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1.
Isomers of 4‐amino‐1,3‐dinitrotriazol‐5‐one‐2‐oxide (ADNTONO) are of interest in the contest of insensitive explosives and were found to have true local energy minima at the DFT‐B3LYP/aug‐cc‐pVDZ level. The optimized structures, vibrational frequencies and thermodynamic values for triazol‐5‐one N‐oxides were obtained in their ground state. Kamlet‐Jacob equations were used to evaluate the performance properties. The detonation properties of ADNTONO (D=10.15 to 10.46 km s−1, P=50.86 to 54.25 GPa) are higher compared with those of 1,1‐diamino‐2,2‐dinitroethylene (D=8.87 km s−1, P=32.75 GPa), 5‐nitro‐1,2,4‐triazol‐3‐one (D=8.56 km s−1, P=31.12 GPa), 1,2,4,5‐tetrazine‐3,6‐diamine‐1,4‐dioxide (D=8.78 km s−1, P=31.0 GPa), 1‐amino‐3,4,5‐trinitropyrazole (D=9.31 km s−1, P=40.13 GPa), 4,4′‐dinitro‐3,3′‐bifurazan (D=8.80 km s−1, P=35.60 GPa) and 3,4‐bis(3‐nitrofurazan‐4‐yl)furoxan (D=9.25 km s−1, P=39.54 GPa). The  NH2 group(s) appears to be particularly promising area for investigation since it may lead to two desirable consequences of higher stability (insensitivity), higher density, and thus detonation velocity and pressure.  相似文献   

2.
Two new highly stable energetic salts were synthesized in reasonable yield by using the high nitrogen‐content heterocycle 3,4,5‐triamino‐1,2,4‐triazole and resulting in its picrate and azotetrazolate salts. 3,4,5‐Triamino‐1,2,4‐triazolium picrate (1) and bis(3,4,5‐triamino‐1,2,4‐triazolium) 5,5′‐azotetrazolate (2) were characterized analytically and spectroscopically. X‐ray diffraction studies revealed that protonation takes place on the nitrogen N1 (crystallographically labelled as N2). The sensitivity of the compounds to shock and friction was also determined by standard BAM tests revealing a low sensitivity for both. B3LYP/6–31G(d, p) density functional (DFT) calculations were carried out to determine the enthalpy of combustion (ΔcH (1) =−3737.8 kJ mol−1, ΔcH (2) =−4577.8 kJ mol−1) and the standard enthalpy of formation (ΔfH° (1) =−498.3 kJ mol−1, (ΔfH° (2) =+524.2 kJ mol−1). The detonation pressures (P (1) =189×108 Pa, P (2) =199×108 Pa) and detonation velocities (D (1) =7015 m s−1, D (2) =7683 m s−1) were calculated using the program EXPLO5.  相似文献   

3.
Finding new insensitive high explosives has been the focus of the energetic materials community in recent decades. To accelerate the discovery process, it is necessary to elucidate the relationship between molecular structure and the performance of explosives. In this regard, the effects of N-oxide groups, commonly introduced to increase the energy density of explosives, on the thermal stability of explosives were investigated by comparing the thermal behaviors of a typical energetic N-oxide, ANPZO, and its analogue ANPZ. The presence of N-oxide facilitated the thermal decomposition of ANPZO thoroughly and suppressed its sublimation to a certain extent. Compared to ANPZ, the introduction of N-oxide increased the thermal enthalpy, reduced the solid residues, and shortened the acceleration period of thermal decomposition of ANPZO. Additionally, the sublimation rate and vapor pressure of ANPZO were lower than those of ANPZ. The enthalpy of sublimation for ANPZO was 175.1 kJ mol−1, compared to 135.2 kJ mol−1 for ANPZ. The effects of N-oxide on the thermal decomposition and sublimation are attributed to its contribution to the augmentation of oxygen sources and intermolecular interactions, respectively. This study provides further insight into the relationship between the N-oxide group and the performance of explosives, which could be beneficial for the design and application of new explosives.  相似文献   

