用小药量至爆时间试验研究炸药爆发分解反应动力学

用小药量至爆试验测定了10种炸药:单质炸药3-硝基-1,2,4-三唑-5-酮(NTO)及其铵盐(ANTO)、铅盐(PbNTO)、钾盐(KNTO)、乙二胺盐(ENTO)、混合炸药JO-6、JOB-9003、JP-1、JD-1、JH-16在不同温度下的爆发延滞期(t_(ind)).依据谢苗诺夫方程lnt_(ind,i)=(E_σ)/(RT_i),-lnA_,由lnt_(ind,i)对1/T_i的关系,用最小二乘法计算了爆发分解反应的表观活化能(E_α)、指前因子(A_σ)和1 000 s时的热爆炸临界温度(T_b).用非线性等转化率积分法所得的表观活化能(E_σ)校验了由lnt_(ind,i)~1/T_i关系得到的E_σ值.借助热力学关系式,计算了爆发分解反应的活化反应热力学参量[活化自由能(ΔG~≠),活化焓(ΔH~≠)和活化熵(ΔS~≠].结果表明:(1) 以T_b和ΔG~≠作判据,知5种单质炸药和5种混合炸药的对热抵抗能力次序分别为:NTO＞ENTO＞ANTO＞KNTO＞PbNTO和JP-1＞JD-1＞JO-6＞JOB-9003＞JH-16;(2) E_α=E_α的事实佐证不同温度下爆发分解反应延滞期内分解深度相等,由此所得A_σ值可信,谢苗诺夫方程推导过程中A_σG(α)的假设合理.     

Low-Sensitivity Explosive Compounds for Low Vulnerability Warheads

Looking for explosives for Low Vulnerability Ammunitions leads to an interest in explosive molecules less sensitive than the usual nitramines (RDX, HMX). If TATB is quite convenient in terms of sensitivity, its performance is too low. The researches described here are related to synthesis and use of NTO (nitrotriazolone), another insensitive molecule. The synthesis by nitration of TO (triazolone) is easy and the two steps from available starting materials have been optimized. A comparison of desensitivation of PBX either by TATB or by NTO have been made. The sensitivity levels were found equivalent while the detonation velocity of the NTO based PBX was slightly higher. Unfortunately in this case, the failure diameter would be larger. The last part relates to an extensive characterization in terms of performance and vulnerability to fast cook off, slow cook off, bullet impact, shock sensitivity and sympathetic detonation of a NTO and HMX based PBX. This PBX, B 2214, was one of the first examples of explosive composition showing no sympathetic detonation, even in 248 mm large diameter.     

Studies on the critical temperature of thermal explosion for 3-Nitro-1,2,4-triazol-5-one (NTO) and its salts

The critical temperature of thermal explosion for 3-nitro-1,2,4-triazol-5-one (NTO) and its ethylenediammonium salt (ENTO), potassium salt (KNTO), copper salt (CuNTO) and lead salt (PbNTO) were obtained using the stationary theory of thermal explosion, the calculation formula of estimating the critical temperature of thermal explosion under non-isothermal DSC condition, and the determination method for the critical temperature of thermal explosion of small-scale solid explosive and its data treatment method. The results of the four methods are agreeable to each other, whose differences are within 5%. The results indicate that the heat-resistance ability of NTO and its salts and of the common explosives, cyclotetramethylenetetranitramine (HMX), cyclotrimethylenetrinitramine (RDX), pentaerythritoltetranitrate (PETN) and tetryl decreases in the order HMX > NTO > ENTO > KNTO > RDX > PETN > tetryl > PbNTO > CuNTO.     

Covalent and Ionic Insensitive High‐Explosives

Ongoing research into new insensitive energetic materials with low sensitivity toward accidental stimuli, high thermal stability and high performance characteristics is undertaken in many research groups worldwide. In order to obtain promising compounds, which fulfil the sensitivity, stability, and performance requirements, researchers use many different strategies. One of the most promising approaches is the synthesis of novel explosives with tailored physico‐chemical properties. In this review the synthesis and properties of some both covalent (NTO, TEX, FOX‐7, ADNP, DNPPs) and ionic (salts of ANDP and DNPP) insensitive explosives are presented, which are of high interest to this field of research.     

