Atomistic-Scale Simulations of the Initial Chemical Events in the Thermal Initiation of Triacetonetriperoxide

• Published in: Journal of the American Chemical Society 2005-08, Vol.127 (31), p.11053-11062
• Main Authors: van Duin, Adri C. T, Zeiri, Yehuda, Dubnikova, Faina, Kosloff, Ronnie, Goddard, William A
• Format: Article
• Language: English
• Subjects: Applied sciences; Chemical industry and chemicals; Chemistry; Exact sciences and technology; Industrial chemicals; Kinetics and mechanisms; Organic chemistry; Powders, propellants, explosives; Reactivity and mechanisms
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja052067y

To study the initial chemical events related to the detonation of triacetonetriperoxide (TATP), we have performed a series of molecular dynamics (MD) simulations. In these simulations we used the ReaxFF reactive force field, which we have extended to reproduce the quantum mechanics (QM)-derived relative energies of the reactants, products, intermediates, and transition states related to the TATP unimolecular decomposition. We find excellent agreement between the QM-predicted reaction products and those observed from 100 independent ReaxFF unimolecular MD cookoff simulations. Furthermore, the primary reaction products and average initiation temperature observed in these 100 independent unimolecular cookoff simulations match closely with those observed from a TATP condensed-phase cookoff simulation, indicating that unimolecular decomposition dominates the thermal initiation of the TATP condensed phase. Our simulations demonstrate that thermal initiation of condensed-phase TATP is entropy-driven (rather than enthalpy-driven), since the initial reaction (which mainly leads to the formation of acetone, O2, and several unstable C3H6O2 isomers) is almost energy-neutral. The O2 generated in the initiation steps is subsequently utilized in exothermic secondary reactions, leading finally to formation of water and a wide range of small hydrocarbons, acids, aldehydes, ketones, ethers, and alcohols.