Microscopic pyrolysis mechanism of tert-butyl hydroperoxide via ReaxFF molecular dynamics

Tert-butyl hydroperoxide (TBHP) is a common curing agent and free radical initiator in petrochemical industries, but may trigger fires and explosions once it decomposes. Therefore, it is imperative to elucidate the pyrolysis mechanism. Herein, the pyrolysis behaviors of TBHP are investigated via ReaxFF molecular dynamics simulations with a reliable force field validated by the density functional theory (DFT) method. The main pyrolysis products of water, acetone, methanol, oxygen, isobutene, methane, tert-butyl alcohol, formaldehyde, and propene, are all detected in the reported experiments. It is found that the peroxy bond scission and the hydrogen abstraction of TBHP by the radicals are two main initial reactions. In the subsequent reactions, the decomposition pathways of two main large radicals of (CH₃)₃CO· and (CH₃)₃COO· are tracked, followed by the main consumption and generation channels of the small reactive species of ·OH, ·CH₃, and O₂. A detailed reaction scheme of the TBHP pyrolysis is thus proposed. In addition, the apparent activation energy is calculated as 20.8 kcal/mol, which reasonably agrees with the experimental value. This work will provide scientific guidance for the process safety of organic peroxides and the development of suppression technologies.