Early chemistry in hot and dense nitromethane: molecular dynamics simulations

M Riad Manaa; Evan J Reed; Laurence E Fried; Giulia Galli; François Gygi

doi:10.1063/1.1724820

Early chemistry in hot and dense nitromethane: molecular dynamics simulations

J Chem Phys. 2004 Jun 1;120(21):10146-53. doi: 10.1063/1.1724820.

Authors

M Riad Manaa¹, Evan J Reed, Laurence E Fried, Giulia Galli, François Gygi

Affiliation

¹ University of California, Lawrence Livermore National Laboratory, Livermore, CA 94551, USA.

PMID: 15268037
DOI: 10.1063/1.1724820

Abstract

We report density functional molecular dynamic simulations to determine the early chemical events of hot (T=3000 K) and dense (rho=1.97 g/cm(3), V/V(0)=0.68) nitromethane (CH(3)NO(2)). The first step in the decomposition process is an intermolecular proton abstraction mechanism that leads to the formation of CH(3)NO(2)H(+) and the aci ion H(2)CNO(2) (-). This event is also confirmed to occur in a fast annealing simulation to a final temperature of 4000 K at rho=2.20 g/cm(3). An intramolecular hydrogen transfer that transforms nitromethane into the aci acid form, CH(2)NO(2)H, accompanies this event. To our knowledge, this is the first confirmation of chemical reactivity with bond selectivity for an energetic material near the Chapman-Jouget state of the fully reacted material. We also report the decomposition mechanism followed up to the formation of H(2)O as the first stable product. We note that similarities in the global features of reactants, intermediates, and products of the reacting fluid seem to indicate a threshold for similar chemistry in the range of high densities and temperatures reported herein.