Computed Thermodynamic and Explosive Properties of 1‐Azido‐2‐nitro‐2‐azapropane (ANAP)

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 Δ_fH°, ANAP(l)=+297.1 kJ mol⁻¹. The heat of detonation (Q_v), the detonation pressure (P), and the detonation velocity of ANAP were calculated to be Q_v=−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: Q_v=−6848 kJ kg⁻¹, P=27.0 GPa, D=8284 m s⁻¹.     

A DFT Study on the Structures and Energies of Isomers of 4‐Amino‐1,3‐dinitro‐1,2,4‐triazol‐5‐one‐2‐oxide: New High Energy Density Compounds

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.     

Hydrostatic Compression Curve for Triamino‐Trinitrobenzene Determined to 13.0 GPa with Powder X‐Ray Diffraction

Using powder X‐ray diffraction in conjunction with a diamond anvil cell (DAC), the unit cell volume of triamino‐trinitrobenzene (TATB) has been measured from ambient pressure to 13 GPa. The resultant isotherm is compared with previous theoretical (Byrd and Rice and Pastine and Bernecker) and experimental (Olinger and Cady) works. While all reports are consistent to approximately 2 GPa, our measurements reveal a slightly stiffer TATB material than reported by Olinger and Cady and an intermediate compressibility compared with the isotherms predicted by the two theoretical works. Analysis of the room temperature isotherm using the semi‐empirical, Murnaghan, Birch–Murnaghan, and Vinet equations of state (EOS) provided a determination of the isothermal bulk modulus (K_o) and its pressure‐derivative (K_o′) for TATB. From these fits to our P–V isotherm, from ambient pressure to 8 GPa, the average results for the zero‐pressure bulk modulus and its pressure derivative were found to be 14.7 GPa and 10.1, respectively. For comparison to shock experiments on pressed TATB powder and its plastic‐bonded formulation PBX 9502 (95% TATB, 5% Kel‐F 800), the isotherm was transformed to the pseudo‐velocity U_s–u_p plane using the Rankine–Hugoniot jump conditions. This analysis provides an extrapolated bulk sound speed, c_o=1.70 km s⁻¹, for TATB and its agreement with a previous determination (c_o=1.43 km s⁻¹) is discussed. Furthermore, our P–V and corresponding U_s–u_p curves reveal a subtle cusp at approximately 8 GPa. This cusp is discussed in relation to similar observations made for the aromatic hydrocarbons anthracene, benzene and toluene, graphite, and trinitrotoluene (TNT).     

Highly Active and Enantioselective Rhodium‐Catalyzed Asymmetric 1,4‐Addition of Arylboronic Acid to α,β‐ Unsaturated Ketone by using Electron‐Poor MeO‐F12‐BIPHEP

The asymmetric 1,4‐addition of phenylboronic acid to cyclohexenone were performed by using a low amount of rhodium/(R)‐(6,6′‐dimethoxybiphenyl‐2,2′‐diyl)bis[bis(3,4,5‐trifluorophenyl)phosphine] (MeO‐F₁₂‐BIPHEP) catalyst. Because the catalyst shows thermal resistance at 100 °C, up to 0.00025 mol% Rh catalyst showed good catalytic activity. The highest turnover frequency (TOF) and turnover number (TON) observed were 53,000 h⁻¹ and 320,000, respectively. The enantioselectivities of the products were maintained at a high level of 98% ee in these reactions. The Eyring plots gave the following kinetic parameters (ΔΔH^≠=−4.0±0.1 kcal mol⁻¹ and ΔΔS^≠=−1.3±0.3 cal mol⁻¹ K⁻¹), indicating that the entropy contribution is relatively small. Both the result and consideration of the transition state in the insertion step at the B3LYP/6‐31G(d) [LANL2DZ for rhodium] levels indicated that the less σ‐donating electron‐poor (R)‐MeO‐F₁₂‐BIPHEP could be creating a rigid chiral environment around the rhodium catalyst even at high temperature.     