Microwave‐Assisted Quick Synthesis of Some Potential High Explosives

This paper reports a novel microwave‐assisted method for the synthesis of potential high explosives (HEs) such as 3‐nitro‐1,2,4‐triazol‐5‐one (NTO), bis‐(2,2‐dinitropropyl) nitramine (BDNPN), 4‐nitroimidazole (4‐NI) and 2,4,6,8,10,12‐hexanitro‐2,4,6,8,10,12‐hexaazaisowurtzitane (CL‐20). The high temperature thermal rearrangement of 1,4‐dinitroimidazole to 2,4‐dinitroimidazole was also reported using microwave radiation as heating source. The synthesized compounds were characterized by spectroscopic techniques and the data obtained confirmed their structures.     

Energetic Residues from the Detonation of IMX‐104 Insensitive Munitions

The development of insensitive munitions by NATO countries is an ongoing effort. Less‐sensitive ingredients in both explosives and propellants will ensure the protection of deployed troops against an unwanted reaction to an external stimulus on the munitions stockpile. In the US Army, current efforts are directed towards the development of melt cast insensitive explosive formulations. Various formulations, mainly based on DNAN and NTO, have been developed and are now being fielded. Our research goal is to measure the deposition rate of energetics compounds from various insensitive munitions detonation scenarios. Our hypothesis is that the relative insensitiveness of these formulations leads to slightly higher deposition rates than conventional explosive formulations. This paper describes detonation residues research on mortar rounds containing IMX‐104 explosive. Analyses indicate that high‐order detonation residues are slightly greater for this formulation than for conventional munitions. However, blow‐in‐place detonations (BIPs) resulted in much higher residues deposition, indicating that a larger donor charge is required for efficient detonation. The highly soluble compound NTO was particularly problematic, with BIP deposition approaching 95 % of the original load. Toxicological studies of NTO are not finalized, leaving considerable uncertainty regarding the feasibility of approving these rounds for distribution.     

DADE及其混合炸药的机械感度

为了解DADE以及含DADE的混合炸药的安全性能,用显微镜研究了DADE混合炸药降感机理。结果表明,在相同的试验条件下,DADE与TATB、NTO的机械感度相当,具有优良的安全性能;DADE粒度的大小对其感度影响很大,感度随粒度的减小而升高;在B炸药配方中,用DADE部分代替RDX后感度没有明显改变,完全代替RDX后降感效果十分明显。研究表明,DADE颗粒的合理级配以及表面包覆是降低DADE机械感度的重要途径。     

Estimations of Vapor Pressures by Thermogravimetric Analysis of the Insensitive Munitions IMX‐101, IMX‐104, and Individual Components

We have calculated the vapor pressures of the new explosives ordnances IMX‐101 and IMX‐104 and their respective components, 2,4‐dinitroanisole (DNAN), nitroguanidine (NQ), nitrotriazolone (NTO), and hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine (RDX) by the method of rising temperature thermogravimetric analysis. Clausius‐Clapeyron relationships were assumed for each case and the vapor pressures were estimated from the Langmuir equation over an appropriate temperature range just below substance melting/decomposition points. For vapor pressures extrapolated to room temperature, the rank with respect to decreasing volatility was found to be: DNAN>IMX‐104>IMX‐101>NQ>RDX>NTO. Interestingly, vapor pressure depression is observed in IMX formulations, where the formulation has a lower vapor pressure than its most volatile component, DNAN. The enthalpy of sublimation was determined for each substance and formulation from Clausius‐Clapeyron equations generated by analysis of the thermogravimetric data. The general trends in vapor pressures and sublimation enthalpies associated with the component materials were in good agreement with previous experimental and computational results. The results obtained by this study have importance for future investigations of IMX, specifically for chemical detection and assessment of environmental fate.     

