Selection and Synthesis of Energetic Heterocyclic Compounds Suitable for Use in Insensitive Explosive and Propellant Compositions

The rationale behind developing insensitive energetic compounds (IECs) for incorporation into insensitive munition (IM) formulations (rather than the alternative approach of desensitizing higher energy but sensitive compounds) is discussed. With the aim of selecting a maximum of 2–3 IECs suitable for use in insensitive explosive and propellant compositions, a survey of the literature on IECs published in the last 20 years was carried out. From around 50 candidates, a selection was made of eight prime candidates, all heterocyclic compounds (principally monocyclic or fused‐ring bicyclic compounds of the di‐ or triazine, triazole or oxadiazole classes), which displayed explosive performance significantly better than that of the ubiquitous IEC, TATB. The criteria for inclusion of compounds in these listings are described. Screening of the eight candidate compounds against further performance criteria reduced the list to five compounds which were evaluated in detail – these were: CL‐14 (5,7‐diamino‐4,6‐dinitrobenzofuroxan), ANPZ‐i (2,5‐diamino‐3,6‐dinitropyrazine), NNHT (2‐nitrimino‐5‐nitro‐hexahydro‐1,3,5‐triazine), NTAPDO (5‐nitro‐2,4,6‐triaminopyrimidine‐1,3‐dioxide), and PANT [4‐(picrylamino)‐5‐nitro‐1,2,3‐triazole]. A detailed analysis of scale‐up issues associated with each compound was then made, including cost and availability of precursors, hazards (chemical and explosive), effluent streams, and other scale‐up issues (e.g. materials of plant construction). A further downselection using these criteria gave the present short‐list comprising three compounds (the first three listed above) and further evaluation is in progress. The results of this study, funded by UK MOD, comprise the UK contribution to a nine‐nation European research collaboration in the EUCLID Common European Priority Area 14 “Energetic Materials”, as part of a five‐year project which commenced in October 2003.     

Energetic Materials: Crystallization,Characterization and Insensitive Plastic Bonded Explosives

The product quality of energetic materials is predominantly determined by the crystallization process applied to produce these materials. It has been demonstrated in the past that the higher the product quality of the solid energetic ingredients, the less sensitive a plastic bonded explosive containing these energetic materials becomes. The application of submicron or nanometric energetic materials is generally considered to further decrease the sensitiveness of explosives. In order to assess the product quality of energetic materials, a range of analytical techniques is available. Recent attempts within the Reduced‐sensitivity RDX Round Robin (R4) have provided the EM community a better insight into these analytical techniques and in some cases a correlation between product quality and shock initiation of plastic bonded explosives containing (RS‐)RDX was identified, which would provide a possibility to discriminate between conventional and reduced sensitivity grades.     

四嗪类高氮含能化合物的合成与表征

以硝酸胍、水合肼、乙酰丙酮为起始原料制得3,6-对(3,5-二甲基吡唑)-1,2,4,5-四嗪(BT);以BT为前躯体,经亲核取代得到几种1,2,4,5-四嗪类高氮含能化合物,包括3-肼基-6-(3,5-二甲基吡唑)-1,2,4,5-四嗪(HDM PT)、3-叠氮基-6-(3,5-二甲基吡唑)-1,2,4,5-四嗪(IADM PT)、3,6-二肼基-1,2,4,5-四嗪(DHT)、3,6-二叠氮基-1,2,4,5-四嗪(D IAT)、3,6-二胍基-1,2,4,5-四嗪(DGTZ)。采用红外、质谱、核磁等分析手段对其进行了表征。     

唑类含能离子化合物的合成研究进展

综述了以咪唑、三唑、四唑以及五唑等唑类化合物为母体的一些含能盐的合成,系统总结了这类新型含能材料的熔点、密度、生成焓等理化性能以及爆轰性能,并分析了分子结构及取代基对含能盐性能的影响。对唑类含能盐在火炸药和推进剂等方面的应用进行了展望。附36篇参考文献。     

唑系含能化合物的特征

从密度、感度、熔化分解点、焓值等方面系统地概述了唑系含能化合物的特征。     

Bishydrazinium and Diammonium Salts of 4,4′,5,5′‐Tetranitro‐2,2′‐biimidazolate (TNBI): Synthesis and Properties