4,5‐Bis(5‐tetrazolyl)‐1,2,3‐triazole: Synthesis and Performance

4,5‐Bis(5‐tetrazolyl)‐1,2,3‐triazole (BTT) was synthesized by a new method. Its structure was characterized by IR and ¹³C NMR spectroscopy and elemental analysis (EA). The thermal stability of BTT was investigated by TG‐DSC technique. The kinetic parameters including activation energy and pro‐exponential factor were calculated by Kissinger equation. The combustion heat, detonation products, hygroscopicity, impact, and friction sensitivity were also measured. The formation heat, detonation pressure, and detonation velocity of BTT were calculated. BTT has high detonation pressure and detonation velocity (P=35.36 GPa, D=8.971 km s⁻¹). BTT has potential application prospect as environmentally friendly gas generant, insensitive explosive and solid propellant.     

Non‐Isothermal Decomposition Kinetics,Heat Capacity,and Thermal Safety of 2‐Nitroimino‐5‐Nitro‐Hexahydro‐1,3,5‐Triazine (NNHT)

The kinetic equation describing the thermal decomposition reaction of NNHT obtained by TG‐DTG data, integral isoconversional non‐linear method and integral method of treating TG‐DTG curves is . The specific heat capacity (C_p) of NNHT was determined with the continuous C_p mode of the microcalorimeter. The equation of C_p (T) was obtained. The standard molar heat capacity of NNHT was 218.41 J mol⁻¹ K⁻¹ at 298.15 K. With the help of the onset temperature (T_e) and maximum peak temperature (T_p) from the non‐isothermal DTG curves of NNHT at different heating rates (β), the apparent activation energy (E_K and E_O), and the pre‐exponential constant (A_K) of the thermal decomposition reaction obtained by Kissinger’s method and Ozawa’s method, C_p obtained by microcalorimetry, density (ρ) and thermal conductivity (λ), the decomposition heat (Q_d, taking half‐explosion heat), Zhang‐Hu‐Xie‐Li’s formula, Smith’s equation, Friedman’s formula, Bruckman‐Guillet’s formula, and Wang‐Du’s formulas, the values (T_e0 and T_p0) of T_e and T_p corresponding to β→0, thermal explosion temperature (T_be and T_bp), adiabatic time‐to‐explosion (t_TIad), 50 % drop height (H₅₀) of impact sensitivity, critical temperature of hot‐spot initiation (T_cr), thermal sensitivity probability density function [S(T)] versus temperature (T) relation curves for spheroidic NNHT with radius of 1 m surrounded with ambient temperature of 300 K, peak temperature corresponding to the maximum value of S(T) versus T relation curve ( ), safety degree (SD), and critical ambient temperature(T_acr) of thermal explosion of NNHT are calculated. The following results of evaluating the thermal safety of NNHT are obtained: T_SADT=T_e0=453.34 K, T_SADT=T_p0=454.86 K, T_be=462.68 K, T_bp=467.22 K, t_TIad=1.03 s, H₅₀=17.69 cm, T_α=461.4 K. SD=72.74 %, P_TE=27.26 %, and T_acr=321.96 K.     

Synthesis and Characterization of 1,5‐Dinitro‐2,6‐bis(trinitromethyl)‐3a,4a,7a,8a‐tetrahydro‐[1,4]dioxino[2,3‐d:5,6‐d′]diimidazole (DNTNDI)

The polynitro imidazole derivative 1,5‐dinitro‐2,6‐bis(trinitromethyl)‐3a,4a,7a,8a‐tetrahydro‐[1,4]dioxino[2,3‐d:5,6‐d′]diimidazole (DNTNDI) was synthesized through nitration of 2‐(dinitromethylene)‐1H‐imidazol‐4‐ol in HNO₃/Ac₂O followed by cyclization of the di‐enol. It was characterized by NMR, IR, elemental analysis, and single‐crystal X‐ray diffraction analysis. Compound DNTNDI crystallizes in the orthorhombic space group P2(1)2(1)2(1). The thermal decomposition was studied with thermogravimetry/derivative thermogravimetry (TG/DTG) in a nitrogen atmosphere with a heating rate of 5 K min⁻¹. The TG/DTG analysis indicated that DNTNDI has 97.64 % mass loss between 127 °C and 173 °C by undergoing exothermic decomposition. The density of DNTNDI was determined as 1.906 g cm⁻³ at 293 K with an Ultrapycno 1000 Pycnometer. The denotation velocity and denotation pressure of DNTNDI were calculated as 9325 m s⁻¹ and 40 GPa by applying the LOTUSES (version 1.4) code, respectively. The oxygen balance of DNTNDI is 0 and its oxygen content amounts to 51.78 %, which is superior to that of new generation of chlorine‐free oxidizer ammonium dinitramide (ADN).     

