic parameters were obtained by accelerating rate calorimeter (ARC) and thermal risk was evaluated by matrix assessment. Thermal decomposition products were determined by gas chromatography-mass spectrometry (GC-MS) experiments and decomposition pathways were proposed according to the analytical results. The energy of each step of the proposed pathways was calculated by density functional theory (DFT) method. The results indicated that all of the four TBOPs were divided into class Ⅲ unacceptable hazard. Acetone was the main decomposition product of the four TBOPs. The most likely decomposition step to generate acetone was that the tert-butane oxygen radical detached a methyl. The main pathway was determined by comparing the energy barrier of rate-determining step. This work provided helpful suggestions for the safe application of the four TBOPs in the practical chemical process.