The diammonium ( 1 ) and bishydrazinium ( 2 ) salts of 4,4′,5,5′‐tetranitro‐2,2′‐biimidazolate (TNBI) were synthesized and their physical properties as well as predicted explosive performance characteristics are described. These dianionic salts are easily formed in good yields by reaction of TNBI with aqueous solutions of the cationic species. TNBI is synthesized from 2,2′‐biimidazole, which is ultimately synthesized by the condensation of aqueous glyoxal with ammonium acetate. The compounds were characterized by NMR spectroscopy, vibrational (FT‐IR and Raman) spectroscopy, elemental analysis, thermal analysis (DSC, VTS and calorimetry), and small scale safety testing (impact, friction, ESD). The measured densities and heats of formation are reported. The materials show promise for use in IM explosive and propellant formulations due to the combination of their calculated performances, thermal stability and insensitivity to stimuli.     

The Insensitive Energetic Material Trifurazano‐oxacycloheptatriene (TFO): Synthesis and Detonation Properties

The high‐energy insensitive compound trifurazano‐oxacycloheptatriene (TFO) was first by synthesized through special etherification. The reaction mechanism and reaction conditions were discussed. TFO has a low melting point (78.6 °C) and good compatibility. TFO is insensitive to impact and friction and has similar detonation velocity (7.7 km s⁻¹) and detonation pressure (35.6 GPa) to RDX.     

Fabrication and Properties of Insensitive CNT/HMX Energetic Nanocomposites as Ignition Ingredients

Cyclotetramethylene tetranitramine (HMX)‐coated carbon nanotube (CNT) nanocomposites with uniform structures were prepared using the recrystallization method. Characterization (SEM, TEM, XRD, BET, etc.) was performed to determine the micromorphology, crystal structure, and specific surface area. The energetic particles were homogeneously distributed on the surfaces of the CNTs, and the maximum thickness of the coating layer was approximately 120 nm, whereas the average crystal size was less than 50 nm. The test results of the thermal behavior showed that the thermal decomposition temperature decreased as the CNT content increased, and the maximum thermal conductivity was approximately 27.3 times higher than that of pure HMX. The sensitivities of the CNT/HMX nanocomposites to impact, friction, and shock were maximally reduced by 73 %, 29 %, and 74 % compared with those of pure HMX, respectively, which demonstrated a significant safety improvement. In the CNT/HMX nanocomposites, aluminum and ferric oxide were used to fabricate a new type of ignition composition. Based on comparative studies, the results showed that the ignition composition was porous and that its particles were more evenly distributed compared with the conventional counterparts. The thermal conductivity was improved by 21 %. The impact and friction sensitivities were also maximally reduced by 21 % and 27 %, respectively. The combustion heat was also increased by 9 % compared with that of a mixture of the same components.     

含钾盐消焰剂的硝化棉基钝感推进剂燃烧性能研究

了含钾盐的硝化棉基钝感推进剂的燃烧性能。结果发现,钾冰晶石的加入严重地破坏了钝感推进剂的平台燃烧效应,而消焰剂ＫＤ对平台的破坏作用较小。含ＫＤ的推进剂燃速率和平台范围可通过组合催化剂的变化来调节。ＢＴＴＮ取代ＴＭＥＴＮ后,燃速有所增加,平台效率得以保持。添加硝基胍使得推进剂在８－９ＭＰａ燃速发生“突跃”高压下有平台区出现。     

不敏感含能材料MAD-X1的合成及性能

以草酸与氨基胍碳酸氢盐为原料,经脱水成环、重氮化取代、氧化、中和反应合成了不敏感含能材料1,1′-二羟基-3,3′-二硝基-5,5′-联-1,2,4-三唑二羟胺盐(MAD-X1),总收率为41.2%,采用红外光谱、1 H NMR、13 C NMR及元素分析对产物的结构进行了表征。探讨了一锅法合成中间体5,5′-二氨基-3,3′-联-1,2,4-三唑(DABT)的机理及亚硝酸钠与硫酸摩尔比对重氮化取代反应收率的影响,对MAD-X1的热性能进行了分析,用NASA-CEA程序计算了MAD-X1-CMDB推进剂的能量特性。结果表明,采用一锅法合成DABT,周期短、收率高(75.1%),亚硝酸钠与硫酸的最佳摩尔比为2.4∶1,酸化试剂为浓盐酸,MAD-X1的热分解峰温度为248.7℃;MAD-X1-CMDB推进剂的理论比冲和特征速度分别为2 449.6N·s/kg和1 540.7m/s。     