The β‐δ‐Phase Transition and Thermal Expansion of Octahydro‐1,3,5,7‐Tetranitro‐1,3,5,7‐Tetrazocine

Phase behavior of octahydro‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine (HMX) is investigated by X‐ray powder diffraction (XRD). The XRD patterns at elevated temperature show that there is a co‐existing temperature range of β‐ and δ‐phase during the phase transition process. Additionally, mechanical forces can catalyze the conversion from δ‐ back to β‐phase. Based on the diffraction patterns of β‐ and δ‐phase at different temperatures, we calculate the coefficients of thermal expansion by Rietveld refinement. For β‐HMX, the linear coefficients of thermal expansion of a‐axis and b‐axis are about 1.37×10⁻⁵ and 1.25×10⁻⁴ °C⁻¹. A slight decrease in c‐axis with temperature is also observed, and the value is about −0.63×10⁻⁵ °C⁻¹. The volume coefficient of thermal expansion is about 1.60×10⁻⁴ °C⁻¹, with a 2.2% change from 30 to 170 °C. For δ‐HMX, the linear coefficients of thermal expansion of a‐axis and c‐axis are found to be 5.39×10⁻⁵ and 2.38×10⁻⁵ °C⁻¹, respectively. The volume coefficient of thermal expansion is about 1.33×10⁻⁴ °C⁻¹, with a 2.6% change from 30 to 230 °C. The results indicate that β‐HMX has a similar volume coefficient of thermal expansion compared with δ‐HMX, and there is about 10.5% expansion from β‐HMX at 30 °C to δ‐HMX at 230 °C, of which about 7% may be attributed to the reconstructive transition.     

Improved Synthesis and X‐Ray Structure of 5‐Aminotetrazolium Nitrate

5‐Aminotetrazolium nitrate was synthesized in high yield and characterized using Raman and multinuclear NMR spectroscopy (¹H, ¹³C, ¹⁵N). The molecular structure of 5‐aminotetrazolium nitrate in the crystalline state was determined by X‐ray crystallography: monoclinic, P 2₁/c, a=1.05493(8) nm, b=0.34556(4) nm, c=1.4606(1) nm, β=90.548(9)°, V=0.53244(8) nm³, Z=4, ϱ=1.847 g cm⁻³, R₁=0.034, wR₂ (all data)=0.090. The thermal stability of 5‐aminotetrazolium nitrate was determined using differential scanning calorimetry; the compound decomposes at 167 °C. The enthalpy of combustion (Δ_combH) of 5‐aminotetrazolium nitrate ([CH₄N₅]⁺[NO₃]⁻) was determined experimentally using oxygen bomb calorimetry: Δ_combH([CH₄N₅]⁺[NO₃]⁻)=−6020±200 kJ kg⁻¹. The standard enthalpy of formation (Δ_fH°) of [CH₄N₅]⁺[NO₃]⁻ was obtained on the basis of quantum chemical computations at the electron‐correlated ab initio MP2 (second order Møller‐Plesset perturbation theory) level of theory using a correlation consistent double‐zeta basis set (cc‐pVTZ): Δ_fH°([CH₄N₅]⁺[NO₃]⁻(s))=+87 kJ mol⁻¹=+586 kJ kg⁻¹. The detonation velocity (D) and the detonation pressure (P) of 5‐aminotetrazolium nitrate were calculated using the empirical equations by Kamlet and Jacobs: D([CH₄N₅]⁺[NO₃]⁻)=8.90 mm μs⁻¹ and P([CH₄N₅]⁺[NO₃]⁻)=35.7 GPa.     

The Facile Synthesis and Energetic Properties of an Energetic Furoxan Lacking Traditional “Explosophore” Moieties: (E,E)‐3,4‐bis(oximomethyl)furoxan (DPX1)

Energetic furoxan (E,E)‐3,4‐bis(oximomethyl)furoxan (DPX1) was synthesized in 75 % yield, using a literature procedure, from a precursor readily available in one step from nitromethane. DPX1 was characterized for the first time as an energetic material in terms of calculated performance (V_det = 8245 m s⁻¹; p_C‐J = 29.0 GPa) and measured sensitivity (impact: 10 J; friction: 192 N; T_dec: 168 °C). DPX1 exhibits a sensitivity less than that of RDX, and a performance significantly higher than 2,4,6‐trinitrotoluene (TNT).     