4.
Some thermodynamic and explosive properties of the recently reported 1‐azido‐2‐nitro‐2‐azapropane (ANAP) have been determined in a combined computational ab initio (MP2/aug‐cc‐pVDZ) and EXPLO5 (Becker–Kistiakowsky–Wilson's equation of state, BKW EOS) study. The enthalpy of formation of ANAP in the liquid phase was calculated to be ΔfH°, ANAP(l)=+297.1 kJ mol−1. The heat of detonation (Qv), the detonation pressure (P), and the detonation velocity of ANAP were calculated to be Qv=−6088 kJ kg−1, P=23.8 GPa, D=8033 m s−1. A mixture of ANAP and tetranitromethane (TNM) was investigated in an attempt to tailor the impact sensitivity of ANAP, but results obtained indicate that the mixture is almost as sensitive as pure ANAP. On the other hand, ANAP and TNM were found to be chemically compatible (1H, 13C, 14N NMR; DSC) and a 1 : 1 mixture (by weight) of both components was calculated to have superior explosive properties than either of the individual components: Qv=−6848 kJ kg−1, P=27.0 GPa, D=8284 m s−1.  相似文献   

5.
We performed theoretical studies to predict the molecular structure, molecular properties, and explosive performance of 4,4′,5,5′‐tetranitro‐2,2′‐bi‐1H‐imidazole (TNBI). High levels of ab initio and density functional theories were employed to predict the molecular structure of TNBI. Predicted TNBI structure was in good agreement with that observed by X‐ray crystallography. Heat of formation in the solid phase at 298 K was predicted to be 270.3 kJ/mol. Density of TNBI was predicted to be 1.919–1.956 g/cm3 depending upon the parameter sets of group additivity method. By using these values as input data, we estimated detonation velocity and C–J pressure to be 8.69–8.80 km/s and 34.5‐36.1 GPa, respectively. Impact sensitivity of TNBI was predicted to be 33 cm.  相似文献   

6.
HTPB/CL‐20 castable booster explosives were prepared successfully by a cast‐cured process. Scanning electron microscope (SEM) and the charge density test were employed to characterize the molding effect of HTPB/CL‐20 explosives. The propagation reliability, detonation velocity, mechanical sensitivity, thermal decomposition characteristics and thermal stability of the HTPB/CL‐20 explosives were also measured and analyzed. The results show that, when CL‐20 content is less than 91 wt.‐%, the charges with better molding effect were obtained easily. The critical diameter of HTPB/CL‐20 explosives is less than 1 mm, which exhibits good propagation reliability. When the density of HTPB/CL‐20 charge with 91 wt.‐% CL‐20 is 1.73 g cm−3, its detonation velocity can reach 8273 m s−1. Moreover, this kind of explosives has low mechanical sensitivity and good thermal stability.  相似文献   

7.
Density functional theory (DFT) calculations were performed for a series of polynitrobenzene derivatives. Some nitrobenzenes with amino groups attached were also investigated as a benchmark or as a precursor. Heats of formation (HOF) were evaluated. The isodesmic reactions used for the prediction of HOFs are of permutation type in terms of the substituents. The HOFs increase non‐additively with increasing number of nitro groups. The attachment of the amino groups to polynitrobenzenes dramatically decreases the HOF. The HOF of hexanitrobenzene (HNB) is 344.05 kJ mol−1 at the B3LYP/6‐311+G** level. This value is much larger than that of the widely used 1,3,5‐triamino‐2,4,6‐trinitrobenzene (TATB), which engenders HNB a large chemical energy of detonation. The strengths of the group interactions were analyzed according to the disproportionation energy. The nearest‐neighbor interactions in polynitrobenzenes are in the range of 27.20–55.90 kJ mol−1. The energy barrier for the internal rotation of nitro group in nitrobenzene is 24.6 kJ mol−1. However, the energy barrier for the internal rotation of 2‐position nitro group of 1,2,3‐trinitrobenzene is as large as 216.3 kJ mol−1. The chemical energies of detonation for polynitrobenzenes with three or more nitro groups are over 6000 J g−1. Pentanitroaniline and HNB have good performances in terms of detonation velocity and pressure.  相似文献   