多硝基吡啶类化合物的合成及应用研究进展

综述了2,6-二氨基-3,5-二硝基吡啶(ANPy)及其氧化物(ANPyO)、2,4,6-三氨基-3,5-二硝基吡啶(TANPy)及其氧化物(TANPyO)、2,4,6-三硝基吡啶(TNPy)及其氧化物(TNPyO)等多硝基吡啶类含能化合物的合成及应用研究进展。ANPyO的爆轰性能和安全性能与三氨基三硝基苯(TATB)接近,可作为高能钝感炸药;理论预测TANPy比TATB钝感;TNPyO具有良好的热稳定性和化学稳定性。预计这些多硝基吡啶类含能化合物在钝感炸药、低易损发射药和钝感推进剂领域中有良好的应用前景。     

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.     

偶氮四唑类高氮含能化合物的合成及表征

以5-氨基四唑为原料,合成了3种偶氮四唑类高氮含能化合物（偶氮四唑铵盐（AZT）、偶氮四唑胍盐（GZT）及偶氮四唑三氨基胍盐（TAGZT））,利用IR、NMR、DSC、熔点测试和元素分析鉴定了其结构,简要地介绍了其爆炸性能.研究表明,作为新型高氮含能材料,偶氮四唑盐具有高的正生成焓、成气量大、燃烧无烟或少烟、燃后剩余残渣少以及不吸湿等特点,且具有良好的爆炸性能,可作为新型气体发生剂、低特征信号推进剂、低烟或无烟烟火剂以及高能炸药的重要组分.     

新型叠氮-均三嗪类含能化合物的合成与表征

以三聚氯氰为前驱体,通过亲核取代反应,得到硝基芳环均三嗪中间体;再将中间体与NaN3反应,得到4种新型叠氮-均三嗪类含能化合物:4,6-二叠氮基-N-(2-硝基苯基)-1,3,5-三嗪-2-胺基、4,6-二叠氮基-N-(3-硝基苯基)-1,3,5-三嗪-2-胺基、4,6-二叠氮基-N-(4-硝基苯基)-1,3,5-三嗪-2-胺基、2,4-二叠氮基-6-(2-(2,4-二硝基苯基)肼基)-1,3,5-三嗪;采用IR、1 H NMR、13 C NMR、MS等对4种化合物的结构进行了表征;采用TG-DSC研究了4种化合物的热力学性能;通过B3LYP/6-311G**方法预估了化合物的理论密度、标准生成焓、爆速和爆压。结果表明,4种化合物具有较好的热稳定性,叠氮基的引入使其具有较高的正生成焓。综合4种叠氮-均三嗪类含能化合物的性能,化合物2,4-二叠氮基-6-(2-(2,4-二硝基苯基)肼基)-1,3,5-三嗪的性能较佳。     

Studies of Novel Heterocyclic Insensitive High Explosive Compounds: Pyridines,Pyrimidines, Pyrazines and Their Bicyclic Analogues

The rationale behind using heterocyclic compounds [1], particularly nitrogen heterocycles, as higher energy insensitive high explosives is discussed, including the potential advantages compared with carbocyclic compounds. The types of functional groups used to impart energy to heterocyclic nuclei, whilst maintaining insensitivity, and methodologies for their introduction, are covered. The latter include nitration (by conventional and clean synthetic methods), amination, and oxidation (on ring heteroatoms and of exocyclic amino groups). Strategies for maximising the energetic content of a given heterocyclic nucleus are also examined. The syntheses of specific examples at QinetiQ are described, based on the following nuclei: pyridine, pyrimidine, pyrazine, quinoxaline, quinazoline, pteridine and purine. Strategies for obtaining the desired amino‐nitro derivatives and their heterocyclic N‐oxides are outlined. Optimisation of the synthetic routes for several candidates is discussed. The physical, explosive and thermal properties of the more successful candidates are described, with suggestions for their potential application in military stores.     