Phenoxaphosphino‐Modified Xantphos‐Type Ligands in the Rhodium‐Catalysed Hydroformylation of Internal and Terminal Alkenes

The solubility of the modifying ligand is an important parameter for the efficiency of a rhodium‐catalysed hydroformylation system. A facile synthetic procedure for the preparation of well‐defined xanthene‐type ligands was developed in order to study the influence of alkyl substituents at the 2‐, and 7‐positions of the 9,9‐dimethylxanthene backbone and at the 2‐, and 8‐positions of the phenoxaphosphino moiety of ligands 1 – 16 on solubility in toluene and the influence of these substituents on the performance of the ligands in the rhodium‐catalysed hydroformylation. An increase in solubility from 2.3 mmol⋅L⁻¹ to >495 mmol⋅L⁻¹ was observed from the least soluble to the most soluble ligand. A solubility of at least 58 mmol⋅L⁻¹ was estimated to be sufficient for a large‐scale application of these ligands in hydroformylation. Highly active and selective catalysts for the rhodium‐catalysed hydroformylation of 1‐octene and trans‐2‐octene to nonanal, and for the hydroformylation of 2‐pentene to hexanal were obtained by employing these ligands. Average rates of >1600 (mol aldehyde) × (mol Rh)⁻¹×h⁻¹ {conditions: p(CO/H₂) = 20 bar, T = 353 K, [Rh] = 1 mM, [alkene] = 637 mM} and excellent regio‐selectivities of up to 99% toward the linear product were obtained when 1‐octene was used as substrate. For internal olefins average rates of >145 (mol aldehyde)×(mol Rh)⁻¹×h⁻¹ {p(CO/H₂) = 3.6–10 bar, T = 393 K, [Rh] = 1 mM, [alkene] = 640–928 mM} and high regio‐selectivities up to 91% toward the linear product were obtained.     

Semiconductive poly[N1,N4‐bis(thiophen‐2‐ylmethylene)benzene‐1,4‐diamine]‐nickel oxide nanocomposite based ethanol sensor

