高能氧化剂硝仿肼及其推进剂研究的新进展

综述了欧美国家在研究高能氧化剂硝仿肼和以硝仿肼为基的固体推进剂等方面所取得的最新进展。介绍了硝仿肼的研制背景,并通过对硝仿肼物理化学特性数据的分析,证实了硝仿肼在固体推进剂中的实用价值。同时还介绍了以硝仿肼为氧化剂,ＧＡＰ为粘结剂,Ａｌ为燃料的固体推进剂配方的各种性能。     

国外硝仿肼研究新进展

介绍了近年来国外高能氧化剂硝仿肼的研究情况.研究表明,紫外-可见光光谱法有可能代替滴定法,从而提高硝仿肼纯度检测的准确性、降低质量控制成本;用水合肼代替肼和回收二氯甲烷和甲醇溶剂等方法有效降低了硝仿肼的生产成本而不影响产品质量;通过减少过量的水合肼和立即过滤硝仿肼粗产品等方法提高了硝仿肼的质量和产率;新的结晶技术如超声波结晶技术、加压结晶技术、共结晶技术及纳米粒子诱导结晶技术等能有效控制硝仿肼的晶粒粒度和长径比,降低感度并提高其稳定性.     

硝仿肼及其推进剂的研究进展

综述了20世纪90年代以来国外关于高能氧化剂硝仿肼及硝仿肼基新型固体推进剂研究的新进展。介绍了硝仿肼的合成方法、物理化学性能、晶体结构及不同结晶技术对硝仿肼形态及稳定性的影响。通过对硝仿肼爆炸性能及热安定性参数的分析，证实了其作为高能氧化剂的优异性能。通过HNF／Al／GAP、AP／Al／HTPB两种推进剂性能的对比分析，显示出硝肪肼及其推进剂的潜在价值。     

硝仿肼研究进展

介绍硝仿肼的理化性能,安全制备高纯度、不同粒径的硝仿肼新工艺,以及含硝仿肼的高能固体推进剂的特性。硝仿肼是一种高能不含卤素的氧化剂,采用硝仿肼氧化剂的推进剂,其比冲比当前最好的高氯酸铵/铅粉/丁羟胶推进剂约高8％;燃气无污染,可用于开发高能洁净固体推进剂。     

泰安、硝仿肼热分解动力学的初步研究

本文采用国产4.1型示差精密热天平对泰安、硝仿肼的热分解进行了初步研究。由DTA—TG实验曲线上的数据计算出它们的热分解动力学参数。前言用等温法测得的泰安热分解动力学参数已有报导。我们采用非等温法所测得的参数与等温法所得到的数值基本一致,说明用DTA—TG法测定火炸药热分解动力学参数,不仅有参考价值,而且该法要比等温法方便,迅速得多。用DTA—TG法研究硝仿肼的热分解曾有过报导,但没有计算动力学参数。我们采用该法研究了硝仿肼的热分解並求出了它的热分解动力学参数。一、泰安的热分解动力学 (一) 样品     

硝仿(NF)高安全制备工艺研究

以丙二酸二甲酯和甲酰胺为原料,通过缩合环化制备出4,6-二羟基嘧啶(DHP),然后经硝化-水解反应制备出硝仿(NF),利用紫外光谱、核磁共振谱、红外光谱以及质谱等进行了结构表征。探讨了DHP硝化-水解的反应机理,确定了制备硝仿最佳工艺条件为:n(硝酸)∶n(DHP)=5∶1、n(硫酸)∶n(硝酸)=3.5∶1.0、反应温度45℃、反应时间2 h,收率为80.1%;通过改进硝仿的分离条件,可显著提高工艺的安全性;以自制的硝仿为原料,合成出纯度为98.9%的硝仿肼。     

泰安、硝仿肼热分解动力学的初步研究

本文采用国产4.1型示差精密热天平对泰安、硝仿肼的热分解进行了初步研究。由DTA—TG实验曲线上的数据计算出它们的热分解动力学参数。     

含能材料中间体硝仿的研究进展

硝仿是一种重要的含能材料中间体,用于合成硝仿系炸药及硝仿盐类高能氧化剂。详细介绍了国内外在硝仿的制备和分离方面的研究进展情况。其中制备方法主要介绍了乙炔硝化法、四硝基甲烷法、丙酮硝化法、异丙醇硝化法、嘧啶-4,6-二酮衍生物硝化-水解法。分离方法主要介绍了二次恒沸蒸馏法、萃取法、盐析法、萃取-蒸馏结合法。同时分析了各种方法的优劣。     

含硝仿肼的复合推进剂二次烟雾特征信号研究

为研究新型氧化剂硝仿肼(HNF)替代高氯酸铵(AP)后复合推进剂的能量特性和烟雾特征信号性能,采用最小自由能原理进行了配方的化学平衡性能计算。在分析计算结果基础上,采用烟雾特征信号计算特征值模型分析了不同含量HNF对复合推进剂二次烟雾特征信号性能的影响规律。     

