High Energetic Compounds Research Articles

Polynitropyrazole derivatives of pentanitroisowurtzitane

High energetic compounds of pentanitroisowurtzitane series containing various polynitropyrazolyl substituents attached to the frame through a methylene linker were synthesized in two steps from the corresponding NH precursors and paraformaldehyde. The structures of the compounds obtained were characterized by spectral methods, and their energy characteristics were estimated.

A π-Stacked Highly Stable, Insensitive, Energy-Containing Material with a Useful Planar Structure

Abstractπ-Stacking is common in materials, but different π–π stacking modes remarkably affect the properties and performances of materials. In particular, weak interactions, π-stacking and hydrogen bonding often have a significant impact on the stability and sensitivity of high-energetic compounds. A fused [5,7,5]-tricyclic energetic compound with a conjugated structure has been designed and synthesized. 4H-[1,2,5]Oxadiazolo[3,4-e][1,2,4]triazolo[3,4-g][1,2,4]triazepin-8-amine is obtained in 48% yield from 3-amino-4-carboxy-1,2,5-oxadiazole through an efficient two-step reaction. Owing to its layered planar structure and weak π interactions between layers, 4H-[1,2,5]oxadiazolo[3,4-e][1,2,4]triazolo[3,4-g][1,2,4]triazepin-8-amine exhibits high thermal stability (T d = 318 °C), low sensitivity (IS = 40 J, FS = 360 N), and relatively excellent detonation performance (D = 7059 ms–1, P = 20.2 GPa). This detonation performance is superior to that of the conventional explosive TNT. The developed procedure provides a new method for the synthesis of fused ring compounds.

Spectroscopic and imaging considerations of THz-TDS and ULF-Raman techniques towards practical security applications.

Nitrogen-containing high-energy organic compounds represent a class of materials with critical implications in various fields, including military, aerospace, and chemical industries. The precise characterization and analysis of these compounds are essential for both safety and performance considerations. Spectroscopic characterization in the far-infrared region has great potential for non-destructive investigation of high energetic and related compounds. This research article presents a comprehensive study of common organic energetic materials in the far-infrared region (5-200 cm-1), aiming to enhance security measures through the utilization of cutting-edge spectroscopic techniques. Broadband terahertz time-domain spectroscopy and ultra-low frequency Raman spectroscopy are employed as powerful tools to probe the vibrational and rotational modes of various explosive materials. One of the key objectives of this present work is unveiling the characteristic spectral features and optical parameters of five common nitrogen based high energy organic compounds towards rapid and accurate identification. Further, we have explored the potential of terahertz reflection imaging for non-contact through barrier sensing, a critical requirement in security applications. Based on the spectral features obtained from the spectroscopic studies and using advanced imaging algorithms we have been able to detect these compounds under various barriers including paper, cloth, backpack, etc. Subsequently, this study highlights the capabilities of the two techniques offering a pathway to enhance their utility over a wide range of practical security applications.

Harnessing triazole–oxadiazole–trinitromethyl moieties in the synthesis of insensitive energetic material with enhanced detonation performance

The nitrogen-and oxygen-rich azole-based high energetic compound 3,3′-(2-(trinitromethyl)-2H-1,2,3-triazole-4,5-diyl)-bis(1,2,4-oxadiazole) was synthesized from a readily accessible bis-cyano-substituted-azole in three steps with good yield.

Reinvestigating the synthesis and properties of high energetic MOFs based on 5,5′-bistetrazole-1,1′-diolate (BTO2−) and some transition metal cations (Pb2+, Cu2+ and Ag+)

5,5′-Bistetrazole-1,1′-diole (H2BTO), as a high energetic compound, is the precursor for the synthesis of insensitive high explosive (TKX-50, ABTOX and …). It is also considered as an attracting high nitrogen content ligand to prepare high energetic MOFs. Herein, H2BTO has been synthesized following a four steps method from glyoxal with an overall yield of 68%. Then, MOFs based on this ligand and Pb2+, Cu2+, and Ag+ have been prepared via hydrothermal method in a cylindrical glass pressure vessel at 130 °C. ICP-AES analysis confirms the composition of the produced MOFs as [Pb(BTO)(H2O)2]n, [Cu(BTO)(H2O)2]n and [Ag(HBTO)]n that, compared to the ligand precursor (H2BTO), are more dense and thermal stable but are more sensitive toward impact. Among these three MOFs, [Cu(BTO)(H2O)2]n present promising sensitivity properties (friction sensitivity >360 N and impact sensitivity of 28 J).