This study aims to use the conductivity of a synthetic polymer as the sensing probe for ethanol. In order to enhance the sensitivity of the sensor, a composite of the polymer and nickel oxide (NiO) nanoparticles was formed as it improved the conductivity. This composite exhibited 100 times more conductivity than the neat polymer. The semiconductive nanocomposite of poly [N¹,N⁴‐bis(thiophen‐2‐ylmethylene)benzene‐1,4‐diamine]‐nickel oxide (PBTMBDA‐NiO) was prepared by in situ chemical oxidative polymerization. The monomer was N¹,N⁴‐bis(thiophen‐2‐ylmethylene)benzene‐1,4‐diamine (BTMBDA). The monomer (BTMBDA), polymer (PBTMBDA), and NiO nanoparticles used in this study were synthesized. The monomer was prepared by refluxing together 2‐thiophene carboxaldehyde, benzene‐1,4‐diamine, and few drops of glacial acetic acid in ethanol medium for 3 h. The polymer, PBTMBDA, was formed by the chemical oxidative polymerization of BTMBDA in chloroform by FeCl₃. NiO nanoparticles were prepared by slow addition of aqueous ammonia to anhydrous nickel chloride at room temperature (28 ± 2 °C), and at a pH of 8 under constant stirring condition. The composite was formed by in situ chemical oxidative polymerization of BTMBDA in chloroform by FeCl₃ in the presence of the dispersed NiO nanoparticles. The molecular structure of BTMBDA and PBTMBDA were confirmed by nuclear magnetic resonance (NMR) (¹H, ¹³C, and Dept‐90°), Fourier transform infrared spectroscopy, and ultraviolet (UV)–visible spectroscopy. The PBTMBDA and PBTMBDA‐NiO nanocomposite were characterized by X‐ray diffraction, thermogravimetric analysis, field emission scanning electron microscopy, and energy‐dispersive X‐ray spectroscopy analysis. The results of characterization studies indicate the strong interaction between PBTMBDA and NiO in the nanocomposite. The broadness of ¹H NMR peaks in PBTMBDA was due to the increased number of monomer units. The disappearance of the peak of α‐hydrogens on thiophene confirms the polymerization involving the fifth position of thiophene part of BTMBDA. The Fourier transform infrared spectroscopy spectra revealed that position of the characteristic peaks of the functional groups in the monomer shifted toward lower wave numbers in PBTMBDA and PBTMBDA‐NiO nanocomposite. This shifting confirms the presence of extended conjugation along the polymer backbone. Electronic spectra of these compounds showed three absorption bands corresponding to π→π*, n→π* and n→π* transitions of π electron of carbon, lone pair electrons of S, and lone pair electrons of N (imine) groups, respectively. From the Tafel plot, the exchange current density evaluated for the BTMBDA and PBTMBDA are 0.2815 × 10⁻⁸ and 1.1508 × 10⁻⁸ A cm⁻², respectively. PBTMBDA is evaluated to be a better electrode material than the BTMBDA. The X‐ray diffraction plots showed that the characteristic peak of NiO in PBTMBDA‐NiO nanocomposite suggested successful incorporation of NiO in PBTMBDA‐NiO nanocomposite. The thermogravimetric analysis revealed the improved thermal stability of the composite. Field emission scanning electron microscopy and energy‐dispersive X‐ray spectroscopy analysis confirmed the presence of the NiO in the composite. Incorporation of nickel oxide nanoparticles improved the electrical conductivity and stability of PBTMBDA. The conductivity of the polymer was found to be of the order of 10⁻⁵ S cm⁻¹ while that of the composite was of the order of 10⁻³ S cm⁻¹. The nanocomposite was found to be thermally more stable than PBTMBDA and exhibited better direct‐current electrical conductivity and isothermal stability than the PBTMBDA as revealed by the four‐probe study. The electrical conductivity as inferred from the four‐probe method was used as the parameter to study the isothermal stability of the composite. The PBTMBDA‐NiO nanocomposite based vapor sensor was constructed for the sensing of ethanol vapor in commercial ethanol and real samples (alcoholic drinks: Beer, Wine, Brandy, Vodka, Whisky, and Rum) It was observed that on exposure to ethanol vapor at ambient temperature, the electrical resistivity of the nanocomposite increased indicating suppression of charge carriers. The interaction of ethanol vapor with PBTMBDA in PBTMBDA‐NiO nanocomposite was confirmed by IR spectral technique. The change in the structure of the PBTMBDA on interaction with ethanol was highlighted by the changes in the infrared spectrum. The conductivity of the polymer was explained using the structure‐activity relationship of the monomer evaluated using Gaussian 09 software. This study also analyzed the total electron density with electrostatic potential of the monomer and its correlation with chemical reactivity in order to explain the ethanol vapor sensing‐property of the nanocomposite. A new method of ethanol vapor sensing by a conducting polymer composite is hereby reported. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45918.     

γ‐FOX‐7: Structure of a High Energy Density Material Immediately Prior to Decomposition

1,1‐Diamino‐2,2‐dinitroethene, C₂H₄N₄O₄ (FOX‐7), is a novel high energy density material with low friction and impact sensitivity and a high activation barrier to detonation. In this study, the previously unknown crystal structure of the γ‐polymorph of trimorphic FOX‐7 is reported. γ‐FOX‐7 is stable from ∼435 K until the compound decomposes just above 504 K. A single crystal of α‐FOX‐7 (P2₁/n, Z=4, a=694.67(7) pm, b=668.87(9) pm, c=1135.1(1) pm, β=90.14(1)°, T=373 K) was first transformed into a single crystal of β‐FOX‐7 (P2₁2₁2₁, Z=4, a=698.6(1) pm, b=668.6(2) pm, c=1168.7(3) pm, T=423 K) and then into a single crystal of γ‐FOX‐7 at 450 K. The γ‐FOX‐7 crystal was then subsequently quenched to 200 K. The structure of γ‐FOX‐7 (P2₁/n, Z=8, a=1335.4(3) pm, b=689.5(1) pm, c=1205.0(2) pm, β=111.102(8)°, T=200 K) consists of four planar layers, each containing two crystallographically independent FOX‐7 molecules found in the asymmetric unit.     

