Diazeniumdiolate Energetic Materials
presentationposted on 06.05.2016, 00:00 authored by Molly Plemel
Polynitrogen anions and cations such as N3- and N5+ are well known high energy density materials (HEDM). The exclusively nitrogeneous materials draw their high energy from the vast differences in the nitrogen-nitrogen triple, double, and single bonds (226.9, 100.9, and 38.4 kcal/mol, respectively) and are friction or impact sensitive and explosive. However, nitrogen-rich compounds, which also contain C, H, and N atoms, are not as explosive and the heteroatoms allow for the "dilution" of the fragile N-N bonds and for the fine-tuning of high energy density properties of the compounds. We have synthesized a series of light-weight nitrogen-rich diazeniumdiolate HEDM's from N-alkylhydroxylamine and nitroalkane starting materials. N-Methyl- and N-ethylhydroxylamines react with nitrous acid to form the non-explosive HEDM acids CH3N2O2H and C2H5N2O2H, which are readily converted to their alkali metal (Li, Na, and K) salts. The alkylhydroxylamines also react with NO gas and alkali hydroxides under anaerobic conditions at -10 °C to form methane- or ethane-α-oximinodiazeniumdiolate salts. The latter series of compounds are isolated as the ammonium, lithium, sodium, and potassium salts and can also be synthesized from nitromethane and nitroethane. The new diazeniumdiolates decompose exothermically with ΔH > 1000 J/g and qualify as HEDM's. The new HEDM's are characterized by 1H NMR, UV-Vis, and IR spectroscopic data.