Decomposition of condensed phase energetic materials: Interplay between uni- and bimolecular mechanisms

David Furman, Ronnie Kosloff, Faina Dubnikova, Sergey V. Zybin, William A. Goddard, Naomi Rom, Barak Hirshberg, Yehuda Zeiri

Research output: Contribution to journalArticlepeer-review

113 Scopus citations

Abstract

Activation energy for the decomposition of explosives is a crucial parameter of performance. The dramatic suppression of activation energy in condensed phase decomposition of nitroaromatic explosives has been an unresolved issue for over a decade. We rationalize the reduction in activation energy as a result of a mechanistic change from unimolecular decomposition in the gas phase to a series of radical bimolecular reactions in the condensed phase. This is in contrast to other classes of explosives, such as nitramines and nitrate esters, whose decomposition proceeds via unimolecular reactions both in the gas and in the condensed phase. The thermal decomposition of a model nitroaromatic explosive, 2,4,6-trinitrotoluene (TNT), is presented as a prime example. Electronic structure and reactive molecular dynamics (ReaxFF-lg) calculations enable to directly probe the condensed phase chemistry under extreme conditions of temperature and pressure, identifying the key bimolecular radical reactions responsible for the low activation route. This study elucidates the origin of the difference between the activation energies in the gas phase (∼62 kcal/mol) and the condensed phase (∼35 kcal/mol) of TNT and identifies the corresponding universal principle. On the basis of these findings, the different reactivities of nitro-based organic explosives are rationalized as an interplay between uni- and bimolecular processes.

Original languageEnglish
Pages (from-to)4192-4200
Number of pages9
JournalJournal of the American Chemical Society
Volume136
Issue number11
DOIs
StatePublished - 19 Mar 2014

ASJC Scopus subject areas

  • Catalysis
  • Chemistry (all)
  • Biochemistry
  • Colloid and Surface Chemistry

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