8.
The geometries of polynitropyrazines and their N‐oxides have been fully optimized employing the density functional B3LYP method and the 6‐31++G** basis set. For polynitropyrazines and their N‐oxides we have obtained the enthalpies of formation (at p=1.013×105 Pa and T=298.15 K) by designing isodesmic reactions and the detonation velocities by using the Stine method. Calculated results show that the aromaticity of the pyrazine ring of polynitropyrazine is lower than that of its N‐oxide. From the acquired relationship between the experimental impact sensitivity H50 (12B type) and the least C NO2 bond order the predicted H50 values for compounds 2,5‐diamino‐3,6‐dinitropyrazine and 2,5‐diamino‐3,6‐dinitropyrazine‐1‐oxide are 83 cm and 59 cm, respectively, implying that they are low sensitive explosives. The enthalpy of formation of polynitropyrazine is much less than that of its N‐oxide. The calculated density (1.90 g/cm3) for 2,6‐diamino‐3,5‐dinitropyrazine‐1‐oxide (LLM‐105) is close to the experimental value (1.918 g/cm3), and from both sensitivity and detonation velocity it has been deduced that LLM‐105 is superior to other diaminodinitropyrazines and their N‐oxides. The largest density and detonation velocity obtained in this work are 2.02 g/cm3 (2‐amino‐3,5,6‐trinitropyrazine) and 9.34 km/s (2,3,5,6‐tetranitropyrazine), respectively.  相似文献   

9.
Perfusion explosives were prepared using porous SF‐3 propellants, which were synthesized by a supercritical fluid foaming process. Scanning electron microscopy (SEM) was used to characterize the porous SF‐3 propellants. Massive holes were generated after the foaming process. The density of perfusion explosives using foamed SF‐3 propellants exceeds 1.3 g cm−3, and the detonation velocities exceed 6000 m s−1. Underwater energy tests and high‐speed photography were carried out to investigate the detonation performance of perfusion explosives. The results showed that perfusion explosives using unfoamed SF‐3 propellants could not be detonated. However, perfusion explosives using their foamed analogs could be detonated herein.  相似文献   

10.
Plastic explosives based on different cyclic nitramines with different polymeric matrices were prepared and studied. The used polymeric matrices were fabricated on the basis of polyisobutylene (PIB), acrylonitrile‐butadiene rubber (ABR), Viton A, and polydimethyl‐siloxane as binders, whereas the nitramines named RDX (1,3,5‐trinitroperhydro‐1,3,5‐triazine), β‐HMX (β‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine), BCHMX (cis‐1,3,4,6‐tetranitrooctahydroimidazo‐[4,5‐d]imidazole) and ε‐HNIW (ε‐2,4,6,8,10,12‐hexanitro‐2,4,6,8,10,12‐hexaazaisowurtzitane) were used as explosive fillers. Commercial Semtex 10, based on pentaerythritol tetranitrate (PETN), was used for comparison. Impact sensitivity, loading density, ρ, detonation velocity, D, and relative explosive strength (RS) measured by ballistic mortar were determined. It was concluded that plastic BCHMX based on Viton A or PIB‐matrix exhibits higher RS compared with PBXs based on RDX and HMX. Correlations between RS and the impact sensitivity, the ρD2 term and the square of the detonation velocity were studied and discussed. The results confirm the well‐known fact that increasing the performance is usually accompanied by an increase in the sensitivity of the explosives. In this connection, Viton A enables achieving a high RS, but with a relatively high sensitivity of the PBXs, whereas the polydimethyl‐siloxane matrix should perhaps give PBXs with optimum explosive strength and sensitivity parameters.  相似文献   

