Enhancement of Energetic Performance through the Construction of Trinitromethyl Substituted β-Bis(1,2,4-oxadiazole)

Halogen-free substitutions of ammonium perchlorate (AP), which meet the requirements of high density, high performance, and acceptable stability, have been a subject of scientific research for many years. In this work, by regrouping atoms in trinitromethyl substituted bis(1,2,4-oxadiazole), a novel oxidizer, trinitromethyl substituted β-bis(1,2,4-oxadiazole) (3), was designed and synthesized. It possesses an improved density (ρ = 2.002 g cm^-3 at 170 K, ρ = 1.942 g cm^-3 at 298 K) and thermal stability (T_d = 142.8 °C) in comparison to its regioisomer 5,5'-bis(trinitromethyl)-3,3'-bi(1,2,4-oxadiazole) (E). The properties for 3 were studied by both experimental and theoretical methods. The high positive oxygen balance of +7.3% and high specific impulse of 250 s also make compound 3 a promising candidate for an energetic oxidizer.

Laser ignition of energetic complexes: impact of metal ion on laser initiation ability

Alkali metal-containing energetic complexes were easy to initiate, followed by the free ligand, whereas the alkaline-earth metal complexes exhibited longer initiation delay times.

Synthesis, crystal structure, and thermal properties of Ni(NH3)4(AFT)2

Ni(NH3)4(AFT)2 [NiC6H16N18O2, AFT = 4-amino-3-(5-tetrazolate)furazan] is synthesized and characterized by elemental analysis and Fourier-transform infrared spectroscopy for the first time. X-ray diffraction measurements are used to determine the crystal structure of compound 1. The results demonstrate that compound 1 crystallized in the orthorhombic crystal system. The nickel(II) ion is six-coordinated by N atoms from two AFT-ligands and four NH3 molecules. Its thermal properties are investigated by differential scanning calorimetry and thermogravimetry-derivative thermogravimetry methods, with the results demonstrating that the differential scanning calorimetry curve exhibits two endothermic and one exothermic processes. The endothermic processes are in the range of 130–510 °C with a peak temperature of 188 °C. The temperature from 230 to 400 °C is the exothermic process in which the peak temperature is 314.58 °C. In addition, Kissinger’s and Ozawa-Doyle’s methods are used for calculating the non-isothermal kinetics parameters. Moreover, the apparent activation energy ( E), safety, and thermal stability parameters ( TSADT, TTIT, Tb) for Ni(NH3)4(AFT)2 are calculated. In addition, the calculated thermodynamic functions ( ∆S≠, ∆H≠, and ∆G≠) for the exothermic decomposition process of Ni(NH3)4(AFT)2 are 55.07 J mol−1 K−1, 196.18 kJ mol−1, and 164.90 kJ mol−1, respectively.

Derivatives of 3,6-Bis(3-aminofurazan-4-ylamino)-1,2,4,5-tetrazine: Excellent Energetic Properties with Lower Sensitivities

To find a balance between energy and safety, a series of compounds based on azo-, azoxy-, 1,4,2,5-dioxadiazene-, and 3,6-diamino-1,2,4,5-tetrazine-bridged bis(aminofurazan) were designed and synthesized. These compounds were analyzed by nitro group charges (Q_nitro) and bond dissociation energy (BDE) calculations, which are related to sensitivity and stability. Based on the calculated results, derivatives of 3,6-bis(3-aminofurazan-4-ylamino)-1,2,4,5-tetrazine have the largest values for -Q_nitro and BDE of all of the bis(aminofurazan) compounds. This shows that compounds based on 3,6-bis(3-aminofurazan-4-ylamino)-1,2,4,5-tetrazine have the lowest sensitivities and best stabilities, which has been substantiated by experiments. Additionally, their explosive properties remain essentially competitive with compounds based on azo-, azoxy-, and 1,4,2,5-dioxadiazene-bridged bis(aminofurazan). Hirshfeld surface calculations were also performed to better understand the relationship between the molecular structure and stability/sensitivity. This work highlights the value of 3,6-diamino-1,2,4,5-tetrazine as a linker to achieve good balance between safety and energy.

3-Trinitromethyl-4-nitro-5-nitramine-1H-pyrazole: a high energy density oxidizer

A novel oxygen-rich compound was designed and synthesized. The combination of high density, positive heat of formation, high positive oxygen balance, high specific impulse and high detonation performance makes it a promising high energy density oxidizer.

N,N′-Methylenebis(N-(1,2,5-oxadiazol-3-yl)nitramide) derivatives as metal-free green primary explosives

Metal-free green primary explosives with excellent detonation properties and acceptable sensitivities were synthesized and fully characterized.

5-Amino-1H-1,2,4-triazole-3-carbohydrazide and its applications in the synthesis of energetic salts: a new strategy for constructing the nitrogen-rich cation based on the energetic moiety combination

A new strategy for constructing a nitrogen-rich cation through energetic moiety (energetic “gene”) combination was presented and its derivatives were synthesized.