Understanding of the difference in packing density of some energetic isomers

This work describes the underlying mechanism for the packing density differences in energetic isomers and presents a strategy for constructing high density energetic compounds.

First-principles study on the mechanical and electronic properties of energetic molecular perovskites AM(ClO4)3 (A = C6H14N2 2+, C4H12N2 2+, C6H14N2O2+; M = Na+, K+).

Density functional theory (DFT) simulations were conducted to study the crystal structures, and mechanical and electronic properties of a series of new energetic molecular perovskites, including (C6H14N2)[Na(ClO4)3], (C6H14N2)[K(ClO4)3], (C4H12N2)[Na(ClO4)3] and (C6H14N2O)[K(ClO4)3], abbreviated as DAP-1, DAP-2, PAP-1, and DAP-O2, respectively. By calculating the elastic constants, moduli (Young's modulus E, bulk modulus B, and shear modulus G), Poisson ratio ν and Pugh's ratio B/G, we found that the four energetic molecular perovskites not only possessed good mechanical stability but excellent mechanical flexibility and ductility. In addition, DFT calculations were used to investigate the electronic properties of all of the perovskite compounds. The band gaps of DAP-1 and DAP-2 were comparable, and the band gap of PAP-1 was the smallest and that of DAP-O2 was the largest. A comprehensive analysis of the density of states and the M–O bonding characteristics provided a good explanation for the band gap characteristics. Besides, we found that the modulus properties of these molecular perovskite energetic compounds are also tightly bound to the strength of M–O bonding.

Feasibility of the Hybrid Use of Chlorella vulgaris Culture with the Conventional Biological Treatment in Urban Wastewater Treatment Plants

Currently, most wastewater treatment plants do not meet the legal requirements, especially regarding phosphorus and nitrogen contents. In this work, real primary urban wastewater (P-UW) was used as culture medium for the growth of Chlorella vulgaris. Experiments were carried out in batch photobioreactors at laboratory scale. To determine the maximum nutrient removal levels and the optimal pH value for C. vulgaris growth, the following pH values were studied: 5, 6, 7, 8, 9, 10, and 11. Additionally, two control experiments were conducted using UW and tap water at the same conditions but without microalgae inoculation. The operational conditions were agitation rate = 200 rpm, T = 25 °C, aeration rate = 0.5 L/min, and continuous light with illumination intensity = 359 µE m−2 s−1. Significant higher growth was obtained at pH = 7. The direct use of C. vulgaris for P-UW treatment demonstrated high removal percentages of organic (COD and BOD5 removal = 63.4% and 92.3%, respectively) and inorganic compounds (inorganic carbon removal = 99.6%). The final biomass was characterized by an accumulation of high energetic compounds, mainly carbohydrates, which ranged between 63.3% (pH = 5) and 82.8% (pH = 11) and represent a source of biofuels. These new achievements open up the possibility of new horizons in urban wastewater treatment.

Synthesis, Characterization and Decomposition of 4‐Diazo‐2,6‐dinitrophenol

AbstractA high energetic compound 4‐diazo‐2,6‐dinitrophenol was synthesized by employing one‐pot facile method from 4‐chloro‐3,5‐dinitroaniline. Its structure was characterized by Fourier transform infrared spectroscopy (FT‐IR), elemental analysis (EA), and nuclear magnetic resonance spectroscopy (1H NMR, 13C NMR and 15N NMR). The crystal structure was determined using an X‐ray single crystal diffractometer. The detonation properties of 4‐diazo‐2,6‐dinitrophenol and 6‐diazo‐3,5‐dichloro‐2,4‐dinitrophenol were compared by using Kamlet formula. Besides, the thermal behavior of 4‐diazo‐2,6‐dinitrophenol was analyzed by differential scanning calorimetry (DSC) and accelerating rate calorimeter (ARC), then according to the thermal analysis data, the thermal decomposition kinetics parameters were calculated using the thermal analysis data based on Kissinger method and Flynn‐Wall‐Ozawa method.

