磷钨酸催化低沸点芳烃液相硝化反应

研究了磷钨酸对苯、甲苯和氯苯液相硝化反应的催化活性,考察了反应温度、反应时间、硝酸与芳烃摩尔比对芳烃转化率和产物选择性的影响。实验结果表明,磷钨酸对低沸点芳烃液相硝化反应具有显著的催化活性,在优化的条件下,苯、甲苯和氯苯的转化率分别为98.0%,99.5%,100.0%。苯硝化反应产物中无多硝基苯生成,硝基苯的选择性高;甲苯硝化反应产物中,对硝基甲苯和邻硝基甲苯的摩尔比达到1.08,较经典的方法明显提高;氯苯硝化反应采用发烟硝酸作硝化剂,氯苯转化率高于以浓硫酸为底酸、硝酸为硝化剂的方法。     

H_2SO_4/MCM-41上苯的气相硝化反应

研究了在H2SO4/MCM-41上,以稀硝酸(60%～70%)作硝化剂苯的气相硝化反应。实验结果表明,在苯与硝酸摩尔比为2 5、MCM-41上硫酸负载量(质量分数)为20%、反应温度150～160℃、空速3279h-1条件下,硝基苯产率大于99%。维持其它实验条件不变,提高空速到5700h-1时,硝基苯产率达到91 2%;连续反应240h,催化剂活性没有明显下降。     

4,10-Dinitro-2,6,8,12-tetraoxa-4,10-diazatetracyclo[5.5.0.05,903,11]dodecane Synthesis

4,10-Dinitro-2,6,8,12-tetraoxa-4,10-diazatetracyclo[5.5.0.0^5,90^3,11]dodecane (TEX) was obtained by nitrolysis of 1,4-diformyl-2,3,5,6-tetrahydroxypiperazine reaction using a mixture of fuming nitric acid and concentrated sulfuric acid. The optimal process temperature was 54–56°C. The yield of the synthesis depends inter alia on the rate the reactants are introduced into the reaction medium and on the time of conditioning of the reaction mixture. A maximal yield of ca. 40% was achieved at the reactant addition time of 2 h and conditioning time of 2 h. None of the other nitrating mixtures examined proved superior to the conventional nitrating mixture. The product was examined by high-performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR), and differential scanning calorimetry (DSC) techniques and the results are reported.     

Mechanochemical Nitration of Aromatic Compounds

Nitration of organic compounds is necessary to produce many energetic materials, such as TNT and nitrocellulose. The conventional nitration process uses a mixture of concentrated sulfuric and nitric acids as nitrating agents and multiple solvents. The chemicals are corrosive and require special handling and disposal procedures. In this study, aromatic nitration has been achieved using solvent-free mechanochemical processing of environmentally benign precursors. Mononitrotoluene was synthesized by milling toluene with sodium nitrate and molybdenum trioxide as a Lewis acid catalyst. Several parameters affecting the desired product yield were identified and varied. A number of byproducts, i.e., dimers of toluene were also produced, but the selectivity was observed to increase with increasing mononitrotoluene yield. Both absolute mononitrotoluene yields and selectivity of its production increased with the increase in the energy transferred to the material from the milling tools.     

硝酸环己酯的优化合成研究

硝酸环己酯是一种有效的柴油十六烷值改进剂。以硝酸－醋酐混合物为环己醇的硝化剂，利用正交试验设计描述了硝酸环己酯的优化合成。分析了几种试验因素对产品收率和纯度的影响，并从硝化作用的角度对这些影响进行了探讨。     

超重力技术在碳四烷基化中的应用

介绍了超重力技术的原理、工程化实现的手段及其技术特点和优势。对硫酸法C_4烷基化的反应原理和技术特点作了分析阐述,对超重力技术应用于浓硫酸C_4烷基化过程的应用研究情况进行了介绍。超重力技术应用于C_4烷基化反应,由于酸烃反应体系混合效果得到强化,与实验室搅拌式烷基化反应比较,C_8组分质量分数提高27.9%,C_9~+组分质量分数降低22.1%,产品辛烷值(RON)提高9.0单位。与已有成熟的工业化浓H_2SO_4法烷基化工艺比较,得到的烷基化油RON值可提高1.9～3.9单位。将超重力技术应用于硫酸法烷基化,对于改善提升其反应效果和技术水准,更好地满足国内油品质量升级需求,具有重要的应用研究价值。     