含硝仿肼的固体推进剂能量特性研究

研究了三种含硝仿肼 (HNF)的固体推进剂 HNF/GAP/A1、NC/NG/HNF/RDX、NC/NG/HNF/RDX/Al的能量特性 ,绘制了等性能三角图 ,可形象、直观地看出这类推进剂的比冲、燃烧温度与配方组分之间的关系     

Combustion of energetic materials controlled by condensed-phase reactions

A combustion model controlled by condensed-phase reactions (c-phase combustion model) is considered. Based on an analysis of numerous thermocouple studies of combustion of energetic materials, it is shown that the condensed phase is heated in the combustion wave to the maximum possible temperature—the boiling point at this pressure. It is established that the combustion of representatives of the class of onium salts such as ammonium perchlorate, ammonium nitrate, ammonium dinitramide, and hydrazinium nitroformate over a wide range of pressures and initial temperatures obeys the the c-phase-model. The kinetic parameters of the burning-rate controlling reaction of these salts are given.     

Thermal and catalytic decomposition of HNF and HAN liquid ionic as propellants

Binary aqueous hydroxylammonium nitrate (HAN: [NH₃OH]⁺[NO₃]⁻) and hydrazinium nitroformate (HNF: [N₂H₅]⁺[C(NO₂)₃]⁻) have been prepared, then thermally and catalytically decomposed. The HAN solutions were prepared with different concentrations (20, 40, 79 wt.%), whereas HNF solution contains is 40 wt.% due to its lower solubility limit (about 50 wt.%). The catalyst was prepared by impregnation of modified support (Si-modified alumina) with monometallic active phase precursor (platinum) and characterized by transmission electron microscopy, X-ray diffraction and chemisorption. The reactions were followed by thermal analysis and by using a constant volume batch reactor. This work shows the essential effect of the monopropellant concentration to determine the best formulation for an industrial application. Moreover, HAN laboratory made solutions are more efficient for catalytic decomposition due to the absence of stabilizer to inhibit the catalyst. The Pt(10%)/Al₂O₃Si + HAN_79% lab association shows lower decomposition temperatures (down to room temperature), larger reaction rates and leads to higher amount of gaseous products, giving the most efficient system. With the same catalyst, HNF solution gave lower performances than HAN solutions, suggesting that the catalyst needs to be improved for this oxidizer.     

Isocyanate‐Free Curing of Glycidyl Azide Polymer with Bis–propargylhydroquinone

Bis‐propargylhydroquinone (BPHQ) is an alkyne functionalized isocyanate‐free curing agent for hydroxyl terminated azido polymers. Conventionally, glycidyl azide polymer (GAP) is cured by isocyanate based curatives, which are toxic and hygroscopic in nature. The reaction between hydroxyl end group of GAP and isocyanate is highly sensitive to moisture causing voids in the propellant, leading to poor mechanical properties. Herein, an alternate approach was adapted to exploit 1,3‐dipolar cycloaddition reaction between azido group of GAP and the triple bond (–C≡CH) of BPHQ without catalyst at 50 °C forming triazole crosslinked polymer. The curing behavior of GAP‐BPHQ system was studied by rheological method and based on the results the gel time was determined. In addition, the reaction between GAP and BPHQ was carried out with various GAP/BPHQ ratios (0.9 to 2.5) and effects on mechanical properties of resulting triazole polymers were investigated. Post curing hardness of GAP‐BPHQ binder system was tested by surface Shore‐A hardness measurement. The compatibility of BPHQ with energetic oxidizers such as ammonium dinitramide (ADN) and hydrazinium nitroformate (HNF) were also studied by differential scanning calorimetery (DSC) technique and showed good compatibility. The activation energy (E _a) of cured GAP‐BPHQ binder was evaluated by DSC using Ozawa and Kissinger methods and are found to be 33.55 and 33.16 kcal mol^–1, respectively. The advantage of this curing system between GAP and BPHQ is unaffected by moisture as compared to isocyanate based urethane systems and also no need to control humidity during the processing of propellant. The experimental results reveal that triazole crosslinked polymer system could be a better choice to develop novel energetic binder systems for explosives as well as propellants composition with improved performance and eco‐friendly nature.     

DFT and MP2 Study of Intermolecular Interaction of 5‐Aminotetrazole and Hydrazine: Enthalpy of Formation of Hydrazinium 5‐Aminotetrazolate in the Gas Phase

The tautomerism of all possible forms of 5‐aminotetrazole ( AT1 – AT7 ) in the gas phase and continuum solvent was studied theoretically. The calculations were separately performed at the MP2 and CAM‐B3LYP levels of theory, using the 6‐311++G(d,p) basis set. It was found that 5‐aminotetrazole in the 2H form ( AT1) is the most stable isomer in both the gas phase and in solution. In addition, the aggregation of various isomers of 5‐aminotetrazole with hydrazine was investigated in the gas phase and in solution. Finally, the standard enthalpy of formations of the different structures of hydrazinium 5‐aminotetrazolate was determined in the gas phase. Using the calculated standard enthalpy of formation of different structures of hydrazinium 5‐aminotetrazolate in the gas phase and considering their Boltzmann population ratios, a single value has been reported for the standard enthalpy of formation of hydrazinium 5‐aminotetrazolate considering all of the tautomers. The calculated values are in excellent agreement with the experimentally reported heat of formation for the hydrazinium 5‐aminotetrazolate.     

