Cyclic Dinitroureas As Self-Remediating Munition Charges

Abstract
As a potential solution to persistent environmental problems posed by conventional nitramines in unexploded ordnance (UXO), we investigated certain cyclic N,N'-dinitrourea derivatives: tetranitroglycoluril (TNGU) and hexanitrohexaazatricyclododecanedione (HHTDD), comparable in performance to HMX and CL-20. A property these compounds have in common that has kept them from widespread adoption by most weapons systems is a property that makes them attractive in specific systems that are susceptible to causing environmental problems as UXO: they are more hydrolytically reactive than simple alicyclic nitramines such as RDX. We quantified these ingredients' susceptibility to environmental hydrolysis in order to demonstrate that they show acceptable stability for processing into munitions but also suitable reactivity with environmental elements that they would undergo sufficiently rapid spontaneous (environmentally adventitious) degradation as to constitute self-remediation. The kinetics of ingredient degradation were determined under several environmental conditions. TNGU and HHTDD were seen to be stable enough in humidity-controlled air to manufacture and process; in moist soil and even in humid air, however, they degrade over hours to a very few days, and kinetic analysis shows the hydrolysis to be autocatalytic in mechanism. It is concluded that this class of ingredients does offer suitable replacements for conventional nitramines in venues that are susceptible to UXO formation.