Estimating Ambient Vapor Pressures of Low Volatility Explosives by Rising‐Temperature Thermogravimetry

Vapor pressure is a fundamental physical characteristic of chemicals. Some solids have very low vapor pressures. Nevertheless numerous chemical detection instruments aim to detect vapors. Herein we address issues with explosive detection and use thermogravimetric analysis (TGA) to estimate vapor pressures. Benzoic acid, whose vapor pressure is well characterized, was used to calculate instrumental parameters related to sublimation rate. Once calibrated, the rate of mass loss from TGA measurements was used to obtain vapor pressures of the 12 explosives at elevated temperature: explosive salts – guanidine nitrate (GN); urea nitrate (UN); ammonium nitrate (AN); as well as mono‐molecular explosives – hexanitrostilbene (HNS); cyclotetramethylene‐tetranitramine (HMX), 4,10‐dinitro‐2,6,8,12‐tetraoxa‐4,10‐diaza‐tetracyclododecane (TEX), cyclotrimethylenetrinitramine (RDX), pentaerythritol tetranitrate (PETN), 3‐nitro‐1,2,4‐triazol‐5‐one (NTO), 1,3,3‐trinitroazeditine (TNAZ), triacetone triperoxide (TATP), and diacetone diperoxide (DADP). Ambient temperature vapor pressures were estimated by extrapolation of Clausius‐Clapeyron plots (i.e. ln p vs. 1/T). With this information potential detection limits can be assessed.     

Some new observations on the structural and phase evolution of nickel titanate nanofibers

In this study, we report for the first time the synthesis of nickel titanate (NTO) nanofibers containing a mixture of ilmenite and spinel phases of NTO, at an atypical low temperature. Precursor nanofibers produced by sol-gel electrospinning were calcined at three different temperatures to produce the NTO nanofibers. Thermal analysis along with X-ray photoelectron spectroscopy confirmed the formation of non-crystalline stable phases of TiN and Ti-O-N that restrained the formation of ilmenite NTO, and the Ni-rich environment pushed the Ti atoms to tetrahedral sites to form a defective spinel structure. The crystallite size of spinel NTO was observed to increase as a function of the calcination temperature above 700 °C, as the activation energy for coalescence and growth of spinel NTO was favorable. NTO nanofibers obtained above the calcination temperature of 700 °C exhibited new band gap energy around 2.5 eV in Tauc plot. Oxygen vacancies in these ceramic nanofibers decreased as the calcination temperature was increased. A hypsochromic shift of 20 nm in the photoluminescence spectra suggested that the material had a Ni²⁺ rich NTO (spinel).     

Thermal Stability Studies Comparing IMX‐101 (Dinitroanisole/Nitroguanidine/NTO) to Analogous Formulations Containing Dinitrotoluene

The 2,4,6‐trinitrotoluene (TNT) replacement, IMX‐101, containing 43.5 % 2,4‐dinitroanisole (DNAN), 19.7 % 3‐nitro‐1,2,4‐triazol‐5‐one (NTO) and 36.8 % nitro‐guanidine (NQ), has been certified for use as an insensitive munition. IMX‐101 has passed standardized performance, stability, and aging tests but in some categories was not necessarily an improvement over TNT or RDX. This study compared the thermal stability of DNAN and another low‐melting nitroarene, 2,4‐dinitrotoulene (DNT). When examined individually, DNAN was more stable; but formulated in IMX‐101 with NTO and NQ, the opposite was true. In two part mixtures, NQ had a similar acceleratory effect on the decomposition of both nitroarenes, while NTO had a greater impact on DNAN than on NTO. Ammonia, a reported decomposition product of both NQ and NTO, also accelerated the decomposition of both DNAN and DNT, with a larger impact on DNAN. The formation of dinitroaniline, potentially due to the interaction between the nitroarenes and ammonia, was detected by LC/MS as a decomposition product when either nitroarene was combined with NTO and/or NQ, indicating that this molecule may play a significant role in the decomposition mechanism. While not advocating the use of DNT in insensitive munitions formulations, this study addresses the importance of chemical compatibility as a criterion for selecting replacement components in formulations.     

