Calculated Detonation Velocity Research Articles

Highly Thermostable and Insensitive Energetic Hybrid Coordination Polymers Based on Graphene Oxide–Cu(II) Complex

New highly energetic coordination polymers (ECPs), based on the graphene oxide (GO)-copper(II) complex, have been synthesized using 5,5′-azo-1,2,3,4-tetrazole (TEZ) and 4,4′-azo-1,2,4-triazole (ATRZ), as linking ligands between GO-Cu layers. The molecular structures, sensitivity, and detonation performances of these ECPs were determined. It was shown that these energetic nanomaterials are insensitive and highly thermostable, due to high heat and impact dissipation capacity of GO sheets. In particular, the GO-TEZ-Cu(II) ECP shows low sensitivity to impact and electrostatic discharge (Im = 21 J; ESD of 1995 mJ) and has a comparable detonation performance to RDX. Also, our novel GO/Cu(II)/ATRZ hybrid ECP GO-Cu(II)-ATRZ ECP exhibits high density (2.85 g·cm–3), remarkably high thermostability (Tp = 456 °C), and low sensitivity (Im > 98 J; ESD of 1000 mJ). The latter material has a calculated detonation velocity of 7082 m·s–1, which is slightly higher than that of energetic ATRZ-Cu(II) 3D MOF and higher than on...

Formation of Highly Thermostable Copper-Containing Energetic Coordination Polymers Based on Oxidized Triaminoguanidine.

A series of novel highly thermostable energetic coordination polymers (ECPs), with promising mechanical sensitivity properties, were prepared by an in situ oxidation-coordination reaction of triaminoguanidine hydrochloride with copper nitrate in aqueous solution. The molecular structures and properties of these ECPs could be tuned, by varying the ratios and concentrations of the starting materials. Our ECPs exhibit remarkable thermostability (>390 °C) and very low sensitivity to impact (Im > 98 J). The best-performing material (ECP-5) has a calculated detonation velocity of 8969 m·s(-1) and a decomposition peak temperature of 396.9 °C, demonstrating an outstanding balance between two inherently contradicting properties: high detonation performance and very low sensitivity.

Thermolysis, nonisothermal decomposition kinetics, calculated detonation velocity and safety assessment of dihydroxylammonium 5, 5′-bistetrazole-1, 1′-diolate

Thermal decomposition study of dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate (TKX-50) was investigated by using TG–DTG and TG-IR-MS and found that N2, N2O, NH3 and H2O were the main products during the decomposition process. The kinetic parameters (Ea = 138.96 kJ mol−1 and A = 1012.93 s−1) for thermal decomposition reaction of TKX-50 were obtained from DSC profile by differential method and integral method, and the nonisothermal kinetic equation of the exothermic process was $${\text{d}}\alpha /{\text{d}}T = (10^{12.93} /\beta )3(1 - \alpha )[ - \ln (1 - \alpha )]^{2/3} \exp ( - 1.6713 \times 10^{4} /T),$$ suggesting that the main exothermic decomposition reaction mechanism of TKX-50 was classified as Avrami–Erofeev equation. In addition, the theoretical detonation velocity (D = 8804 m/s) of TKX-50 at 298.15 K was calculated by a simple method. Finally, the safety parameters of TKX-50 (25 kg) including time to maximum rate under adiabatic conditions and self-accelerating decomposition temperature were calculated to be 142.12 and 129.01 °C by using AKTS software.

3,6,7-Triamino-[1,2,4]triazolo[4,3-b][1,2,4]triazole: A Non-toxic, High-Performance Energetic Building Block with Excellent Stability.

A novel strategy for the design of energetic materials that uses fused amino-substituted triazoles as energetic building blocks is presented. The 3,6,7-triamino-7H-[1,2,4]triazolo[4,3-b][1,2,4]triazolium (TATOT) motif can be incorporated into many ionic, nitrogen-rich materials to form salts with advantages such as remarkably high stability towards physical or mechanical stimuli, excellent calculated detonation velocity, and toxicity low enough to qualify them as "green explosives". Neutral TATOT can be synthesized in a convenient and inexpensive two-step protocol in high yield. To demonstrate the superior properties of TATOT, 13 ionic derivatives were synthesized and their chemical- and physicochemical properties (e.g., sensitivities towards impact, friction and electrostatic discharge) were investigated extensively. Low toxicity was demonstrated for neutral TATOT and its nitrate salt. Both are insensitive towards impact and friction and the nitrate salt combines outstanding thermal stability (decomposition temperature=280 °C) with promising calculated energetic values.

