posted on 2021-09-29, 19:40authored byTeng Zhang, Xiang Li, Chong Zhang, Lang Chen, Bingcheng Hu, Jun Chen
Detonation
energy of novel cyclo-N5–-based nitrogen-rich
energetic salts is expected to exceed 3 times
the equivalent of TNT. PHAC([(N5)6(H3O)3(NH4)4Cl]) was selected as the
prototype to investigate the thermal decomposition reaction of PHAC
in the solid phase for the first time by the first-principles molecular
dynamics method. At about 38 ps, the final state of the reaction was
reached. It was found that there were mainly five final products,
among which the proportion of N2 molecules was the maximum
and accounted for 60% (mole fraction) of all final products. The reaction
pathways of PHAC were analyzed, and more than 30 elementary reactions
were found. The initial reaction of the PHAC thermal decomposition
was the ring-opening of cyclo-N5– ion
and proton transfer. The energy release of PHAC thermal decomposition
is divided into two stages. The first stage is a slow release of energy
before the formation of the HN3 molecule. The second stage
is the rapid release of energy after the formation of HN3 molecules. The HN3 molecule is an essential junction,
and the unimolecular dissociation of HN3 is the rate-determining
step. Such an understanding of reaction mechanism and energy release
law greatly promotes the application and synthesis of novel cyclo-N5–-based nitrogen-rich energetic salts.