11.
Molecular orbital calculations were performed for the geometric and electronic structures, band gap, thermodynamic properties, density, detonation velocity, detonation pressure, stability and sensitivity of 1,3,4,5‐tetranitropyrazole ( R23 ). The calculated density (approx. 2060 kg m−3), detonation velocity (approx. 9.242 km s−1) and detonation pressure (approx. 41.30 GPa) of the model compound are appearing to be promising compared to hexahydro‐1,3,5‐trinito‐1,3,5‐triazine (RDX) and octahydro‐1,3,5,7‐tetranitro‐l,3,5,7‐tetrazocine (HMX). Bader’s atoms‐in‐molecules (AIM) analysis was also performed to understand the nature of the intramolecular N ⋅⋅⋅ O interactions and the strength of trigger X NO2 bonds (where XC, N) of the optimized structure computed from the B3LYP/aug‐cc‐pVDZ level.  相似文献   

12.
We have applied thermal insults on LX‐04 at 185 °C and found that the material expanded significantly, resulting in a bulk density reduction of 12%. Subsequent detonation experiments (three cylinder tests) were conducted on the thermally damaged LX‐04 samples and pristine low‐density LX‐04 samples and the results showed that the fractions reacted were close to 1.0. The thermally damaged LX‐04 and pristine low‐density LX‐04 showed detonation velocities of 7.7–7.8 mm μs−1, significantly lower than that (8.5 mm μs−1) of pristine high‐density LX‐04. Detonation energy densities for the damaged LX‐04, low‐density pristine LX‐04, and hot cylinder shot of LX‐04 were 6.48, 6.62, and 6.58 kJ cm−3, respectively, lower than the detonation energy density of 8.11 kJ cm−3 for the high density pristine LX‐04. The break‐out curves for the detonation fronts showed that the damaged LX‐04 had longer edge lags than the high density pristine LX‐04, indicating that the damaged explosive is less ideal.  相似文献   

13.
Four plastic explosives based on cyclic nitramines and polymeric matrix were prepared and studied. The nitramines were RDX (1,3,5‐trinitro‐1,3,5‐triazinane), HMX (1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocane), BCHMX (cis‐1,3,4,6‐tetranitro‐octahydroimidazo‐[4,5‐d]imidazole), and ϵ‐CL20 (ϵ‐2,4,6,8,10,12‐hexanitro‐2,4,6,8,10,12‐hexaazaisowurtzitane, ϵ‐HNIW). Sylgard 184 was used in the all PBXs prepared samples as a binder. The sensitivities to different mechanical stimuli were determined. The detonation velocities were experimentally measured. Detonation characteristics were calculated by EXPLO5 thermodynamic code. For comparison, standard plastic explosives, Composition C4, Semtex 10, and EPX‐1 were studied. Results showed that the experimental detonation velocities as well as the calculated detonation parameters decrease in the following order: CL20‐sylgard>HMX‐sylgard≥BCHMX‐sylgard>RDX‐sylgard. Calculations by EXPLO5 computer program resulted in detonation velocities close to the experimental ones with 3.1 % maximum difference. Urizar coefficient for the Sylgard binder was calculated from experimental data. An inverse linear relationship between friction sensitivity and heat of detonation of the studied samples was observed. Sylgard binder significantly decreased the sensitivity of all the studied nitramines. Among these prepared samples, the properties of BCHMX‐sylgard are similar to other ordinary plastic explosives.  相似文献   

14.
The present investigation is about the determination of the gas phase concentration parameters of the notorious explosives triacetone triperoxide (TATP, 1 ) and diacetone diperoxide (DADP, 2 ), which have been frequently used in improvised explosive devices. According to calculations with EXPLO5 the energetic performance of both explosives is similar. The enthalpy of sublimation (298.15 K) ( 1 : 76.7±0.7 kJ mol−1; 2 : 75.0±0.5 kJ mol−1) and vapor pressures (298.15 K) ( 1 : 6.7 Pa, 2 : 26.6 Pa) of both compounds have been studied using the transpiration method in the ambient temperature range of 274–314 K. The results obtained in this work were compared critically with the existing literature values. Data for DADP ( 2 ) mostly shows agreement with literature ones. However data of TATP ( 1 ) obtained in this work revealed insufficient agreement of all sets of data available in literature, which might be explained by the rich polymorphism of TATP 1 . The saturation and diffusion equilibrium concentration of both analytes was calculated at 298.15 K. In comparison to the saturation equilibrium concentration measured in this work ( 1 : 600 μg L−1, 2 : 1589 μg L−1) the corresponding estimated diffusion condition air concentrations ( 1 : 3.1 ng L−1, 2 : 10 ng L−1, for a surface of 200 cm2) are lower by five orders of magnitude.  相似文献   