Characterization of 4,6‐Diazido‐N‐nitro‐1,3,5‐triazine‐2‐amine

4,6‐Diazido‐N‐nitro‐1,3,5‐triazine‐2‐amine (DANT) was prepared with a 35 % yield from cyanuric chloride in a three step process. DANT was characterized by IR and NMR spectroscopy (¹H, ¹³C, ¹⁵N), single‐crystal X‐ray diffraction, and DTA. The crystal density of DANT is 1.849 g cm⁻³. The cyclization of one azido group and one nitrogen atom of the triazine group giving tetrazole was observed for DANT in a dimethyl sulfoxide solution using NMR spectroscopy. An equilibrium exists between the original DANT molecule and its cyclic form at a ratio of 7 : 3. The sensitivity of DANT to impact is between that for PETN and RDX, sensitivity to friction is between that for lead azide and PETN, and sensitivity to electric discharge is about the same as for PETN. DANT′s heat of combustion is 2060 kJ mol⁻¹.     

Synthesis,Crystal Structure,and Thermal Behavior of 3‐(4‐Aminofurazan‐3‐yl)‐4‐(4‐nitrofurazan‐3‐yl)furazan (ANTF)

The energetic material 3‐(4‐aminofurazan‐3‐yl)‐4‐(4‐nitrofurazan‐3‐yl)furazan (ANTF) with low melting‐point was synthesized by means of an improved oxidation reaction from 3,4‐bis(4′‐aminofurazano‐3′‐yl)furazan. The structure of ANTF was confirmed by ¹³C NMR spectroscopy, mass spectrometry, and the crystal structure was determined by X‐ray diffraction. ANTF crystallized in monoclinic system P2₁/c, with a crystal density of 1.785 g cm⁻³ and crystal parameters a=6.6226(9) Å, b=26.294(2) Å, c=6.5394(8) Å, β=119.545(17)°, V=0.9907(2) nm³, Z=4, μ=0.157 mm⁻¹, F(000)=536. The thermal stability and non‐isothermal kinetics of ANTF were studied by differential scanning calorimetry (DSC) with heating rates of 2.5, 5, 10, and 20 K min⁻¹. The apparent activation energy (E_a) of ANTF calculated by Kissinger's equation and Ozawa's equation were 115.9 kJ mol⁻¹ and 112.6 kJ mol⁻¹, respectively, with the pre‐exponential factor lnA=21.7 s⁻¹. ANTF is a potential candidate for the melt‐cast explosive with good thermal stability and detonation performance.     

CuO‐added KNbO3‐BaZrO3 lead‐free piezoelectric ceramics with low loss and large electric field‐induced strain

CuO‐added (1‐x)KNbO₃‐x mol%BaZrO₃ ceramics with 0.0≤x≤7.0 were sintered at 960°C. Large double polarization vs electric field (P‐E) and sprout‐shaped strain vs electric field (S‐E) hysteresis curves were obtained from the specimens with x≤2.0. They exhibited large polarizing electric fields (E_P) owing to the presence of a large number of defect dipoles (P_Ds) that formed between Cu²⁺ ions and oxygen vacancies. Small double P‐E hysteresis curves were observed for the specimens with x≥3.0 with reduced E_P because of the decreased number of P_Ds and the presence of a polymorphic phase structure containing both orthorhombic and pseudocubic structures. In particular, the specimen with x=5.0 exhibited a large strain of 0.16% at 8.0 kV/mm with a small E_P of 1.2 kV/mm and good fatigue property: this specimen maintained a strain of 0.13% at 6.0 kV/mm after 10⁶ cycles of 3.0 kV/mm.     

Synthesis and Electrochemical Properties of BaFe1−xCuxO3−δ Perovskite Oxide for IT‐SOFC Cathode