呋咱含能化合物的合成及其衍生物反应研究进展

阐述了二肟脱水和氧化呋咱还原2种构建呋咱环的主要方法,以及氨基取代呋咱衍生物、硝基取代呋咱衍生物和氰基取代呋咱衍生物的反应;列举了几种典型的呋咱含能化合物如二硝基呋咱(DNF)、二氨基偶氮呋咱(DAAF)、3,4–双(4′–硝基呋咱–3′–基)氧化呋咱(DNTF)、呋咱醚类化合物(FOF–1,FOF–2,FOF–13)和稠环类呋咱含能化合物(MNOTO、4,5,9,10–四硝基–1,4,5,8–四氮杂氢化萘(2,3,–6,7)并双呋咱)的合成方法及性能。     

一种新型叠氮含能固化剂的合成及性能

为提高黏合剂体系的力学性能,通过叠氮聚醚多元醇与六亚甲基二异氰酸酯（HDI）反应合成了一种新型叠氮多异氰酸酯含能固化剂（EC）。研究了料比、反应温度、后处理方法等因素对反应的影响。DSC结果表明,EC的最大热分解温度为252．89℃,玻璃化温度为-47．13℃。EC／GAP胶片的最大热分解温度为254．56℃,玻璃化温度为-45．78℃。EC／GAP／50％TEGDN体系具有良好的物理和化学相容性,制备的胶片有两个分解放热峰,对应的最大热分解温度分别为213．05℃和250．89℃,玻璃化温度为-69．08℃。GAP／EC胶片在＋20℃下的拉伸强度和断裂伸长率分别为0．67MPa和129％,优于GAP／N100体系的0．53MPa和56．5％。     

Salts of Tetrazolone – Synthesis and Properties of Insensitive Energetic Materials

Tetrazolone (5‐oxotetrazole, 1 ) is formed by diazotization of 5‐aminotetrazole in the presence of CuSO₄. Nitrogen‐rich salts such as guanidinium ( 2 ), 1‐aminoguanidinium ( 3 ), 1,3‐diamino‐guanidinium ( 4 ), 1,3,5‐triamino‐guanidinium ( 5 ), ammonium ( 6 ), hydrazinium ( 7 ) and the hydroxylammonium ( 8 ) salts of tetrazolone were prepared by facile deprotonation or metathesis reactions. All compounds were characterized by single‐crystal X‐ray diffraction, vibrational spectroscopy (IR and Raman), multinuclear NMR spectroscopy, elemental analysis and DSC measurements. The heats of formation of 2–8 were calculated using the atomization method based on CBS‐4M enthalpies. With these values and the experimental (X‐ray) densities several detonation parameters such as the detonation pressure, velocity, energy and temperature were computed using the EXPLO5 code (V.5.04). In addition, the sensitivities towards impact, friction and electrical discharge were tested using the BAM drop hammer and friction tester as well as a small scale electrical discharge device.     

Synthesis,Characterization and Properties of Nitropolybutadiene as Energetic Plasticizer for NHTPB Binder

The nitration of low molecular weight polybutadiene (PB) by a convenient and inexpensive procedure was investigated. To retain the unique physico‐chemical properties of the plasticizer, it was nitrated to an extent of 10 % double bonds. The product nitropolybutadiene (NPB) was characterized by FT‐IR and ¹H NMR spectroscopy as well as GPC, DSC, and TGA methods. The kinetic parameters for the decomposition of NPB from room temperature to 400 °C were obtained from non‐isothermal DSC. The changes in glass transition temperature (T _g) and inert uncured binder systems were used for determination of its efficiency as plasticizer. NPB was used in cured and unfilled nitro‐hydroxyl terminated polybutadiene (NHTPB) binder. Isothermal thermogravimetric analysis (Iso‐TGA) was employed to determine the migration rate in cured and unfilled HTPB binder systems compared to the dioctyladiphate (DOA) plasticizer. It was found that the exudation of the NPB plasticizer is slower than that of the DOA plasticizer. Thus, the NHTPB/NPB binder system (binder/plasticizer) presents more convenient mechanical properties than HTPB/DOA and is a promising new energetic binder system for polymer bonded explosives.     

A New General Correlation for Predicting Impact Sensitivity of Energetic Compounds

This paper describes an improved simple model for prediction of impact sensitivity of different classes of energetic compounds containing nitropyridines, nitroimidazoles, nitropyrazoles, nitrofurazanes, nitrotriazoles, nitropyrimidines, polynitroarenes, benzofuroxans, polynitroarenes with α‐CH, nitramines, nitroaliphatics, nitroaliphatic containing other functional groups, and nitrate energetic compounds. The model is based on some molecular structural parameters. It is applied for 90 explosives, which have different molecular structures. The predicted results are compared with outputs of complex neural network approach as one of the best available methods. Root mean squares (rms) of deviations of different energetic compounds are 24 and 49 cm, corresponding to 5.88 and 12.01 J with 2.5 kg dropping mass, for new and neural network methods, respectively. The novel model also predicts good results for eight new synthesized and miscellaneous explosives with respect to experimental data.