15.
At present, cis‐1,3,4,6‐tetranitro‐octahydroimidazo‐[4,5‐d]imidazole (bicyclo‐HMX, BCHMX) and ε‐2,4,6,8,10,12‐hexanitro‐2,4,6,8,10,12‐hexaazaisowurtzitane (ε‐HNIW, CL‐20) are a topic of interest from the attractive and the potentially attainable nitramines. They were chosen to be studied in comparison with 1,3,5‐trinitro‐1,3,5‐triazinane (RDX) and β‐1,3,5,7‐tetranitro‐1,3,5‐tetrazocane (β‐HMX). Marginal attention is devoted also to 4,8,10,12‐tetranitro‐2,6‐dioxa‐tetraazawurtzitane (Aurora 5). BCHMX, ε‐HNIW, RDX, and HMX were studied as plastic bonded explosives (PBXs) with elastic properties based on Composition C4 and Semtex 10 matrices. Also they were studied as a highly pressed PBXs based on the Viton A binder. The detonation parameters and sensitivity aspects of these nitramines and their corresponding PBXs were determined. Relative explosive strengths (RS) of these compositions are mentioned with mutual relationships between the measured RS values and some detonation parameters. These relationships indicate a possibility of changes in detonation chemistry of these mixtures filled mainly by HNIW. A sensitivity of RS‐CL20 (HNIW with reduced sensitivity) is reported and the new findings in the friction sensitivity are discussed.  相似文献   

16.
This paper introduces five novel high‐nitrogen content (N>50%) tetrazole derivatives with desirable physicothermal properties, high detonation and combustion performance as well as suitable sensitivities with respect to external stimuli electric spark and heat. Suitable density functional theory (DFT) and empirical methods were used to predict their crystal density, melting point, condensed phase heat of formation, enthalpy of fusion, Gibbs free energy of formation, velocity of detonation, detonation pressure, Gurney velocity, heat of detonation, power (strength), brisance, impact sensitivity, electric spark sensitivity, heat sensitivity and specific impulse. Two compounds 5,5′‐[(1Z,5Z)‐3,4‐dinitrohexaaza‐1,5‐diene‐1,6‐diyl]bis(1‐nitro‐1H‐tetrazole) and 3,3′,7,7′‐tetranitro‐3,3a,3′,3′a‐tetrahydro‐7H,7′H‐6,6′‐bitetrazolo[1,5‐e]pentazine as compared to the other new derivatives can be introduced as high performance explosives for confined explosion and oxidizers in solid propellants.  相似文献   

17.
Micrometer‐sized aluminum is widely used in energetics; however, performance of propellants, explosives, and pyrotechnics could be significantly improved if its ignition barriers could be disrupted. We report morphological, thermal, and chemical characterization of fuel rich aluminum‐polytetrafluoroethylene (70–30 wt‐%) reactive particles formed by high and low energy milling. Average particle sizes range from 15–78 μm; however, specific surface areas range from approx. 2–7 m2 g−1 due to milling induced voids and cleaved surfaces. Scanning electron microscopy and energy dispersive spectroscopy reveal uniform distribution of PTFE, providing nanoscale mixing within particles. The combustion enthalpy was found to be 20.2 kJ g−1, though a slight decrease (0.8 kJ g−1) results from extended high energy milling due to α‐AlF3 formation. For high energy mechanically activated particles, differential scanning calorimetry in argon shows a strong, exothermic pre‐ignition reaction that onsets near 440 °C and a second, more dominant exotherm that onsets around 510 °C. Scans in O2‐Ar indicate that, unlike physical mixtures, more complete reaction occurs at higher heating rates and the reaction onset is drastically reduced (approx. 440 °C). Simple flame tests reveal that these altered Al‐polytetrafluoroethylene particles light readily unlike micrometer‐sized aluminum. Safety testing also shows these particles have high electrostatic discharge (89.9–108 mJ), impact (>213 cm), and friction (>360 N) ignition thresholds. These particles may be useful for reactive liners, thermobaric explosives, and pyrolants. In particular, the altered reactivity, large particle size and relatively low specific surface area of these fuel rich particles make them an interesting replacement for aluminum in solid propellants.  相似文献   

