Multiply Nitrated High-Energy Dense Oxidizers Derived from the Simple Amino Acid Glycine

Synthesis, Characterization and Energetic Performance of Oxalyl Diazide, Carbamoyl Azide, and N,N'-Bis(azidocarbonyl)hydrazine

As pure compounds, small carbonyl azides enjoy a bad reputation, due to the high explosive sensitivity and instability they demonstrate. Consequently, most reported examples have only been poorly characterized. The compounds oxalyl diazide (1), carbamoyl azide (2), as well as N,N'-bis(azidocarbonyl)hydrazine (3) were obtained by performing a diazotation reaction on the corresponding hydrazo precursor. Carbamoyl azide (2) could also be obtained from oxalyl diazide via Curtius rearrangement to the reactive isocyanate, followed by reaction with water. Further, different trapping reactions of the isocyanate with hydroxyl (methanol, oxetan-3-ol) and amino (2-amino-5H-tetrazole) functions are described. All products were extensively analyzed using IR, EA, DTA and multinuclear NMR spectroscopy, and the crystal structures elucidated using single crystal X-ray diffraction. In addition, the sensitivities toward friction and impact were determined and the energetic performances of the carbonyl azides were calculated using the EXPLO5 code.

Nitrocarbamoyl Azide O2NN(H)C(O)N3: A Stable but Highly Energetic Member of the Carbonyl Azide Family

The diazotization of nitrosemicarbazide (1) resulted in the formation and isolation of nitrocarbamoyl azide (2), which was thoroughly characterized by spectroscopic and structural methods. This compound shows surprising stability but also high reactivity and sensitivity, with a melting point of 72 °C and a detonative decomposition point at 83 °C. In addition, five selected salts were synthesized by careful deprotonation. The decomposition mechanism of 2 in solution was investigated and could be clarified by performing experiments using methanol and hydrazine as trapping reagents. The energetic and physicochemical properties of all these compounds were investigated and classified.

Toward reliable characterization of energetic materials: interplay of theory and thermal analysis in the study of the thermal stability of tetranitroacetimidic acid (TNAA)

The thermal stability of energetic materials, being of the utmost importance for safety issues, is often considered in terms of kinetics, e.g., the Arrhenius parameters of the decomposition rate constant. The latter, in turn, are commonly determined using conventional thermoanalytical procedures with the use of simple Kissinger or Ozawa methods for kinetic data processing. However, thermal decomposition of energetic materials typically occurs via numerous exo- and endothermal processes including fast parallel reactions, phase transitions, autocatalysis, etc. This leads to numerous drawbacks of simple approaches. In this paper, we proposed a new methodology for characterization of the thermochemistry and thermal stability of melt-cast energetic materials, which is comprised of a complementary set of experimental and theoretical techniques in conjunction with a suitable kinetic model. With the aid of the proposed methodology, we studied in detail a novel green oxidizer, tetranitroacetimidic acid (TNAA). The experimental mass loss kinetics in the melt was perfectly fitted with a model comprised of zero-order reaction (sublimation or evaporation) and first-order thermal decomposition of TNAA with the effective Arrhenius parameters Ea = 41.0 ± 0.2 kcal mol-1 and log(A/s-1) = 20.2 ± 0.1. We rationalized the experimental findings on the basis of highly accurate CCSD(T)-F12 quantum chemical calculations. Computations predict that thermolysis of TNAA involves an intricate interplay of multiple decomposition channels of the three tautomers, which are equilibrated via either monomolecular reactions or concerted double hydrogen atom transfer in the H-bonded dimers; the calculated Arrhenius parameters of the effective rate constant coincide well with experiment. Most importantly, calculations provide detailed mechanistic evidence missing in the thermoanalytical experiment and explain formation of the experimentally observed primary products N2O and NO2. Along with the kinetics and mechanism of decomposition, the proposed approach yields accurate thermochemistry and phase change data of TNAA.

Insensitive ionic bio-energetic materials derived from amino acids

Energetic salts/ionic liquids have received increasing attention as fascinating energetic materials, and the use of renewable compounds is a promising approach to developing energetic materials. Until recently, biomolecules have been used as raw materials to develop neutral energetic compounds, whereas research focused on ionic energetic materials obtained from natural bio-renewable frameworks is scarce. This work systematically investigates ionic bio-energetic materials (IBEMs) derived from sustainable natural amino acids. In addition to combustibility, high density, good thermal stability, and one-step preparation, these IBEMs demonstrated apparent hypotoxicity and insensitivity. Moreover, a theoretical examination was performed to explore their appropriate properties. The intriguing results of this study indicates that IBEMs are potential bio-based energetic materials.

N-Nitrosarcosine: An Economic Precursor for the Synthesis of New Energetic Materials

New energetic compounds have been synthesized starting from the readily available N-(cyanomethyl)-N-methylamine. From this, N-nitrosarcosine was prepared in few steps, which serves as a starting material for the synthesis of oxygen-rich compounds. The compounds were thoroughly characterized including multinuclear NMR and vibrational spectroscopy and also molecular structures by single X-ray diffraction were obtained. Their energetic properties were determined including the sensitivities towards impact and friction, their heat of formations were calculated and the detonation and combustion parameters were predicted using EXPLO5 V6.02.

Convenient synthesis of energetic polynitro materials including (NO2)3CCH2CH2NH3-saltsviaMichael addition of trinitromethane

Acrylamide and nitroform are precursors for the formation of the 3,3,3-trinitropropylammonium cation, which was combined with several oxygen-containing anions in order to serve as potential HEDO salts.

Oxygen-rich anion based energetic salts with high detonation performances

Novel energetic salts based on 2,2,2-trinitroethyl nitrocarbamate anion were synthesized, which exhibited promising detonation performances (detonation pressure: 29.4 to 33.1 GPa; detonation velocity: 8213 to 8596 m s⁻¹).

Novel trinitroethanol derivatives: high energetic 2-(2,2,2-trinitroethoxy)-1,3,5-triazines

The multicomponent reaction of 2,4,6-trichloro-1,3,5-triazine with potassium trinitromethane and trinitroethanol was exploited for the first synthesis of the hetaryl trinitroethyl ethers.

Studies on the synthesis and properties of polynitro compounds based on esteryl backbones

Four polynitro esters were derived from 2,2,2-trinitroethanol with multi-nitrobenzoic acids by transesterification.