Toward Advanced High-Performance Insensitive FOX-7-like Energetic Materials via Positional Isomerization

Abstract

For an energetic molecule with a definite elemental composition, the substituent type and position are the most important factors to influence its detonation performance and mechanical sensitivities. In this work, two pairs of FOX-7-like energetic isomers based on (2 and HTz-FOX; 5 and 6) were synthesized and characterized. Through positional isomerization, advanced high-performance insensitive explosives were obtained. Compounds 2 and 5 with an amino group adjacent to the electron-withdrawing side of the ethene bridge show both higher thermal stability and lower mechanical sensitivities (2: T d = 258 °C, impact sensitivity (IS) = 25 J, and friction sensitivity (FS) = 300 N; 5: T d = 264 °C, IS = 30 J, and FS = 320 N). In addition, 2 shows ultrahigh detonation performance (D v = 9224 m s–1 and P = 31.1 GPa). These promising physicochemical properties are comparable to those of HMX (D v = 9193 m s–1, P = 37.8 GPa, T d = 275 °C, IS = 7.4 J, and FS = 120 N), which suggests that 2 may be a promising energetic material in future applications.

Bicyclic High-Energy and Low-Sensitivity Regioisomeric Energetic Compounds Based on Polynitrobenzene and Pyrazoles

“…However, the product was detected by mass spectrometry recording the presence of molecular ion peaks of the target compound, but the compound was unstable in air and degraded to form other substances. The structures of 1, 2, and 3 were confirmed by 1 H and 13 C NMR and additionally confirmed by X-ray singlecrystal diffraction. Crystal Structure.…”

“…1 H NMR (DMSO-d 6 ): δ = 9.24 (s, 2H), 8.06 (s, 2H) 6.30 (s, 2H) ppm. 13 Synthesis of 4-Nitro-N 5 -(2,4,6-trinitrophenyl)-1H-pyrazole-3,5-diamine (2). As shown in Scheme 1, picryl chloride (247 mg, 1 mmol) was added to a DMF solution of 4-nitro-1H-pyrazole-3,5diamine (357 mg, 2.5 mmol) for several times, after which the reaction solution was heated to 110 °C, and the reaction was carried out at that temperature for 5 h. After the temperature of the reaction solution decreased to room temperature, it is poured into water.…”

“…Nevertheless, TATB also has a problem that the sensitivity is too low to be triggered. In addition, the energy performance of TATB is also poor. , Hence, the development of energetic compounds with suitable sensitivity, excellent energetic performance, and a simple synthesis route is the main research direction in the energetic material field. − …”

Thermal stability of azole-rich energetic compounds: their structure, density, enthalpy of formation and energetic properties

“…Moreover, increasing the number of –NO 2 groups leads to a higher density and better detonation performance ( D = 6506–8256 m s −1 ; P = 14.4–28.6 GPa) (Table 1). Tang et al 75 achieved advanced high-performance insensitive explosives ( 25 and 26 ; 27 and 28 ) via positional isomerization. Compounds 26 and 28 , with an amino group adjacent to the electron-withdrawing side of the ethene bridge, display higher thermal stability ( 26 : T d = 258 °C; 28 : T d = 264 °C) (Fig.…”

“…Fig.4(a-m) Effect of regional isomerization on thermal stability 75,78,79,[84][85][86][89][90][91][92]. …”