RESUMEN
Nitrogen-rich energetic materials have been the focus of a few studies on their isomers. Novel nitrogen-rich energetic compounds TZ, DTZ, and NTZ were synthesized through simple steps. The hydrogen bond networks significantly enhanced their properties (TZ, Td = 290 °C and Dv = 8370 m s-1; DTZ, Td = 282 °C and Dv = 8392 m s-1; and NTZ, Td = 272 °C and Dv = 8762 m s-1), which are superior to their isomers. This realized a balance between the energy and stability of polycyclic tetrazoles, providing insights for high-performance energetic materials.
RESUMEN
Nowadays, thousands of energetic materials have been synthesized, but only a few compounds meet all the high standards of detonation performance comparable to that of the widely used military explosive RDX, thermal stability comparable to that of the most widely used heat-resistant explosive HNS, and impact sensitivity comparable to that of the traditional explosive TNT. Also, as a goal, a novel and unexpected one-step method for constructing the furoxan-bridged energetic compound 3,4-bis(3,8-dinitropyrazolo[5,1-c][1,2,4]triazin-4-amino-7-yl)-1,2,5-oxadiazole 2-oxide (OTF) has been achieved under the conventional TFA/100% HNO3 nitration reaction system from the acetic acid intermediate. In this work, OTF with a high density of 1.90 g cm-3, the highest decomposition temperature of 310 °C (onset) among furoxan-based high explosives to date, superior detonation velocity (DV: 9109 m s-1), and low sensitivity (IS: 25 J) is reported. This work is a giant step forward in the development of advanced high-energy heat-resistant explosives and could improve future possibilities for the design of furoxan-based energetic materials.
RESUMEN
In recent years, with the development of deep coal mines and petroleum resources and the expansion of the aerospace industry, the pursuit of heat-resistant energetic materials with high thermal stability and high energy has been increasing. Bis(4-nitropyrazole) was employed as an energy bridge to link 1,2,4-triazole, thereby constructing a sophisticated tetracyclic framework in this study. A tetracyclic heat-resistant explosive 5,5'-(4,4'-dinitro-2H,2'H-[3,3'-bipyrazole]-5,5'-diyl)bis(4H-1,2,4-triazole-3,4-diamine) (3) and its derivatives 6-8 with excellent comprehensive performance have been successfully prepared. Particularly noteworthy is that compound 3 has a detonation velocity of 8604 m s-1, which exceeds that of the conventional heat-resistant explosive HNS with a velocity of 7164 m s-1. Furthermore, compound 3 has higher thermal stability (Td = 340 °C) than HNS (Td = 318 °C). In addition, the tetracyclic compound 3 also exhibited extraordinarily low sensitivity (IS > 40 J; FS > 360 N). These unique characteristics make it a potential candidate for novel heat-resistant and insensitive energetic materials.
RESUMEN
This work presents the successful synthesis of a series of fused energetic compounds using the strategy of structural modification from local carbonyl to hydroxylamine, hydrazone or methylamine. Hydroxylamine-substituted compound 2 exhibits high density, high detonation performance and low sensitivities as a secondary explosive.
RESUMEN
A route for fused [5,5,5,6]-tetracyclic energetic compounds based on the facile cyclization reaction has been explored. Fused [5,5,5,6]-tetracyclic compound 4 shows a high measured density (1.924 g cm-3), a low sensitivity (IS = 10 J, and FS = 144 N), and an excellent detonation velocity (9241 m s-1), which are much better than those of RDX. The results indicate that compound 4 is a potential candidate as a secondary explosive and provide new insight into the construction of fused polycyclic heterocycles.
RESUMEN
This study explores a straightforward synthetic strategy for preparing fused [5,6,5,5]-tetracyclic energetic compounds. Compound 4 has a high thermostability (Td = 307 °C), which is comparable to that of traditional heat-resistant explosive HNS (Td = 318 °C), but a higher detonation velocity (8262 m s-1) than HNS (7612 m s-1). These results indicate that compound 4 deserves further investigation as a potential heat-resistant explosive.
RESUMEN
It is still an urgent problem in the field of energetic materials to explore the synthesis of heat-resistant compounds with balanced energy and thermal stability through simple synthetic routes. Recently, fused compounds are considered to provide a promising framework for the construction of ideal heat-resistant compounds. In this study, three novel C-C bonded bis-5,6 fused triazole-triazine compounds, 3,3'-dinitro-[7,7'-bi[1,2,4]triazolo[5,1-c][1,2,4]triazine]-4,4'-diamine (2), 4,4'-diamino-[7,7'-bi[1,2,4]triazolo[5,1-c][1,2,4]triazine]-3,3'-dicarbonitrile (3), and 3,3'-di(1H-tetrazol-5-yl)-[7,7'-bi[1,2,4]triazolo[5,1-c][1,2,4]triazine]-4,4'-diamine (4), were synthesized by a simple method. Compound 2 exhibited an approaching detonation velocity of 8837 m s-1 compared with that of the traditional high energy explosive RDX velocity of 8795 m s-1, while its thermal stability (Td = 327 °C) was comparable to that of the heat-resistant explosive HNS (Td = 318 °C). At the same time, the double fused compound 2 also realized high density (1.90 g cm-3) and extremely low sensitivity (FS > 360 N, IS > 40 J). The above good comprehensive properties prove that compound 2 can be used as a potential insensitive high-energy heat-resistant explosive. In addition, the effects of the crystal structure on the sensitivity and thermal stability were studied using the quantum chemical methods. These results imply that the formation of double fused ring compounds by the ring closing reaction at symmetrical positions is an ideal strategy for the development of advanced heat-resistant explosives.