Series of AzTO-Based Energetic Materials: Effect of Different π-π Stacking Modes on Their Thermal Stability and Sensitivity.

π-Stacking is common in materials, but different π-π stacking modes remarkably affect the properties and performances of materials. In particular, weak interactions, π-stacking and hydrogen bonding, often have a great impact on the stability and sensitivity of high-energetic compounds. Therefore, several of energetic materials based on 1,1'-dihydroxyazotetrazole (1) with a nearly flat structure, such as the salts of aminoguanidine (2), 1,3-diaminoguanidine (3), imidazole (4), pyrazole (5) and triaminoguanidine (6), and a cocrystal of 2-methylimidazole (7), were designed and synthesized. Based on single-crystal diffraction data, thermal decomposition behaviors, and the mechanical sensitivity test, the compounds of 4, 5, and 7 with face-to-face π-π stacking display outstanding thermal stability and insensitivity.

Theoretical study on new high energetic density compounds with high power and specific impulse

In order to screen novel high energetic density compounds with high power and specific impulse, eight compounds containing an aza-cage or fused ring structure were designed. The B3PW91/6–31G(d,p) theoretical method was used to optimize their structures. Their power, specific impulse, impact sensitivity and the other detonation performance were predicted, and compared with that of HMX and CL-20. The results showed that the explosive powers and the specific impulses of all eight compounds were over 150 and 2.60 N s g−1, respectively, and higher than that of HMX and CL-20. Especially, the compd-1 and compd-4 compounds have excellent comprehensive performance.

Can the sensitivity of energetic materials be tuned by using hydrogen bonds? Another look at the role of hydrogen bonding in the design of high energetic compounds.

Strongly positive electrostatic potential in the central areas of molecules of energetic materials is one of the most important factors that determines the sensitivity of these molecules towards detonation. Quantum chemical and density functional theory calculations were used to reveal the influence of hydrogen bonding on the values of electrostatic potential above the central areas of molecules of three conventional explosives: 1,3,5-trinitrobenzene, 2,4,6-trinitrophenol, and 2,4,6-trinitrotoluene. Both the case when energetic molecules act as hydrogen atom donors and when they act as hydrogen atom acceptors were considered. Results of the calculations performed using the M06/cc-PVDZ level of theory showed that there are significant differences in the influence of hydrogen bonding on the electrostatic potential of energetic molecules acting as hydrogen atom donors and hydrogen atom acceptors. In the case when energetic molecules act as hydrogen acceptors, an increase of 10% in the strength of positive electrostatic potential was identified. In the case when energetic molecules act as hydrogen atom donors, a significant decrease (20-25%) in the strength of the positive potential on the molecular surface was calculated. These differences give an opportunity for fine-tuning the impact sensitivities of energetic compounds and provide new guidelines for the design of explosives with desirable characteristics.

Advanced crystalline energetic materials modified by coating/intercalation techniques

• The coating/intercalation techniques for crystalline energetic materials (EMs) are summarized. • The coating/intercalation may improve the stability, decrease the sensitivity and hygroscopicity of EMs. • The effects of coating agents and relevant fabrication techniques on reactivity of typical energetic crystals are included. In the field of energetic materials (EMs), the problems of sensitivity and relatively high cost limit their practical applications in certain conditions. Therefore, various newly developed high energetic compounds are still not in use. The balance between the energy density and safety of EMs remains a highly challenging task. Numerous strategies have been implemented to achieve this balance. The most typical ones are coating, intercalation, recrystallization, cocrystallization, hybridization and chemical grafting methods. Of all the mentioned modification methods, the coating/intercalation have been found to be the best and the most widely used ones, due to their safer but cost-effective operations with well-controlled procedures, which may result in products with tunable properties. In cases of coating/intercalation of energetic crystals, different coating agents and fabrication techniques, including the well-known water suspension, in-situ polymerization, physical vapor deposition (PVD) and chemical vapor deposition (CVD) have been applied to improve the thermal stability and mechanical sensitivity reduction of energetic crystals. The results show that the mechanical sensitivity and performances could be well-balanced in this way. This review summarizes the preparation methods and fundamental properties of coated/intercalated crystalline EMs. It demonstrates that the EMs with better performances could be made by appropriate modification methods, where the modified ammonium salts and nitramine crystals are presented as typical examples.