芳香族化合物的清洁催化硝化

综述了芳香族化合物清洁催化硝化体系中硝化剂和催化剂的研究近况,主要介绍了氮氧化物、硝酸和硝酸/乙酸酐三种硝化剂及相应的催化剂体系的催化硝化性能及优缺点,并进一步探讨了清洁硝化的发展前景。     

GAP/CL-20-Based Compound Explosive: A New Booster Formulation Used in a Small-Sized Initiation Network

With ε-2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and glycidyl azide polymer (GAP) as the solid filler and binder, respectively, GAP/CL-20-based compound explosives were designed and prepared. Using micro injection charge technology, the compound explosives were packed into small grooves to explore their application in a small-sized initiation network. The detonation reliability, detonation velocity, mechanical sensitivity, shock sensitivity, and brisance of the explosive were measured and analyzed. The results show that when the solid content of CL-20 is 82 wt%, the explosive charged in the groove has a smooth surface from a macroscopic view. From a microscopic view, a coarse surface is bonded with many CL-20 particles by GAP binder. The GAP/CL-20-based explosive charge successfully generates detonation waves in a groove larger than 0.6 mm × 0.6 mm. When the charge density in the groove is 1.68 g·cm^?3 (90% theoretical maximum density), the detonation velocity reaches 7,290 m·s^?1. Moreover, this kind of explosive is characterized by low impact and shock sensitivity.     

Massive Preparation of Reduced-Sensitivity Nano CL-20 and Its Characterization

Nano 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) was produced massively by ball milling. One thousand grams of the raw CL-20 were used per batch. The product was characterized using laser granularity measurement, scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). The results show that the pulverized particles were pseudo-spheres with an average particle size (d₅₀) of 200 nm, and the thermal decomposition peak temperature of the nano CL-20 was 239.61°C lower than that of the micrometer-sized CL-20 at a heating rate of 15°C · min^?1. Furthermore, compared with the raw CL-20, the impact and friction sensitivities of the nano CL-20 were considerably reduced by 116.2 and 22%, respectively, indicating the great improvement in safety of CL-20.     

2-甲基-5-硝基咪唑合成工艺改进

在 2甲基咪唑用硝酸和硫酸进行消化的过程中 ,通过加入 5%尿素和 50 %硫酸铵作为助剂 ,即消除了原工艺反应过程中有大量氧化氮毒气冒出的现象 ,又提高了收率。在硝化过程中 ,将通常的硫酸和硝酸作为混酸一起加入的方法改为先将硝酸和原料混合 ,然后滴加浓硫酸。改善了反应的再现性和易操作性。在综合优化的条件下 ,收率提高到 90 .7% ,含量为 99.5%。     

Application of Liquid Paraffin in Castable CL-20-Based PBX

Hydroxy-terminated polybutadiene (HTPB)/CL-20 castable explosives plasticized with liquid paraffin were processed successfully by a cast-curing method. The compatibility of liquid paraffin with CL-20, influence of liquid paraffin on CL-20 phase transition, and viscosity of the cast mixture were tested and analyzed. The thermal decomposition characteristics, thermal stability, mechanical sensitivity, and velocity of detonation (VOD) of the HTPB/CL-20 plastic-bonded explosives (PBXs) were also measured. The experimental results showed that liquid paraffin was well compatible with CL-20, and it did not have a distinct effect on the ?- to γ-phase transition of CL-20. In addition, the casting mixture was free-flowing with sufficiently low viscosity. When the content of CL-20 is 90% by weight, the measured VOD reached 8,775 m/s (density of 1.78 g/cm³), and the PBXs exhibited moderate mechanical sensitivity and good thermal stability.     