The Research of Applied Analysis Method on Shaped Charge Detonation Parameters

For avoid the perforation accident, oil perforating urgent need to calculate accurately shaped charge detonation parameters to guide the design and construction of perforation. According to the charge type and characteristics of shaped charge, based on traditional detonation theory and detonation parameters calculated method, this paper first determining shaped explosive detonation reaction equation, then analysis the shaped charge detonation heat, detonation temperature, detonation tolerance and detonation pressure and detonating velocity, extract the analytical methods of shaped charges detonation parameters suitable for oil at last. The specific practices: determined the reaction equation of shaped charges explosive with a maximum heat release rule; determined detonation heat, detonation temperature and detonation tolerance with law of Hess, internal energy value method and Avogadro law; calculated detonation velocity and pressure by Kamlet law; use engineering calculation method to analyze the detonating velocity as to the non-C-H-N-O composition shaped charges which containing feeling agent, bonding agent, flammable agent, plasticizer and other active agent; by revision Kamlet formula, get detonation pressure calculation formula.

Prediction of Detonation Velocity of Aluminized Explosive by Artificial Neural Network

In this study, a three-layer artificial neural network (ANN) model was constructed to predict the detonation velocity of aluminized explosive. Elemental composition and loading density were employed as input descriptors and detonation velocity was used as output. The dataset of 61 aluminized explosives was randomly divided into a training set (49) and a prediction set (12). After optimized by adjusting various parameters, the optimal condition of the neural network was obtained. Simulated with the final optimum neural network [812, calculated detonation velocity show good agreement with experimental results. It is shown that ANN is able to produce accurate predictions of the detonation velocity of aluminized explosive.

Quantum chemical studies on the aminopolynitropyrazoles

We have explored the geometric and electronic structures, band gap, thermodynamic properties, density, detonation velocity and detonation pressure of aminopolynitropyrazoles using the density functional theory (DFT) at the B3LYP/aug-cc-pVDZ level. The calculated detonation velocity and detonation pressure, stability and sensitivity of model compounds appear to be promising compared to the known explosives 3,4-dinitro-1 H-pyrazole (3,4-DNP), 3,5-dinitro-1 H-pyrazole (3,5-DNP), hexahydro-1,3,5-trinitro-1,3,5-triazinane (RDX) and octahydro-1,3,5,7-tetranitro-l,3,5,7-tetraazocane (HMX). The position of NH(2) group in the polynitropyrazoles presumably determines the structure, stability, sensitivity, density, detonation velocity and detonation pressure.

Synthesis, single crystal structure and characterization of pentanitromonoformylhexaazaisowurtzitane

Pentanitromonoformylhexaazaisowurtzitane (PNMFIW) was synthesized by the nitrolysis of tetraacetyldiformylhexaazaisowurtzitane (TADFIW) in mixed nitric and sulfuric acids and structurally characterized by element analysis, FT-IR, MS and 1H NMR. Single crystals of PNMFIW were grown from aqueous solution employing the technique of controlled evaporation. PNMFIW belongs to the orthorhombic system having four molecules in the unit cell, with space group P2(1)2(1)2(1) and the lattice parameters a = 8.8000(18) Å, b = 12.534(2) Å, and c = 12.829(3) Å. The calculated density reaches 1.977 g/cm 3 at 93 K, while the experimental density is 1.946 g/cm 3 at 20 °C. The calculated detonation velocity and pressure of PNMFIW according to the experimental density are 9195.76 m/s and 39.68 GPa, respectively. PNMFIW is insensitive compared with ɛ-HNIW through drop hammer impact sensitivity test.