Hydrazinium salts as thermally latent initiators in the polymerization of glycidyl phenyl ether

Novel hydrazinium salts, N,N‐dimethyl N‐benzyl N′‐benzyl N′‐benzoyl hydrazinium hexafluoroantimonate (2) and N,N‐dimethyl N‐benzyl N′‐(2‐propyl) N′‐benzoyl hydrazinium hexafluoroantimonate (3) were synthesized from hydrazinium salt (1) with the corresponding alcohol. Their initiator activities were examined in the polymerization of glycidyl phenyl ether (GPE). The polymerization of GPE did not proceed with 2 and 3 below 60 and 100°C but proceeded rapidly above those temperatures, respectively. It was found that 1–3 served as thermally latent initiators in the polymerization of GPE. The initiating species and terminating species were identified as the proton or alkyl cation and aminimide, respectively. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1439–1442, 2005     

1-甲基-5-硝亚胺基四唑及其盐的合成与表征

以甲胺和叠氮化氰为原料经缩合作用合成了1-甲基-5-氨基四唑,在发烟硝酸最佳用量为5 mL、室温和反应时间20h条件下,经硝化得到1-甲基-5-硝亚胺基四唑.通过1-甲基-5-硝亚胺基四唑作阴离子和5种高氮含能阳离子的反应,分别合成出1-甲基-5-硝亚胺基四唑铵盐、1-甲基-5-硝亚胺基四唑肼盐、1-甲基-5-硝亚胺基...     

An efficient one-pot protocol for regioselective synthesis of 3-aryl-6,8-dialkyl-7-thioxo-7,8-dihydropyrimido[4,5-c] pyridazine-5(6H)-ones

A series of 3-aryl-6,8-dialkyl-7-thioxo-7,8-dihydropyrimido[4,5-c]pyridazine-5(6H)-one derivatives have been regioselectively synthesized via the one-pot three-component reaction of 1,3-dimethylthiobarbituric acid and 1,3-diethylthiobarbituric acid with various arylglyoxals in the presence of hydrazinium dihydrochloride in warm ethanol. These new substituted pyrimidopyridazines may be potential monoamine oxidase inhibitors.     

Les proprietes electrochimiques des diphenylamines et de leurs produits d''oxydation en milieu organique—II. Proprietes des diaryl-5,10 dihydro-5,10 phenazines et des tetraarylhydrazines

This paper is the second in a series devoted to the electrochemical oxidation of diphenylamines and of coupling products obtained from them. Anodic processes with 5,10-diaryl 5,10-dihydrophenazines and tetraarylhydrazines in acetonitrile are studied by voltammetry and coulometry. Absorption and epr spectra of the corresponding cation radicals are described. This study gives the opportunity to discuss an anodic substitution involving a di-cation as the reactive intermediate. Aged solutions of electrogenerated hydrazinium radicals in neutral media and the acidic degradation of tetraarylhydrazines give a similar mixture the composition of which depends upon the nature of the para substituant on the aromatic ring.     

Nanocomposites: An Ideal Coating Material to Reduce the Sensitivity of Hydrazinium Nitroformate (HNF)

Hydrazinium nitroformate (HNF), an energetic and eco‐friendly oxidizer, was desensitized successfully by changing its crystal size and shape and by coating with a nanocomposite. During crystallization, various methods were tried out which include mechanical stirring, ultrasound and using crystal shape modifiers (CSMs). Experimental results showed that the multi‐pronged approach to control the shape and size of the crystals by a careful choice of CSMs and crystallization method worked well to counter the preferential axial crystals growth, thus shifting the long needles to near cubical shape. Among various coating agents, a hydroxy‐terminated poly butadiene (HTPB)‐based clay nanocomposite was found to be most effective for reducing the friction and impact sensitivity of HNF. A Scanning Electron Microscope (SEM) coupled with Energy Dispersive Spectroscopic (EDS) analysis was found to be a very reliable and most useful technique to assess the extent of coating on HNF so as to achieve a consistent figure of insensitivity. The coating material was stable as well as compatible with the HNF crystals as revealed by thermal analysis.     

Selective Extraction and Detection of Hg2+ in Aqueous Solution by using Rhodamine Dye-Modified Silica Gel

Novel silica gel-immobilized rhodamine (SGR) anchored by hydrazinium hydrate was synthesized. The selectivity and adsorption ability of the SGR for metal cations were investigated with fluorophotometry and atomic absorption spectrophotometery, respectively. The SGR exhibits high selectivity and adsorption capacity for Hg²⁺. The maximum static adsorption capacity of the SGR for Hg²⁺ was 25.8 μmol g^?1. The linear response range covers a concentration range of Hg²⁺ from 20 ppb to 2000 ppb and the detection limit is 10 ppb. The determination of Hg²⁺ in real water samples displays satisfactory results, and the SGR can be used repeatedly by treating with a solution of tetrabutylammonium hydroxide.