Decomposition of Diisopropyl Methylphosphonate and Fluorine-Substituted Isomers on Mixed Metal-Oxide Surfaces: Mechanisms from Ab Initio Molecular Dynamics

Mixed metal-oxide surfaces have attracted significant interest in their ability to efficiently neutralize organophosphorus-based chemical warfare agents (CWAs). However, these processes occur under complex reactive conditions at high temperatures, and the detailed mechanisms of the neutralization process are not well-understood. To shed mechanistic insight into the neutralization process, we have carried out extensive quantum calculations to investigate the high-temperature degradation of diisopropyl methylphosphonate (DIMP), a simulant for chemical warfare agents, as well as its fluorine-substituted isomer. Our Born–Oppenheimer molecular dynamics (BOMD) simulations reveal that the CuAl2O4 (110) surface rapidly adsorbs DIMP/fluorine-substituted DIMP, resulting in subsequent decomposition via C–O bond cleavage and propene elimination. Our quantum calculations provide detailed insight into the atomistic decomposition mechanisms of DIMP/fluorine-substituted DIMP to guide future efforts to neutralize these hazardous compounds.