An Ab Initio Theoretical Study of 2,4,6‐Trinitro‐1,3,5‐Triazine, 3,6‐Dinitro‐1,2,4,5‐Tetrazine, and 2,5,8‐Trinitro‐Tri‐s‐Triazine

AbstractIn order to evaluate 2,4,6‐trinitro‐1,3,5‐triazine (TNTAz), 3,6‐dinitro‐1,2,4,5‐tetrazine (DNTAz), and 2,5,8‐trinitro‐tri‐s‐triazine (TNTsTAz), the geometries of these compounds have been fully optimized employing the B3LYP density functional method and the AUG‐cc‐pVDZ basis set. The accurate gas phase enthalpies of formation have been obtained by using the atomization procedure and designing isodesmic reactions in which the parent rings are not destroyed. Based on B3LYP/AUG‐cc‐pVDZ calculated geometries and natural charges, the crystal structures have been predicted using the Karfunkel–Gdanitz method. Computed results show that there exists extended conjugation over the parent rings of these compounds. More energy content is reserved in DNTAz than in both TNTAz and TNTsTAz. The title compounds are much more sensitive than 1,3,5‐trinitrobenzene. The calculated detonation velocity of DNTAz reaches 9.73–9.88 km s−1, being larger than those of CL‐20 and TNTAz. TNTsTAz has no advantage over the widely used energetic compounds such as RDX and HMX.

A Novel Insensitive High Explosive 3,4‐Bis (Aminofurazano) Furoxan

AbstractA novel insensitive high explosive 3,4‐bis (aminofurazano) furoxan (BAFF) was prepared using 3‐amino‐4‐acylchloroximinofurazan (ACOF) as a precursor. The molecular and crystal structures of BAFF were characterized by IR, MS, 1H NMR, 13C NMR, elemental analysis, and single crystal X‐ray diffraction. The single crystal structure of BAFF recrystallized from water is monoclinic, space group P 21/c, and ρc=1.745 g cm−3, and that recrystallized from ethanol is triclinic, space group P 1, and ρc=1.737 g cm−3. BAFF has multiple crystal forms. The calculated detonation velocity by BKW code is 8100 m s−1 (ρ=1.795 g cm−3, theoretical density calculated by quantum chemistry) and the experimental value is 7177 m s−1 (ρ=1.530 g cm−3, charge density). The tested values of impact, friction, and electrostatic spark sensitivity show that BAFF is insensitive.

Calculation of the Energy of Explosives with a Partial Reaction Model. Comparison with Cylinder Test Data

AbstractThe energy delivered by explosives is described by means of the useful expansion work along the isentrope of the detonation products. A thermodynamic code (W‐DETCOM) is used, in which a partial reaction model has been implemented. In this model, the reacted fraction of the explosive in the detonation state is used as a fitting factor so that the calculated detonation velocity meets the experimental value. Calculations based on such a model have been carried out for a number of commercial explosives of ANFO and emulsion types. The BKW (Becker‐Kistiakowsky‐Wilson) equation of state is used for the detonation gases with the Sandia parameter set (BKWS). The energy delivered in the expansion (useful work) is calculated, and the values obtained are compared with the Gurney energies from cylinder test data at various expansion ratios. The expansion work values obtained are much more realistic than those from an ideal detonation calculation and, in most cases, the values predicted by the calculation are in good agreement with the experimental ones.

N-Nitroso- and N-Nitraminotetrazoles

N-Nitroso- (5a,c) and N-nitraminotetrazoles (6a-c) were synthesized from the corresponding aminotetrazoles (3a-c) either by the direct nitration with acetic anhydride/HNO3 or by dehydration of the corresponding nitrates (4a-c) with concentrated sulfuric acid. The conversion of the N-nitrosoaminotetrazoles (5a,c) with peroxytrifluoroacetic acid (CF3CO3H) yielded the corresponding nitramines in high yield (6a (82%), 6c (80%)). The N-nitroso- (5a,c) and N-nitraminotetrazoles (6a-c) have been fully characterized by vibrational (IR, Raman) and multinuclear NMR spectroscopy (14N/15N, 1H, 13C), mass spectrometry, and elemental analysis. A detailed discussion of the 15N chemical shifts and 1H-15N coupling constants is given. The molecular structures in the solid state were determined by single-crystal X-ray diffraction (3a,c; 5a,c; 6a-c) and a detailed discussion of the molecular structures will be presented. Furthermore, the structure and bonding as well as N,N rotational barriers are discussed on the basis of theoretically obtained data (B3LYP/6-31G(d,p), NBO analysis). In the case of two N-nitraminotetrazoles (6a,c) the physicochemical properties (e.g., D, P, delta(f)H degrees) were evaluated. The heat of formation was calculated to be positive for 6a and 6c (+2.8 and +85.2 kcal mol(-1), respectively) and the calculated detonation velocity with 5988 (6a) and 7181 (6c) m s(-1) reaches values of TNT and nitroglycerin.