1-methyl-2,4,5-trinitroimidazole (MTNI), a melt-cast explosive: synthesis and studies on thermal behavior in presence of explosive ingredients

ABSTRACT

Traditionally, TNT based melt-castable explosives have been used till date. Recently, energetics communities are looking for an alternate to TNT in melt-cast formulation because of its toxicity and environmental concerns. 1-Methyl-2,4,5-trinitroimidazole (MTNI) is an insensitive high energy material and potential for use as a melt-cast high explosive formulations in place of TNT. MTNI has superior explosive performance as compared to that of TNT. Typically MTNI is synthesized starting from imidazole by step-wise nitration using strong nitric acid mixture followed by N-methylation offers poor yield. The key step involves during synthesis of MTNI is substitution of third nitro group at fifth position of 2,4-dinitroimidaziole which is limiting for its large-scale preparation. We report herein, an improved method for synthesis of MTNI from 1-methyl-2,4-Dinitroimidazole (MDNI) under different nitration conditions in good yield. Heteropoly acid (HPA) is an efficient, mild and green catalysts used as nitric acid activator. The synthesized MTNI by this method was characterized by FT-IR, NMR & elemental analysis. Thermal behavior of MTNI was determined by differential scanning calorimeter (DSC), thermogravimetric analysis (TGA) and ignition temperature tester. Further, the effects of thermal energy on decomposition of formulations containing MTNI with solid high explosives such as RDX & CL-20 or polymeric binders like HTPB & GAP were investigated. Thermal decomposition mechanisms of MTNI and its precursor, MDNI based on Pyrolysis-GC/MS analysis were also described.     

Preparation and characterization of spherical submicron ε-CL-20 via green mechanical demulsification

ABSTRACT

This report has developed a facile “green mechanical demulsification technology” which can emulsify submicron CL-20 particles greenly and submicron ε-CL-20 particles with stable crystal structure and favorable morphology were successfully prepared by this means. Simultaneously, CL-20 was also refined by spray recrystallization method and jet recrystallization method for better comparison. Structural characterizations and thermal stability of the composites were systematically studied by scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential scanning calorimeter (DSC). Moreover, the safety performance was analyzed by qualitative testing of impact sensitivity and friction sensitivity. Compared with the raw CL-20, submicron CL-20 particles fabricated via the green mechanical demulsification technique were compact spheres with ε-CL-20 crystal form. The CL-20 refined by the spray recrystallization method and the spray recrystallization method exhibited irregular blocky structure and agglomerated needle-like structure, respectively. And the crystal forms of both CL-20 particles were converted from ε-CL-20 to β-CL-20. The activation energy of CL-20 refined via green mechanical demulsification technology was increased from 179.42 kJ/mol to 198.40 kJ/mol, thus enhancing the thermal stability. However, the thermal stability of the refined β-CL-20 showed a distinct decrease due to the transformation of the crystal structure. More importantly, the refined CL-20 particles possessed much lower impact sensitivity. The proposal of green mechanical demulsification method has availably settled the problems that the CL-20, with irregular morphology, is prone to crystal transformation, agglomeration, and environmental pollution. And there is a significant possibility that it is a promising green technology with comprehensive application foreground.     

金属氧化物催化苯液相硝化合成硝基苯

对采用金属氧化物催化剂催化苯液相硝化合成硝基苯的清洁生产工艺进行了研究。以质量分数65%～68%的硝酸为硝化剂,考察了各种金属氧化物催化剂对苯液相硝化反应的催化活性,探讨了反应条件对硝基苯收率的影响和金属氧化物催化剂的重复使用性能。实验结果表明,对于苯液相硝化反应,两性金属氧化物催化剂(MnO2,SnO2,TiO2,ZrO2,CeO2)和酸性金属氧化物催化剂(Sb2O3)较碱性金属氧化物催化剂(ThO2,Co2O3,Bi2O3)的活性高,其中,SnO2催化剂的活性最高。在SnO2催化剂用量0.50g、硝酸与苯的体积比为2.5、反应温度90℃、反应时间7h的条件下,硝基苯收率可达94.88%,硝基苯的选择性为100%。SnO催化剂重复使用3次后活性变化不大。     

