Search Results (21)

In this study, a C-C bond-linked triazole-fused oxadiazole energetic compound, 4-amino-5-(4-amino-1,2,5-oxadiazol-3-yl)-2,4-dihydro-3H-1,2,4-triazol-3-one (1), was successfully designed and efficiently synthesized. Following nitration, a functional group-modified nitramine energetic compound (2) was obtained, and its energetic ionic salt (3) was further prepared. A comprehensive characterization of the structures of these three compounds was conducted, resulting in the successful elucidation of the single-crystal structures of compound 2·Ca²⁺·6H₂O and compound 3·MeOH. Compound 2 exhibited a positive formation enthalpy (56.2 kJ·mol⁻¹) and moderate mechanical sensitivity (FS = 120 N, IS = 12 J). Due to the presence of the nitramine group, compound 2 exhibited a relatively low thermal decomposition temperature (T_dec = 94 °C). However, the thermal stability of compound 3 was significantly improved (T_dec = 233 °C), which is attributed to salt formation. Compound 3 exhibits a positive formation enthalpy (121.0 kJ·mol⁻¹), along with excellent detonation performance (D = 8120 m·s⁻¹, P = 32.1 GPa) and reduced mechanical sensitivity (FS = 224 N, IS = 24 J). Therefore, the multi-heterocyclic compound, joined via C-C bond linkage, demonstrates outstanding performance, offering a new avenue for the design and synthesis of energetic materials. Full article

Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) is a globally recognized energetic material that widely used in industrial, mining, and military fields. Like hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and other nitramine compounds, HMX has also been reported to exhibit neurotoxicity. However, the molecular mechanisms underlying the toxic effects of HMX remain poorly understood. Therefore, this study aims to investigate the neurotoxicity induced by HMX by adopting PC12 cells. The results show that HMX treatment decreased cell viability and upregulated the intracellular free calcium ions (Ca²⁺) in PC12 cells. Furthermore, HMX caused aggravated oxidative stress in PC12 cells, as evidenced by the upregulations of reactive oxygen species (ROS) and malondialdehyde (MDA). Intracellular biochemical assays demonstrated that HMX induced loss of mitochondrial membrane potential in PC12 cells. Notably, altered expression of brain-derived neurotrophic factor (BDNF) and ionotropic glutamate receptors (iGluRs), as well as an abnormal transcription profile, were also observed in PC12 cells treated by HMX. These findings suggest that HMX exerts toxic effects on PC12 cells, involved in oxidative stress, and disturbances in Ca²⁺ and BDNF, accompanied by aberrant iGluRs. Overall, the present study helps us better understand the health hazards associated with HMX and provides valuable insights for developing the health protection standards related to HMX exposure. Full article

The combustion behavior of various propellant samples, including double-base propellants, pressed nitramine powders, and modified double-base propellants containing nitramine, was examined using OH-PLIF technology. The combustion process took place within a combustion chamber, and images capturing the flame at the moment of stable combustion were selected for further analysis. The distribution and production rate of OH radicals in both the double-base propellant and the nitramine-modified double-base propellant were simulated using Chemkin-17.0 software. The outcomes from both the experimental and simulation studies revealed that the concentration of OH radicals increased with a higher content of NG in the double-base propellant. In the modified double-base propellant containing RDX, the OH radical concentration decreased as the RDX content increased, with these tendencies of change aligning closely with the simulation results. Full article

Glycidyl azide polymer (GAP)–energetic thermoplastic elastomer (GAP-ETPE) propellants have high development prospects as green solid propellants, but the preparation of GAP-ETPEs with excellent performance is still a challenge. Improving the performance of the adhesive system in a propellant by introducing a plasticizer is an effective approach to increasing the energy and toughness of the propellant. Herein, a novel high-strength solid propellant adhesive system was proposed with GAP-ETPEs as the adhesive skeleton, butyl nitrate ethyl nitramine (Bu-NENA) as the energetic plasticizer, and nitrocellulose (NC) as the reinforcing agent. The effects of the structural factors on its properties were studied. The results showed that the binder system would give the propellant better mechanical and safety properties. The results can provide a reference for the structure design, forming process, and parameter selection of high-performance GAP-based green solid propellants. Full article

