Nitramide

Abstract: This qualitative study examines the response of the novel energetic material ammonium dinitramide (ADN), NH4N(NO2)2, to thermal stress under low heating rate conditions in a new experimental apparatus. It involved a combination of residual gas mass spectrometry and FTIR absorption spectroscopy of a thin cryogenic condensate film resulting from deposition of ADN pyrolysis products on a KCl window. The results of ADN pyrolysis were compared under similar conditions with the behavior of NH4NO3 and NH2NO2 (nitramide), which served as reference materials. NH4NO3 decomposes into HNO3 and NH3 at 182°C and is regenerated on the cold cryostat surface. HNO3 undergoes presumably heterogeneous loss to a minor extent such that the condensed film of NH4NO3 contains occluded NH3. Nitramide undergoes efficient heterogeneous decomposition to N2O and H2O even at ambient temperature so that pyrolysis experiments at higher temperatures were not possible. However, the presence of nitramide can be monitored by mass spectrometry at its molecular ion (m/ℯ 62). ADN pyrolysis is dominated by decomposition into NH3 and HN(NO2)2 (HDN) in analogy to NH4NO3, with a maximum rate of decomposition under our conditions at approximately 155°C. The two vapor phase components regenerate ADN on the cold cryostat surface in addition to deposition of the pure acid HDN and H2O. Condensed phase HDN is found to be stable for indefinite periods of time at ambient temperature and vacuum conditions, whereas fast heterogeneous decomposition of HDN at higher temperature leads to N2O and HNO3. The HNO3 then undergoes fast (heterogeneous) decomposition in some experiments. Gas phase HDN also undergoes fast heterogeneous decomposition to NO and other products, probably on the internal surface (ca. 60°C) of the vacuum chamber before mass spectrometric detection. © 1993 John Wiley & Sons, Inc.

Abstract: ROBERTA P. SAXON and MEGUMU YOSHIMINE. Can. J . Chem. 70, 572 (1992). Calculations designed to characterize the transition state and determine the barrier height for rearrangement of nitromethane to methyl nitrite are reported. Structures of CH,NO,, C H 3 0 N 0 , dissociation products, CH3 + NOz and CH,O + NO, and the transition state for nitro-nitrite rearrangement have been optimized at the MCSCF/4-31G level. The geometry of the transition state may be approximately described as separated CH3 and NO, species with extremely long C-N and C 4 bond lengths, 3.396 and 3.654 A, respectively. Energies have been obtained by large-scale multireference singleand double-excitation CI calculations (6-3 lG:+ basis). The transition state is calculated to lie 56.7 kcal/mol above nitromethane (with zero-point energy). A C-N bond dissociation energy of 51.7 kcal/mol is obtained. Results are compared with the infrared multiphoton dissociation experiment of Wodtke, Hintsa, and Lee.

Abstract: A kinetic study of the thermal decomposition of NH4NO3 in the presence of NaCl has been carried out using the differential kinetic technique previously described. The rate law for N2 evolution is of the form k1(NH4+)+k2(NH4+) (Cl—)½. A radical mechanism is proposed in which the role of chloride is catalytic, being oxidized by NO2+ to Cl atoms which are reduced back by NH4+ and NH3. These hydrogen abstraction reactions leave NH3+ and NH2, respectively, in reaction cages in which subsequent radical recombinations yield nitramide and nitrosamine as precursors for N2O and N2. Parallel Cl atom recombinations give Cl2, part of which escapes by volatilization, the rest reacting with NH3 to provide a second source of N2.

Abstract: s In this study, a series of energetic compounds based on C–C linked 1,2,3-triazole and 1,2,4-triazole were synthesized and characterized, i.e., 5-(5-nitro-2H-1,2,3-triazole-4-yl)-4H-1,2,4-triazole-3,4-diamine (compound 1), N-(3-amino-5-(5-nitro-2H-1,2,3-triazole-4-yl)-4H-1,2,4-triazole-4-yl) nitramide (compound 4), and their energetic salts (compounds 2, 3, 5, and 6). The structures of compounds 1, 2, and 4 were determined by X-ray diffraction. All the new compounds feature acceptable thermal stability (Tdec ​= ​185–266 ​°C), with thermal decomposition temperature higher than that of RDX (Tdec ​= ​204 ​°C) except for compound 6 (Tdec ​= ​185 ​°C). Moreover, the detonation velocities of compounds 5 and 6 are 9200 ​m·s−1 and 9024 ​m·s−1, respectively, which are higher than that of RDX (D ​= ​8795 ​m·s−1). Furthermore, the new compounds show low mechanical sensitivity (IS ​= ​20 ​J, FS ​= ​240 ​N) compared to RDX (IS ​= ​7.4 ​J, FS ​= ​120 ​N). These results will help to accelerate the development of new high-energy density materials.