浓硫酸/正庚烷乳化液稳定性的研究

利用Turbiscan Lab分散稳定性分析仪,研究了烃相与浓硫酸乳化液的稳定性能,考察了新硫酸和废酸、搅拌时间、搅拌速率、酸烃比及烃种类对乳化液稳定性的影响。结果表明：使用新的浓硫酸与正庚烷混合时,仅能使少量的正庚烷分散到浓硫酸中,使用废酸可完全将正庚烷乳化分散到废硫酸中;酸烃乳化液达到平衡时,增加搅拌时间对浓硫酸和正庚烷乳化液的影响较小,而搅拌速率越高,酸烃比越大,得到的酸烃乳化液也越稳定;不同烃相与浓硫酸形成的乳化液的稳定性不同,其中异辛烷和浓硫酸形成乳化液的稳定性最好,石油醚次之,而正庚烷和浓硫酸形成乳化液的稳定性最差。     

甲基丙烯酸1,1,5-三氢全氟戊酯的合成

在吩噻嗪和硫酸存在下,采用甲基丙烯酸和八氟戊醇直接酯化的方法研究了甲基丙烯酸1,1,5 三氢全氟戊酯的合成。讨论了硫酸的用量、反应物配比、反应温度和反应时间对产物收率的影响。并讨论了以无水硫酸钠为脱水剂时,对产物收率的影响。     

Composition and sorption properties of asphaltene sulfonates

The sulfonation of the dissolved oil objects by concentrated sulfuric acid was carried out at 60, 80, 100 ^oC and the resulting products with a structural-group composition similar to sulfonated asphaltenes were obtained. Structural-group composition of sulfonated oil products was established by Fourier transform infrared spectroscopy and the relative contents of sulfo-, sulfono- and carboxyl ionogenic functional groups was determined on the basis of spectral coefficients. The sorption capacity of sulfonated oil products (10-13 mg/g for Ca²⁺ and 14–18 mg/g for Cu²⁺) was determined by atom-absorption spectroscopy. It was established that the sorption characteristics of sulfonated oil products are determined by the total contents of asphaltene-resin components in starting oil objects and temperature of the sulfonation process.     

柴油吸附脱硫活性炭改性吸附剂研究

研究了用不同金属离子以及糠醛、糠醇、浓硫酸、浓硝酸对活性炭进行改性对活性炭吸附剂对FCC柴油和由正癸烷和二苯并噻吩(DBT)组成的模拟柴油的脱硫率的影响。实验结果表明:金属离子改性中Fe离子改性活性炭脱硫率好;活性炭浸涂糠醛、糠醇也可以提高吸附脱硫性能;浓硫酸、浓硝酸氧化可以增加活性炭表面酸性基团的量,改进脱硫性能,浓硫酸优于浓硝酸。进行了活性炭复合改性实验,结果表明,浓硫酸氧化后再进行Fe改性,脱硫率最高,吸附DBT模型物的脱硫率可达到100%。     

甲醛与二甲苯合成二(二甲苯基)甲烷的研究——缩合反应催化剂

研究了硫酸、苯基磺酸、杂多酸、分子筛等９种催化剂对甲醛与二甲苯缩合反应的催化性能。结果表明，浓硫酸和苯基磺酸具有较高的催化活性，而且单位硫酸的产品产率高。对浓硫酸催化体系的组成、再生方法也进行了探索。     

5,6-二羟基吲哚的合成

以3,4-二甲氧基苯乙腈为主要原料,经去甲基、羟基保护、硝化及还原环合四步反应合成了5,6-二羟基吲哚。去甲基反应中,以氯化氢／吡啶为醚键裂解试剂,收率为90．2%;以氯化苄为羟基保护试剂、碳酸钾为缚酸剂,保护羟基的反应收率为87．8％;浓硝酸硝化的收率为86．9％;还原环合时,10％Pd／C是适宜的催化剂,环己稀作为氢供体,环合收率为85．2%。以3,4-二甲氧基苯乙腈计产物5,6-二羟基吲哚的综合收率为58.6％,所得产物结构经1H NMR分析确认。