A series of iron‐based perovskite oxides BaFe_1−xCu_xO_3−δ (x = 0.10, 0.15, 0.20 and 0.25, abbreviated as BFC‐10, BFC‐15, BFC‐20 and BFC‐25, respectively) as cathode materials have been prepared via a combined EDTA‐citrate complexing sol‐gel method. The effects of Cu contents on the crystal structure, chemical stability, electrical conductivity, thermal expansion coefficient (TEC) and electrochemical properties of BFC‐x materials have been studied. All the BFC‐x samples exhibit the cubic phase with a space group Pm3m (221). The electrical conductivity decreases with increasing Cu content. The maximum electrical conductivity is 60.9 ± 0.9 S cm⁻¹ for BFC‐20 at 600 °C. Substitution of Fe by Cu increases the thermal expansion coefficient. The average TEC increases from 20.6 × 10⁻⁶ K⁻¹ for BFC‐10 to 23.7 × 10⁻⁶ K⁻¹ for BFC‐25 at the temperature range of 30–850 °C. Among the samples, BFC‐20 shows the best electrochemical performance. The area specific resistance (ASR) of BFC‐20 on SDC electrolyte is 0.014 Ω cm² at 800 °C. The single fuel cell with the configguration of BFC‐20/SDC/NiO‐SDC delivers the highest power density of 0.57 W cm⁻² at 800 °C. The favorable electrochemical activities can be attributed to the cubic lattice structure and the high oxygen vacancy concentration caused by Cu doping.     

The Synthesis and Energetic Properties of 5,7‐Dinitrobenzo‐1,2,3,4‐tetrazine‐1,3‐dioxide (DNBTDO)

Energetic tetrazine‐1,3‐dioxide, 5,7‐dinitrobenzo‐1,2,3,4‐tetrazine‐1,3‐dioxide ( DNBTDO ), was synthesized in 45 % yield. DNBTDO was characterized as an energetic material in terms of performance (V_det 8411 m s⁻¹; p_{C J} 3.3×10¹⁰ Pa at a density of 1.868 g cm⁻³), mechanical sensitivity (impact and friction as a function of grain size), and thermal stability (T_dec 204 °C). DNBTDO exhibits a sensitivity slightly higher than that of RDX , and a performance slightly lower (96 % of RDX ).     

Synthesis and characterization of homo‐ and copolymers of 3‐(2‐cyano ethoxy)methyl‐ and 3‐[methoxy(triethylenoxy)]methyl‐3′‐methyl‐oxetane

Two oxetane‐derived monomers 3‐(2‐cyanoethoxy)methyl‐ and 3‐(methoxy(triethylenoxy)) methyl‐3′‐methyloxetane were prepared from the reaction of 3‐methyl‐3′‐hydroxymethyloxetane with acrylonitrile and triethylene glycol monomethyl ether, respectively. Their homo‐ and copolyethers were synthesized with BF₃· Et₂O/1,4‐butanediol and trifluoromethane sulfonic acid as initiator through cationic ring‐opening polymerization. The structure of the polymers was characterized by FTIR and¹H NMR. The ratio of two repeating units incorporated into the copolymers is well consistent with the feed ratio. Regarding glass transition temperature (T_g), the DSC data imply that the resulting copolymers have a lower T_g than pure poly(ethylene oxide). Moreover, the TGA measurements reveal that they possess in general a high heat decomposition temperature. The ion conductivity of a sample (P‐AN 20) is 1.07 × 10^?5 S cm^?1 at room temperature and 2.79 × 10^?4 S cm^?1 at 80 °C, thus presenting the potential to meet the practical requirement of lithium ion batteries for polymer electrolytes. Copyright © 2005 Society of Chemical Industry     

Synthesis,Crystal Structure,and Thermal Behaviors of 3‐Nitro‐1,5‐bis(4,4′‐dimethylazide)‐1,2,3‐triazolyl‐3‐azapentane (NDTAP)

The energetic material, 3‐nitro‐1,5‐bis(4,4′‐dimethyl azide)‐1,2,3‐triazolyl‐3‐azapentane (NDTAP), was firstly synthesized by means of Click Chemistry using 1,5‐diazido‐3‐nitrazapentane as main material. The structure of NDTAP was confirmed by IR, ¹H NMR, and ¹³C NMR spectroscopy; mass spectrometry, and elemental analysis. The crystal structure of NDTAP was determined by X‐ray diffraction. It belongs to monoclinic system, space group C2/c with crystal parameters a=1.7285(8) nm, b=0.6061(3) nm, c=1.6712(8) nm, β=104.846(8)°, V=1.6924(13) nm³, Z=8, μ=0.109 mm⁻¹, F(000)=752, and D_c=1.422 g cm⁻³. The thermal behavior and non‐isothermal decomposition kinetics of NDTAP were studied with DSC and TG‐DTG methods. The self‐accelerating decomposition temperature and critical temperature of thermal explosion are 195.5 and 208.2 °C, respectively. NDTAP presents good thermal stability and is insensitive.