Characterization of PAX‐21 Insensitive Munition Detonation Residues

Insensitive high explosives are being used in military munitions to counteract unintended detonations during storage and transportation. These formulations contain compounds such as 2,4‐dinitroanisole (DNAN) and 3‐nitro‐1,2,4‐triazol‐5‐one (NTO), which are less sensitive to shock and heat than conventional explosives. We conducted a series of four tests on snow‐covered ice utilizing 60‐mm mortar cartridges filled with 358 g of PAX‐21, a mixture of RDX, DNAN, and ammonium perchlorate. Rounds were detonated high‐ and low‐order using a fuze simulator to initiate detonation. Blow‐in‐place (BIP) operations were conducted on fuzed rounds using an external donor charge or a shaped‐charge initiator. Results indicate that 0.001 % of the original mass of RDX and DNAN were deposited during high‐order detonations, but up to 28 % of the perchlorate remained. For the donor block BIPs, 1 % of the RDX and DNAN remained. Residues masses for these operations were significantly higher than for conventional munitions. Low‐order detonations deposited 10–15 % of their original explosive filler in friable chunks up to 5.2 g in mass. Shaped‐charge BIPs scattered 15 % of the filler and produced chunks up to 15 g. Ammonium perchlorate residue masses were extremely high because of the presence of large AP crystals, up to 400 μm in the recovered particles.     

Separation of NTO Related 1,2,4-Triazole-3-One Derivatives by a high performance liquid chromatography and capillary electrophoresis

This report describes a direct, rapid and sensitive method for separating and quantifying 5-nitro-1,2,4-triazole-3-one 1 (NTO) and 5-amino-1,2,4-triazole-3-one 2 . Analyses were performed on water and on soil containing compounds 1 and/or 2 , using reversed phase HPLC columns. A mixture of compounds 1 , 2 , Urazole 3 and 1,2,4-triazole-3-one 4 was well separated by HPLC on a Hypercarb column packed with porous graphitic carbon, or by capillary electrophoresis. Both methods could be used to detect such compounds in the environment and monitor their biological and chemical degradation.     

Thermal Decomposition of NTO: An Explanation of the High Activation Energy

Burning rate characteristics of the low‐sensitivity explosive 5‐nitro‐1,2,4‐triazol‐3‐one (NTO) have been investigated in the pressure interval of 0.1–40 MPa. The temperature distribution in the combustion wave of NTO has been measured at pressures of 0.4–2.1 MPa. Based on burning rate and thermocouple measurements, rate constants of NTO decomposition in the molten layer at 370–425 °C have been derived from a condensed‐phase combustion model (k=8.08⋅10¹³⋅exp(−19420/T) s⁻¹. NTO vapor pressure above the liquid (ln P=−9914.4/T+14.82) and solid phases (ln P=−12984.4/T+20.48) has been calculated. Decomposition rates of NTO at low temperatures have been defined more exactly and it has been shown that in the interval of 180–230 °C the decomposition of solid NTO is described by the following expression: k=2.9⋅10¹²⋅exp(−20680/T). Taking into account the vapor pressure data obtained, the decomposition of NTO in the gas phase at 240–250 °C has been studied. Decomposition rate constants in the gaseous phase have been found to be comparable with rate constants in the solid state. Therefore, a partial decomposition in the gas cannot substantially increase the total rate. High values of the activation energy for solid‐state decomposition of NTO are not likely to be connected with a sub‐melting effect, because decomposition occurs at temperatures well below the melting point. It has been suggested that the abnormally high activation energy in the interval of 230–270 °C is a consequence of peculiarities of the NTO transitional process rather than strong bonds in the molecule. In this area, the NTO molecule undergoes isomerization into the aci‐form, followed by C3‐N2 heterocyclic bond rupture. Both processes depend on temperature, resulting in an abnormally high value of the observed activation energy.     

Preparation,Characterization, and Catalytic Activity of Nanosized NiO and ZnO: Part 74

Nanocrystals of NiO and ZnO were prepared by a novel refluxing method and characterized by XRD and TEM. The average particles size of NiO and ZnO were found to be 6 and 31 nm, respectively, from the XRD patterns. These Transition Metal Oxide Nanocrystals (TMONs) were found to catalyze the thermal decomposition of 5‐nitro‐1, 2, 4‐triazol‐3‐one (NTO). Between the two TMOs, ZnO was found to have better catalytic activity than NiO. Kinetic parameters for the isothermal decomposition of NTO in presence and absence of these metal oxides were obtained using a model‐free isoconversional method. The activation energy for NTO, NTO+1 %NiO, and NTO+1 %ZnO was found to be 60.1, 52.1, and 47.9 kJ mol⁻¹ and a similar order was found from the explosion studies (36.1, 31.6, and 27.4 kJ mol⁻¹, respectively).     

