High-Temperature Decomposition of Diisopropyl Methylphosphonate (DIMP) on Alumina: Mechanistic Predictions from Ab Initio Molecular Dynamics
| Autor: | Biswas, Sohag, Wong, Bryan M. |
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| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | Journal of Physical Chemistry C, 125, 21922-21932 (2021) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1021/acs.jpcc.1c05632 |
| Popis: | The enhanced degradation of organophosphorous-based chemical warfare agents (CWAs) on metal-oxide surfaces holds immense promise for neutralization efforts; however, the underlying mechanisms in this process remain poorly understood. We utilize large-scale quantum calculations for the first time to probe the high-temperature degradation of diisopropyl methylphosphonate (DIMP), a nerve agent simulant. Our Born-Oppenheimer molecular dynamics (BOMD) calculations show that the $\gamma$-Al$_2$O$_3$ surface shows immense promise for quickly adsorbing and destroying CWAs. We find that the alumina surface quickly adsorbs DIMP at all temperatures, and subsequent decomposition of DIMP proceeds via a propene elimination. Our BOMD calculations are complemented with metadynamics simulations to produce free energy paths, which show that the activation barrier decreases with temperature and DIMP readily decomposes on $\gamma$-Al$_2$O$_3$. Our first-principle BOMD and metadynamics simulations provide crucial diagnostics for sarin decomposition models and mechanistic information for examining CWA decomposition reactions on other candidate metal oxide surfaces. Comment: Accepted by the Journal of Physical Chemistry C |
| Databáze: | arXiv |
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