Experimental and Theoretical Study on the Stability of CL-20-Based Host-Guest Energetic Materials.

CL-20-based host-guest complexes are promising energetic materials, which are prepared by embedding small molecules into the crystal lattice cavity of anhydrous CL-20. The structure, interaction, stability, and detonation performance of a series of host-guest complexes were investigated by the combination method of density functional theory and experiment. Both the crystal structure of α-CL-20/H2O and α-CL-20/N2O revealed by powder X-ray diffraction and the thermal stability order of α-CL-20/N2O, α-CL-20/CO2, α-CL-20/H2O, and α-CL-20/H2O2 measured using a differential scanning calorimeter show excellent accordance between experimental results and simulative predication. Thus, the reliability of the calculation method can be judged by the result of this comparison. The stability of different host-guest structures was compared under vacuum, and the influence of intermolecular interactions on the structural stability was discussed. In view of the various factors affecting the performance of high-energy explosives, such as detonation performance, thermal stability, and density, we conclude that α-CL-20/O3 could be regarded as a potential target high-energetic compound. On the basis of the above results, this calculation method can provide a theoretical basis for the preparation of CL-20-based host-guest energetic compounds.

The Effects of Metal Complexes of Nano-Graphene Oxide to Thermal Decomposition of FOX-7.

1,1-diamino-2,2-dinitroethene (FOX-7) an insensitive high-energetic compound, has rarely been reported previously with respect to combustion performance. In order to quickly apply it to propellants, the thermal decomposition behaviors of FOX-7 should be optimized. Metal complexes of nano-graphene oxide have an obvious effect on the thermal decomposition of energy materials. In this paper, the metal (Cu2+ and Fe3+) complexes of nano-graphene oxide (nGO) have been synthesized using nGO as a ligand and metal ions as a coordination center. They were mixed with FOX-7 as additives to form energetic composites, and the chemical bond distributions and thermal decomposition processes of these composites have been investigated. The results show that Cu2+ and Fe3+ are uniformly distributed on the surface of the nGO. The thermal decomposition processes of nGO-metal-FOX-7 composites have been fully characterized by Differential scanning calorimeter (DSC) and Thermal gravimetric analyzer-Differential scanning calorimeter-Infrared spectroscopy-Mass spectrum (TG-DSC-IR-MS) coupling technology. The results show that the Fe3+ based complex affect the decomposition of FOX-7 than the Cu2+ based one with the initial decomposition temperature of 230 °C and the apparent heat release of 3535.6 J·g−1. Moreover, the addition of nGO-metal complexes could promote the formation of nitrogen during the decomposition of FOX-7, indicating a more complete decomposition.

Crystal structure evolution of the high energetic compound carbonic dihydrazidinium bis[3-(5-nitroimino-1,2,4-triazolate)] induced by solvents

Four new solid forms of CBNT including CBNT·2H2O, H2BNT·2DMSO, H2BNT·2H2O and [NH2(CH3)2+]2[BNT2−]·2H2O were successfully obtained from water, DMSO, BL/H2O and DMF/H2O through a solvent induction method.