Analytic Model of Reactive Flow

A simple analytic model allows prediction of rate constants and size effect behavior before a hydrocode run, if size effect data exist. It utilizes detonation velocity, average detonation rate, pressure and energy at infinite radius. This allows the derivation of a generalized radius, which becomes larger as the explosive becomes more non-ideal. The model is applied to near-ideal PBX 9404, in-between ANFO and most non-ideal AN. The power of the pressure declines from 2.3, and 1.5 to 0.8 across this set. The power of the burn fraction, F, is 0.8, 0 and 0, so that an F-term is important only for the ideal explosives. The size effect shapes change from concave-down to nearly straight to concave-up. Failure is associated with ideal explosives when the calculated detonation velocity turns in a double-valued way. The effect of the power of the pressure may be simulated by including a pressure cut-off in the detonation rate. The model allows comparison of a wide spectrum of explosives providing that a single detonation rate is feasible.

3-Nitro-1,2,4-triazol-5-one, a less sensitive explosive

A less sensitive explosive, 3-nitro-1,2,4-triazol-5-one. The compound 3-nitro-1,2,4-triazol-5-one (NTO) has a crystal density of 1.93 g/cm 3 and calculated detonation velocity and pressure equivalent to those of RDX. It can be prepared in high yield from inexpensive starting materials in a safe synthesis. Results from initial small-scale sensitivity tests indicate that NTO is less sensitive than RDX and HMX in all respects. A 4.13 cm diameter, unconfined plate-dent test at 92% of crystal density gave the detonation pressure predicted for NTO by the BKW calculation.

Predicting High Explosive Detonation Velocities from their composition and structure (II)

AbstractAn earlier paper(1) described a simple linear relationship between detonation velocity of 64 ideal C,H,N,O type explosives at their theoretical maximum densities (TMD's) and a factor. F, that is dependent solely upon chemical composition and structure. Based upon available experimental data for nine fluorine‐containing explosives, the equation for calculating the factor has been expanded to include compositional terms for fluorinated compounds. In addition, the reliability of the linear relationship has been further tested against seven more recently published C,H,N,O type explosive experimental detonation velocity data points. The calculated detonation velocity values for all 16 explosives lie within 6.0% of experimental with an absolute error of ± 3.0%.

Predicting High Explosive Detonation Velocities from their composition and structure

AbstractA simple, empirical linear relationship between detonation velocity at theoretical maximum density and a factor, F, that is dependent solely upon chemical composition and structure is postulated for a gamut of ideal explosives. The explosives ranged from nitroaromatics, cyclic and linear nitramines, nitrate esters and nitro‐nitrato aliphatics to zero hydrogen explosives, carbonless explosives and hydrogen rich explosives. Of the 64 explosives evaluated, 95% had calculated detonation velocity values within 5% of experimental and 98% within 7%. Only nitromethan varied grossly (−; 13%) from calculated velocity and the absolute error for all explosives is ±2.3%.

Slowdown of oxyhydrogen detonation by surface catalysis

The propagation velocities of stoichiometric oxyhydrogen detonations were measured in thin tubes of different wall materials. From 4 to 6% velocity differences were observed consistently for pyrex and γ-alumina walls. By changing the tube geometries, it was confirmed that this velocity difference can be explained only by the catalysis of the wall material. To elucidate this result, one-dimensional gasdynamic analysis was performed, including various possible wall reactions. The solutions of this eigenvalue problem gave the relation of each reaction and its catalytic efficiency to the calculated detonation velocity. The results showed that the observed velocity difference can be explained only if we assume that H+OH→H 2 O or H→1/2 H 2 occurs with the maximum catalytic efficiency, i.e., unity. After some speculations, H+OH→ H 2 O was considered more probable, the catalytic efficiency of γ-alumina being nearly unit for this reaction at 300 K.