Combustion of 1,5-Dinitrobiuret (DNB) in the Presence of Nitric Acid Using ReaxFF Molecular Dynamics Simulations

In
this study we have examined the combustion dynamics of 1,5-dinitrobiuret
(DNB) and nitric acid using reactive molecular dynamics simulations.
Simulations were performed using the ReaxFF force field with parameters
that were fitted against quantum mechanical calculations on model
compounds/clusters relevant for this particular chemical system. Several
different compositions were investigated, at densities of 0.5 and
1.0 g/mL, to examine the reaction kinetics in a dense vapor and liquid
phase of these mixtures. Our simulations show that at certain compositions
of the mixture reaction kinetics result in a very sharp release of
thermal energy, which we associate with spontaneous ignition or hypergolicity.
Analysis of key reaction mechanisms responsible for this process is
discussed.