Atomistic insights into the pyrolysis of methyl ethyl ketone peroxide via ReaxFF molecular dynamics simulation

Methyl ethyl ketone peroxide (MEKP) has caused the largest number of incidents among organic peroxides due to the thermal risk. However, the mechanisms of pyrolysis reactions are still unclear. Herein, the pyrolysis of the MEKP dimer and monomer, the predominant existence forms of commercial MEKP, is investigated via the ReaxFF molecular dynamics simulations. The results show that there exist two-stage reactions, consistent with the reported experiments. In the primary reaction, large numbers of butanone, O₂, and water are generated. The consumption of O₂ will trigger the secondary exothermic reaction, leading to the generation of many small molecules such as H₂O, CH₂[dbnd]CH₂, CH₂[dbnd]C[dbnd]O, CO₂, and CO. The products of the MEKP dimer and monomer are the same. To clarify the detailed mechanisms of pyrolysis, we investigate the pathways of initial reactions, most of which are associated with the O–O bond scission. The initial reactions are composed of the splitting decomposition and self-reactions with the MEKP itself or the radicals. In addition, the main generation and consumption pathways of the major species are tracked, including butanone, O₂, and water. Finally, the apparent activation energies calculated by ReaxFF simulations are consistent with the experimental results. These findings are expected to provide fundamental guidance for the process safety in the production, transportation, and storage of organic peroxides.