18.
Four plastic explosives based on energetic nitramines and a non‐energetic binder were prepared and studied. The nitramines were RDX (1,3,5‐trinitro‐1,3,5‐triazine), HMX (1,3,5,7‐tetranitro‐1,3,5,7‐tetrazine), BCHMX (cis‐1,3,4,6‐tetranitro‐octahydroimidazo‐[4,5‐d]imidazole) and HNIW (ε‐2,4,6,8,10,12‐hexanitro‐2,4,6,8,10,12‐hexaazaisowurtzitane, ε‐CL‐20). The binder was in all cases polyisobutylene (PIB) as in the standard composition C‐4. These powerful plastic explosives were compared to standard PETN‐based commercially available explosives Semtex 1A and Sprängdeg m/46. The detonation velocities were experimentally measured and compared to the ones calculated by the Kamlet–Jacobs method, CHEETAH and EXPLO5 Codes. The experimental detonation velocities as well as the calculated detonation parameters decrease in the following order: HNIW‐PIB>HMX‐PIB≥BCHMX‐PIB>RDX‐PIB>Sprändeg m/46≥Semtex 1A. Urizar coefficients for the various binders were calculated from experimental data.  相似文献   

19.
The design and synthesis of new environmentally friendly energetic materials with excellent performance and reliable safety have received considerable attention. A new energetic salt of semicarbazide 5‐dinitromethyltetrazolate (SCZ ⋅ DNMZ) was synthesized by using semicarbazide and 5‐dinitromethyltetrazolate (DNMZ) as raw materials, and fully characterized by using elemental analysis, FT‐IR spectroscopy, 1H, 13C, and 15N nmR and mass spectrometry. The monocrystal of the salt was obtained and the structure was determined by X‐ray single‐crystal diffractometer. Results show that it belongs to monoclinic space group P 21/c with a high density of 1.867 g cm−3. The thermal decomposition behavior was tested by DSC and TG‐DTG technologies; the non‐isothermal kinetic parameters for the salt were calculated. The enthalpy of formation for the salt is directly dependent on the combustion heats data with a result of 341.5 kJ mol−1, which is about three times higher than that of RDX. The detonation pressure (P ) and detonation velocitiy (D ) of the salt were determined as 8931 m s−1 and 36.2 GPa, which are also higher than that of RDX. The impact sensitivity was tested with a result of 10.8 J. We can draw a safe conclusion that the salt has provided a promising future by using as a kind of explosive alternative. The discovery also contributes significantly to the expansion and application of the N‐heterocyclic compounds applied as energetic materials.  相似文献   

20.
The novel, thermally stable explosive 4,4′‐((2,4,6‐trinitro‐1,3‐phenylene)bis(oxy))bis(1,3‐dinitrobenzene) (Be referred to as ZXC‐ 5 in our laboratory) has been reported. ZXC‐5 can be synthesized by a simple synthetic method (The total synthesis of ZXC‐ 5 requires only two steps and the total yield of ZXC‐ 5 is more than 89 %) and shows the superior detonation performances (detonation pressure, detonation velocity, sensitivity toward mechanical stimuli, and temperature of decomposition). The structure of ZXC‐5 was characterized by multinuclear (1H, 13C) NMR and mass spectrometry. The structure in the crystalline state was confirmed by low‐temperature single‐crystal X‐ray diffraction. From the calculated standard molar enthalpy of formation and the measured densities, the detonation properties were predicted by using the EXPLO5 V6.01 thermochemical computer code. The sensitivity of ZXC‐ 5 towards impact, electrostatic discharge, and friction were also measured.  相似文献   

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