Effects of Nanosized Metals and Metal Oxides on the Thermal Behaviors of Insensitive High Energetic Compound ICM-102

In this paper, the composites of a newly insensitive high explosive 2,4,6-triamino-5-nitropyrimidine-1,3-dioxide (ICM-102) with nanosized metals (Al, Co, Mg, Si, Ti, and Zr) and nanosized metal oxides (CuO and Fe2O3) have been prepared and investigated in terms of thermal reactivity. The catalytic effects on the thermal decomposition of ICM-102 composites have been investigated by TGA-DSC technique. Among all the composites, ICM-102/Co shows the minimum residue rate of 1.57 wt % and ICM-102/Si shows the maximum heat release of 1001.9 J g–1. The kinetic parameters for the catalytic decomposition of ICM-102 have been obtained. The activation energy (Ea) of ICM-102 decomposition is within 197.9–212.0 kJ mol–1. Compared with ICM-102, the Ea of ICM-102/Si decomposition was decreased by about 90 kJ mol–1. The decomposition gaseous products of ICM-102 and its composites have been analyzed by the TG-MS technique. It has been shown that the main gaseous products are H2O, C2H4, C3, and C2N or C3H2. The ICM-102 deco...

Engineering the Morphology and Particle Size of High Energetic Compounds Using Drop-by-Drop and Drop-to-Drop Solvent-Antisolvent Interaction Methods.

Morphology-controlled precipitation of three powerful organic high energetic compounds (HECs) viz. cyclotrimethylenetrinitramine (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), and 2-methyl-1,3,5-trinitrobenzene (TNT) was achieved by two different processes, namely, drop-by-drop (DBD) and drop-to-drop (DTD) solvent–antisolvent interaction methods. Effect of different experimental parameters on the mean size and morphology of the prepared submicron-sized particles of HECs was investigated thoroughly. The DBD method favors the formation of nanosized particles of RDX and TNT at lower concentrations (5 mM). However, a significant increase in the mean particle size occurred at higher concentrations (25 and 50 mM). Formation of facetted crystals of RDX, HMX, and nanorods of TNT was observed at higher concentrations because of the interaction of crystal facets with the antisolvent. Relatively, smaller sized, spherical particles of RDX and HMX could be prepared through the DTD method even at higher concentrations (25 mM). The DTD method is a continuous process and hence is a facile method for industrial applications. X-ray diffraction and Fourier transform infrared spectroscopy studies revealed that RDX, HMX and TNT were precipitated in their most stable polymorphic forms α, β, and monoclinic, respectively. Differential scanning calorimetry showed that the thermal response of the nano-HECs was similar to the respective raw-HECs. A slight decrease in crystallinity and the melting point was observed because of the decrease in the mean particle size.

Novel Organic Compounds Containing Nitramine Groups Suitable as High‐Energy Cyclic Nitramine Compounds

AbstractThis work introduces eight novel cyclic nitramine derivatives of energetic compounds as high performance energetic compounds. Assessments of physicothermal, detonation and combustion properties as well as sensitivities with respect to external stimuli impact, friction and shock are done for these compounds. The method of density functional theory (DFT) at B3LYP/6‐31G (d,p) as well as the best available predictive methods are used for prediction of 20 different parameters including crystal density, solid phase heat formation, Gibbs free energy of formation, activation energy, heat of sublimation, melting point, enthalpy of fusion, entropy of fusion, heat of combustion, heat of detonation, temperature of detonation, specific impulse, velocity of detonation, detonation pressure, Gurney velocity, power, brisance, heat sensitivity, impact sensitivity, friction sensitivity and shock sensitivity. These properties are compared with corresponding measured or calculated data of octahydro‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine (HMX) and 2,4,6,8‐tetranitro‐1H,5H‐2,4,6,8‐tetraazabicyclo [3.3.0] octane (BCHMX) as two high performance nitramines. Among the introduced cyclic nitramines, it shown that N,N‐bis(1,3,4,6‐tetranitrooctahydroimidazo[4, 5‐d]imidazol‐2‐yl) nitramide is a good candidate of high performance nitramine where its sensitivity with respect to impact, friction and shock is close to BCHMX.

Azasydnone – novel “green” building block for designing high energetic compounds

The azasydnone unit is a promising explosophoric block for future generations of highly thermostable and dense energetic materials.