This research was performed using Becke’s three-parameter hybrid functional approach with non-local correlation provided by Lee, Yang, and Parr and the cc-pVTZ basis set. The geometry, total energy, and heat of formation of the most stable conformers of the nitramines under study were obtained to obtain the density, resistance to shock stimuli, detonation pressure, and velocity of the materials under study. The results obtained allow us to predict new multipurpose energetic materials with a good balance between energy and stability. Our findings show that N-(2-nitroethyl)-N-(2,4,6-trinitrophenyl)nitramine, N-(2,4,6-trinitrophenyl)-N-[(3,4,5-trinitro-1H-pyrazol-1-yl)methyl]nitramine, N-(2,2-dinitroethyl)-N-(2,4,6-trinitrophenyl)nitramine, N-(2,2,2-trinitroethyl)-N-(2,4,6-trinitrophenyl)nitramine, and N-(trinitromethyl)-N-(2,4,6-trinitrophenyl)nitramine possess better explosive properties and a greater stability compared to tetryl, although they remain sensitive to shock stimuli. Referring to the results obtained, we recommend new tetryl analogs containing dinitroethyl, trinitroethyl, and trinitromethyl substituents for practical usage. Full article

A [3 + 2] cycloaddition reaction using dialkyne and diazide comonomers, both bearing explosophoric groups, to synthesize energetic polymers containing furazan and 1,2,3-triazole ring as well as nitramine group in the polymer chain have been described. The developed solvent- and catalyst-free approach is methodologically simple and effective, the comonomers used are easily available, and the resulting polymer does not need any purification. All this makes it a promising tool for the synthesis of energetic polymers. The protocol was utilized to generate multigram quantities of the target polymer, which has been comprehensively investigated. The resulting polymer was fully characterized by spectral and physico-chemical methods. Compatibility with energetic plasticizers, thermochemical characteristics, and combustion features indicate the prospects of this polymer as a binder base for energetic materials. The polymer of this study surpasses the benchmark energetic polymer, nitrocellulose (NC), in a number of properties. Full article

The investigation of a series of secondary aromatic nitramines was performed to reveal the impact of incremental methylene groups on the stability, shock impulse, and energetic properties of these compounds. Becke’s three-parameter hybrid functional approach with non-local correlation provided by Lee, Yang, and Parr and a cc-pVTZ basis set was used to obtain the geometry, total energy, and heat of formation of the most stable conformers of these aromatic nitramines. These parameters were used to evaluate the density, resistance to shock stimuli, detonation pressure, and velocity of the nitramines under study. Referring to the results obtained, we concluded that the thermal stability and resistance to shock stimuli of the compound investigated was directly CH₂ chain length-dependent, while their energetic- properties, such as detonation pressure and velocity, were worsened due to this chain increase. We also found that the stability of the compounds increases more significantly than the worsening energetic properties of aromatic nitramines. The results obtained reveal that in some cases the number of CH₂ in the chain should be smaller than three so that the explosive properties of the compounds under study would not be worse than TNT. Full article

The preparation and properties of a series of novel 1,3-dihydro-2H-benzimidazol-2-one nitro and nitramino derivatives are described. A detailed crystal structure of one of the obtained compounds, 4,5,6-trinitro-1,3-dihydro-2H-benzimidazol-2-one (TriNBO), was characterized using low temperature single crystal X-ray diffraction, namely an orthorhombic yellow prism, space group ‘P 2 21 21′, experimental crystal density 1.767 g/cm³ (at 173 K). Methyl analog, 5-Me-TriNBO-monoclinic red plates, space group, P 21/c, crystal density 1.82 g/cm³. TriNBO contains one activated nitro group at the fifth position, which was used for the nucleophilic substitution in the aminolysis reactions with three monoalkylamines (R=CH₃, C₂H₅, (CH₂)₂CH₃) and ethanolamine. The 5-R-aminoderivatives were further nitrated with N₂O₅/ HNO₃ and resulted in a new group of appropriate nitramines: 1,3-dihydro-2H-5-R-N(NO₂)-4,6-dinitrobenzimidazol-2-ones. Thermal analysis (TGA) of three selected representatives was performed. The new compounds possess a high melting point (200–315 °C) and thermal stability and can find a potential application as new thermostable energetic materials. Some calculated preliminary energetic characteristics show that TriNBO, 5-Me-TriNBO, 5-methylnitramino-1,3-dihydro-2H-4,6-dinitrobenzimidazol-2-one, and 5-nitratoethylnitramino-1,3-dihydro-2H-4,6-dinitrobenzimidazol-2-one possess increased energetic characteristics in comparison with TNT and tetryl. The proposed nitrocompounds may find potential applications as thermostable high-energy materials. Full article

