Pyrolysis behaviors of di-tert-butyl peroxide in gas and liquid phases: A ReaxFF molecular dynamics simulation

Di-tert-butyl peroxide (DTBP) is widely used for various purposes, including as an initiator, vulcanizator, and fuel additive, but is susceptible to triggering fires and explosions owing to its high thermal risk. Therefore, understanding its atomistic pyrolysis mechanisms is of great importance. In this work, the pyrolysis of DTBP is investigated using ReaxFF molecular dynamics simulations with a validated reactive force field. The effect of temperature on the pyrolysis of DTBP is first investigated, followed by the product and intermediate distributions. The results reveal that the system density is crucial in the pyrolysis behaviors of DTBP. The pyrolysis products of gaseous DTBP are found to be acetone, ethane, and methyl tert-butyl ether, while those of liquid DTBP include acetone, tert-butanol, methyl tert-butyl ether, methane, 2-methoxypropene, isobutene, and methyl ethyl ketone, which is in reasonable agreement with the results of previously reported experiments. The detailed reaction pathways are then analyzed. In the initial reactions, the tert-butoxy radical ((CH₃)₃CO⋅) is generated by the homolysis of the O–O bond in all cases. In comparison to the gaseous phase, where the majority of subsequent reactions involve the decomposition of (CH₃)₃CO⋅, the liquid phase exhibits additional H-abstraction reactions leading to the formation of tert-butanol. This can be attributed to a stronger interplay between the radicals in the liquid environment. The findings from this work are anticipated to contribute valuable data for enhancing the process safety of DTBP.