RESUMEN
The introduction of azido groups into the energetic skeleton has the advantages of increasing the energy level. In this work, a series of azido compounds with good stability and low sensitivity as well as tetrazole-fused compounds based on energetic salts are synthesized. The detonation pressures and velocities of these new compounds fall in the ranges of 18.9-27.3 GPa and 7153-8450 m s-1, respectively. The detonation velocity of the tetrazole-fused compounds based on the potassium salts 3, 6, and 7 are 7810, 7153, and 7989 m s-1, respectively. Also, their decomposition temperatures (244, 237, and 240 °C, respectively) are higher than that of traditional explosive RDX (204 °C). Notably, two representative compounds 2 and 5 possess higher decomposition temperature (2: 196 °C and 5: 178 °C) and overall detonation properties (2: D = 8129 m s-1 and P = 26.6 GPa and 5: D = 8336 m s-1 and P = 27.3 GPa) as well as relativity lower sensitivities (2: IS = 12 J and FS = 240 N and 5: IS = 10 J and FS = 144 N) than that of primary explosive 2-diazo-4,6-dinitrophenol (Td = 157 °C, D = 6900 m s-1, P = 24.7 GPa, IS = 1 J, and FS = 24.7 N). Moreover, the initiation capacity of compounds 2 and 5 was also assessed through the initiation tests. The results indicate that the two compounds could be a promising environmentally friendly primary explosive.
RESUMEN
Two series of both nitrogen-rich and thermostable energetic materials as well as their energetic salts based on hetarenecarboxylic acids are now described. Among these new compounds, neutral compounds 3 and 10 have higher nitrogen contents (69.66% and 63.05%) than their energetic salts, which suggests that they could be used as green energetic materials. In addition, compound 3 shows a good decomposition temperature (Td = 281 °C), which is close to that of TNT (Td = 295 °C). Nitrogen-rich salt 6 exhibits better integrated energetic-properties (D = 8913 m s-1, IS = 24 J, FS = 320 N) than RDX (D = 8795 m s-1, IS = 7.5 J, FS = 120 N).
RESUMEN
In this work, a series of pyrazole-derived energetic compounds were successfully synthesized. These energetic compounds were fully characterized by NMR spectroscopy, IR spectroscopy, and elemental analysis. The structures of compounds 5, 6, 7 and 7a were determined by single crystal X-ray diffraction. The physicochemical and energetic properties of all synthesized energetic compounds, including density, thermal stability and energetic performance, were investigated. The structure-property relationship was illustrated using two-dimensional fingerprint plots based on Hirshfeld surfaces, NCI plots and ESP of 7 and 7a. Among these energetic compounds, the hydroxylammonium salt 7b exhibited satisfactory calculated detonation performance (8700 m s-1), which was comparable to the commonly used highly explosive RDX (8748 m s-1). The potassium salt 5 was tested for its detonation ability by detonating RDX. The result indicates that compound 5 could be used as a potential green primary explosive.
RESUMEN
Several energetic materials, which are composed of furoxan and 1,2,4-oxadiazole backbones, were synthesized by nitrating 3,3'-bis(5-amino-1,2,4-oxadiazol-3-yl)-4,4'-azofuroxan (2) under 100 wt% HNO3 or 100 wt% HNO3/Ac2O followed by a cation metathesis. All synthesized compounds were fully characterized by multinuclear NMR spectroscopy, IR spectroscopy, and elemental analysis, while 3,3'-bis(1,2,4-oxadiazol-5(4H)-one-3-yl)-4,4'-azofuroxan (3) and diammonium 3,3'-bis(5-nitramino-1,2,4-oxadiazole-3-yl)-4,4'-azofuroxan (4a) were confirmed by single crystal X-ray diffraction. The physicochemical and energetic properties of these compounds including density, thermal stability and sensitivity were investigated. Compounds 3 and 4 have high densities (3: 1.90 g cm-3, 4: 1.92 g cm-3), which are comparable to that of HMX (1.91 g cm-3). All energetic compounds show relatively high calculated heat of formation in the range from 504.79 kJ mol-1 to 1405.62 kJ mol-1. Their detonation properties were evaluated by EXPLO5 code using the measured density and calculated heat of formation. Among them, compounds 3 and 4 have good detonation performance (3: D = 8891 m s-1, P = 34.7 GPa, 4: D = 9505 m s-1, P = 41.3 GPa) and acceptable sensitivities (3: IS = 10 J, 4: IS = 4 J), which indicate their potential applications as high-performance energetic materials.