Here, we investigated the reaction of 1,3-dipolar cycloaddition of 1,3-diazido-2-nitro-2- azapropane (DANP) to propargyl alcohol over a copper-based catalyst and identified the optimum reaction conditions that enable the synthesis of 2-nitro-1,3-bis(4,4′-dihydroxymethyl)-1,2,3-triazolyl-2-azapropane (1) in more than 84% yield. The reaction between DANP, 1,5-diazido-3-nitrazapentane, and phenylacetylene produced the respective 1,2,3-triazole derivatives in 83% and 71% yields, respectively. The structures of the resultant compounds were validated by infrared and NMR spectroscopies and elemental analysis. The structure of 1 was proved by single-crystal X-ray diffraction. This study demonstrated that 1 exhibits a dose-dependent antiarrhythmic activity towards calcium-chloride-induced arrhythmia and refers to Class III: moderately hazardous substances. Full article

A simple and fast procedure for estimation of the effect of chemical functionalization on the change in detonation properties of energetic materials is reported. The procedure consists of two levels. Computations at Level 1 can be performed with a pocket calculator. At Level 2, quantum-chemical calculations are needed, but these include only three computational tasks: vacuum-isolated molecule relaxation (PBE/DND) → crystal structure prediction (COMPASSII) → crystal cell relaxation (PBE/DND). Thus, we have analyzed transformation of both aromatic and aliphatic amines into the corresponding nitramines and diazo compounds. The calculations at Level 1 indicated that both crystal density (d_c) and solid-state enthalpy of formation (ΔH_f) are always positive and increase detonation properties, while the calculations at Level 2 revealed the amines that are the most sensitive to such chemical transformation. Full article

A simple, mild and general method has been developed for the preparation of alkyl nitramines bearing a halogenoalkoxylic moiety. From these reactive halogen intermediates, a few azidoalkoxyl alkyl nitramines have been produced as energetic plasticizers. This simple protocol allows azidonitramino ether plasticizers to be obtained from available precursors in high yields, as it is safe and viable for large-scale operations. The resulting products have been fully characterized by spectral methods, and their impact sensitivity, thermal transformations and burning properties were determined, thus allowing complete comparison to the analogues including other combinations of structural units. Such characterization of these new plasticizers illustrates the extent to which the nature and position of the functional units can be used to tune the above properties of these nitramines. All azidonitramino ethers are liquid with excellent energetic performance and are promising candidates for new environmentally friendly energetic materials. Full article

The research and development of rocket propellants with a high solid content and superior mechanical and security performance is urgently needed. In this paper, a novel extruded modified double-base (EMDB) rocket propellant plasticized by N-butyl-N-nitratoethyl nitramine (Bu-NENA) was prepared to overcome this challenge. The results indicated that Bu-NENA decreased the mechanical sensitivity successfully, contributing to the mechanical properties against traditional nitroglycerin (NG) based EMDB propellants, while hexogen (RDX), which is beneficial to propellant energy, was not conducive to the elongation and sensitivity of the propellants. By contrast with the blank group (NG-based EMDB propellant, R0), the elongation of the optimized propellant at −40 °C was promoted by 100% from 3.54% to 7.09%. Moreover, the β-transition temperature decreased from −33.8 °C to −38.1 °C due to superior plasticization by Bu-NENA, which represents a better toughness. The friction sensitivity dropped by 100% from 46% to 0%. Simultaneously, the height for 50% probability of explosion (H₅₀) increased by 87.2% from 17.2 cm to 32.2 cm. The results of this research could be used to predict a potential prospect in tactical weapons. Full article

Luminescent micelles are extensively studied molecular scaffolds used in applied supramolecular chemistry. These are particularly important due to their uniquely organized supramolecular structure and chemically responsive physical and optical features. Various luminescent tags can be incorporated with these amphiphilic micelles to create efficient luminescent probes that can be utilized as “chemical noses” (sensors) for toxic and hazardous materials, bioimaging, drug delivery and transport, etc. Due to their amphiphilic nature and well-defined reorganized self-assembled geometry, these nano-constructs are desirable candidates for size and shape complementary guest binding or sensing a specific analyte. A large number of articles describing micellar fluorogenic probes are reported, which are used for cation/anion sensing, amino acid and protein sensing, drug delivery, and chemo-sensing. However, this particular review article critically summarizes the sensing application of nitroaromatic (e.g., trinitrotoluene (TNT), trinitrobenzene (TNB), trinitrophenol (TNP), dinitrobenzene (DNB), etc.) and nitramine explosives (e.g., 1,3,5-trinitro-1,3,5-triazinane, trivially named as “research department explosive” (RDX), 1,3,5,7-tetranitro-1,3,5,7-tetrazocane, commonly known as “high melting explosive” (HMX) etc.). A deeper understanding on these self-assembled luminescent “functional materials” and the physicochemical behavior in the presence of explosive analytes might be helpful to design the next generation of smart nanomaterials for forensic applications. This review article will also provide a “state-of-the-art” coverage of research involving micellar–explosive adducts demonstrating the intermolecular charge/electron transfer (CT/ET) process operating within the host–guest systems. Full article

Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) a nitramine explosive, which has contaminated various military sites during its use, storage and manufacturing worldwide. As RDX is a recalcitrant, less soluble and toxic to human beings and other organisms, it is essential to remediate the contaminated sites. In the current investigation, authors have explored the potential of two indigenous microbes i.e., Bacillus toyonensis (isolate No. WS4-TSB-3, MTCC No. 12857) and Paenibacillus dendritiformis (isolate No. S10-TSA-3, MTCC No. 12859) isolated from an explosive manufacturing facility in north India, for the degradation of RDX in aqueous medium. Furthermore, RDX degradation has been optimized using response surface methodology (RSM) in a 15 days experiment at concentration of 20, 40, and 60 mg/L. It was found that various factors such as initial concentration of RDX, inoculum volume (2, 4 and 6%) and time (5, 10 and 15 days) had impact on transformation and degradation of contaminant. Samples were analyzed using high performance liquid chromatography (HPLC) and intermediate products were identified using LC-MS/MS. Maximum RDX removal of 81.6 ± 1.3 and 84.7 ± 0.9% for Bacillus toyonensis (isolate No. WS4-TSB-3) and Paenibacillus dendritiformis (isolate No. S10-TSA-3), respectively, was observed on 15th day at 40 mg/L initial concentration. During the degradation Hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX), Hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine (DNX), 4-Nitro-2,4-diazabutanal, Bis(hydroxymethyl)nitramine and nitrite were identified as intermediate products. The findings of the investigation suggest that both the microbes have the potential to degrade RDX in the aqueous medium and can be used for up-scaling the degradation of RDX on explosive contaminated sites. Full article

Cellulose acetate butyrate (CAB) is a widely used binder in polymer bonded explosives (PBXs). However, the mechanical properties of PBXs bonded with CAB are usually very poor, which makes the charge edges prone to crack. In the current study, seven plasticizers, including bis (2,2-dinitro propyl) formal/acetal (BDNPF/A or A3, which is 1:1 mixture of the two components), azide-terminated glycidyl azide (GAPA), n-butyl-N-(2-nitroxy-ethyl) nitramine (Bu-NENA), ethylene glycol bis(azidoacetate) (EGBAA), diethylene glycol bis(azidoacetate) (DEGBAA), trimethylol nitromethane tris (azidoacetate) (TMNTA) and pentaerythritol tetrakis (azidoacetate) [PETKAA], were studied for the plasticization of CAB. Molecular dynamics simulation was conducted to distinguish the compatibilities between CAB and plasticizers and to predict the mechanical properties of CAB/plasticizer systems. Considering the solubility parameters, binding energies and intermolecular radical distribution functions of these CAB/plasticizer systems comprehensively, we found A3, Bu-NENA, DEGBAA and GAPA are compatible with CAB. The elastic moduli of CAB/plasticizer systems follow the order of CAB/Bu-NENA>CAB/A3>CAB/DEGBAA>CAB/GAPA, and their processing property is in the order of CAB/Bu-NENA>CAB/GAPA>CAB/A3>CAB/DEGBAA. Afterwards, all the systems were characterized by FT-IR, differential scanning calorimetry (DSC), differential thermogravimetric analysis (DTA) and tensile tests. The results suggest A3, GAPA and Bu-NENA are compatible with CAB. The tensile strengths and Young’s moduli of these systems are in the order of CAB/A3>CAB/Bu-NENA>CAB/GAPA, while the strain at break of CAB/Bu-NENA is best, which are consistent with simulation results. Based on these results, it can be concluded that A3, Bu-NENA and GAPA are the most suitable plasticizers for CAB binder in improving mechanical and processing properties. Our work has provided a crucial guidance for the formulation design of PBXs with CAB binder. Full article