Synthesis and Energetic Properties of Imidazolium and 2‐Methylimidazolium Salts of 3‐Nitro‐1,2,4‐Triazol‐5‐One

Two new energetic salts of 3‐nitro‐1,2,4‐triazol‐5‐one (NTO) were described. Imidazole and 2‐methylimidazole salt of NTO decomposes exothermically at 217 and 258 °C respectively. Detonation parameters calculated for 2‐methylimidazole salt are significantly smaller than that of 2,4,6‐trinitrotoluene (TNT) but these parameters estimated for imidazole salt are comparable with that of TNT. Structure of new compounds were investigated with NMR and IR spectroscopy. Impact and friction sensitivity determined for new compounds are smaller than for pure NTO, so they are more safe during handling.     

3-硝基-1,2,4-三唑-5-酮镁的合成及分子结构研究

用盐酸半缩脲和甲酸缩合 ,得 1,2 ,4 三唑 5 酮 (TO) ,采用直接硝化法合成了 3 硝基 1,2 ,4 三唑 5 酮 (NTO) ,利用碱式碳酸镁与NTO溶液进行反应合成了其镁盐并培养出单晶。通过X射线单晶结构分析法确定了分子结构 ,该化合物属单斜晶系 ,C2 /c点群。其分子式可表示为 [Mg(H2 O) 6](NTO) 2 ·2H2 O ,晶体学参数为 :a =2 .310 1(3)nm ,b =0 .6 472 (1)nm ,c =1.4118(3)nm ,β =12 4.0 5 (1)°,V =1.7489(5 )nm3,Z =4     

NTO及其盐的制备、表征与应用(续)

2．2．2晶体结构 杨利等人、冯长根等人、马海霞等人对制备的NTO胺盐的晶体结构进行了研究,确定了它们的分子结构和晶体学参数,李加荣对一些早期的研究成果进行了概述,结果见表12。研究表明：目前制备出的NTO胺盐全部为离子型化合物,除ANTO和GNTO各含1分子结晶水外,其他NTO胺盐均不含结晶水。     

2D sodium titanate nanosheet encapsulated Ag2O-TiO2 p-n heterojunction photocatalyst: Improving photocatalytic activity by the enhanced adsorption capacity

In a photocatalytic reaction, maintaining the high efficiency of photocatalyst under a low concentration of pollutants is a key challenge. In this work, a new 2D sodium titanate nanosheet encapsulated Ag₂O-TiO₂ (2D NTO/Ag₂O-TiO₂) p-n heterojunction photocatalyst is proposed to deal with this dilemma. Through a simple plasma electrolytic oxidation (PEO) treatment and ion exchange treatment, a classic Ag₂O-TiO₂ p-n heterojunction structure is prepared and used as the photoelectric conversion unit in the photocatalyst. Then, through a subsequent hydrothermal treatment, a 2D NTO film that serves as the adsorption unit in the photocatalyst can be produced on the surface of the Ag₂O-TiO₂ p-n heterojunction layer. Finally, the desired 2D NTO/Ag₂O-TiO₂ structure is formed. The photocatalyst exhibits superior photocatalytic performance including high degradation rate as well as excellent catalytic stability and durability by combining the high sunlight utilization efficiency and high photoelectric utilization efficiency of the Ag₂O-TiO₂ p-n heterojunction and the outstanding adsorption performance of the 2D NTO film. Therefore, the problem of photocatalytic slow kinetics under low pollutants concentration is perfectly solved. This work provides a new strategy for the structural design of high-performance photocatalysts.     

Synthesis and initial characterization of Amine Salts of 3-Nitro-1,2,4-Triazol-5-one

Seven amine salts of 3-nitro-1,2,4-triazol-5-one(NTO) have been prepared from inexpensive raw materials. The ammonium, ethylenediamine. hydrazine, and guanidinium homolog salts of NTO were synthesized; their methods of preparation are described. Results from initial characterization and small-scale sensitivity tests indicate that these compounds are thermally stable and moderately insensitive to impact. The heats of formation of these compounds were determined and their performances as gun-propellant ingredients were calculated based on these data. ¹³C-NMR spectra are also reported.