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。     

SO42-/TiO2固体超强酸催化甲苯硝化的研究

以固体超强酸S04^2-／TiO2为催化剂、浓硝酸为硝化剂对甲苯进行硝化，探索了不同条件下催化剂对甲苯转化率和硝化定位的影响。结果表明，在催化剂用量为硝酸质量的10％，反应温度55℃，反应时间3h，以硝酸质量l％的浓硫酸作底酸的最佳条件下，甲苯转化率达81％，邻硝基甲苯与对硝基甲苯之比为O．91。催化剂可以通过焙烧再生。     

SO_4~(2-)/TiO_2固体超强酸催化甲苯硝化的研究

以固体超强酸SO_4~(2-)/TiO_2为催化剂、浓硝酸为硝化剂对甲苯进行硝化,探索了不同条件下催化剂对甲苯转化率和硝化定位的影响。结果表明,在催化剂用量为硝酸质量的10％,反应温度55℃,反应时间3h,以硝酸质量1％的浓硫酸作底酸的最佳条件下,甲苯转化率达81％,邻硝基甲苯与对硝基甲苯之比为0.91。催化剂可以通过焙烧再生。     

沸石固体酸催化苯硝基化研究

以硝酸为硝化剂,自制沸石固体酸为催化剂,进行了硝基苯合成新工艺的研究,优化的反应条件为：常压８０～１００℃、反应时间３ｈ,硝酸／苯（体积比）１．５～３．５时,硝基苯收率＞９６％。     

静态混合管式绝热硝化制备一硝基甲苯工艺研究

利用静态混合管式绝热反应装置,以甲苯为原料,硝酸为硝化剂,硫酸为催化剂,连续制备一硝基甲苯。利用相应面法优化混酸组成,通过单因素实验考察了影响因素,利用正交实验优化了工艺条件,适宜工艺条件为:初始温度50℃,硝酸比1.1∶1,流速0.04m/s,停留时间5min,混酸组成为w(硫酸)=68%,w(硝酸)=12%,w(水)=20%,在该工艺条件下甲苯单程转化率94.5%,一硝基甲苯产率可达88.9%。与传统硝化工艺相比,反应时间大大缩短,反应条件温和,安全性高,环境污染减少,反应热可用来浓缩混酸。     

负载型磷钨酸催化苯气相硝化

研究了负载型磷钨酸对苯气相硝化反应的催化活性 ,探讨了载体、反应温度、杂多酸负载量、苯 硝酸摩尔比对硝化率的影响。试验表明 ,H3PW1 2 O40 SiO2 催化剂对苯气相硝化反应具有很好的催化活性 ,在苯 硝酸摩尔比为 2、反应温度 15 5～ 16 0℃时 ,硝基苯产率可达 90 6 %     

负载型杂多酸催化苯硝化反应研究

制备了3种 Keggin 型杂多酸,利用 IR 对其结构进行了表征,并对其催化苯液相硝化反应的性能进行了研究。采用等体积浸渍法制备了负载型磷钨杂多酸催化剂,考察了 SiO_2、活性炭、5A 分子筛、γ-Al_2O_3等载体对其催化性能的影响,以及催化剂的重复使用效果。结果表明,SiO_2负载的磷钨杂多酸催化剂具有较好的催化活性,在 V(苯)/V(硝酸)=1:3(摩尔比为1:3.5),反应温度75℃,反应时间3 h,负载型催化剂用量占总反应原料质量2%的条件下,硝基苯的收率为60.6%。     

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。     

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。     

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。     

Heteropolyacids: An Efficient Catalyst for Synthesis of CL-20

CL-20, a high-energy material with a cage-like structure, is considered the most powerful explosive today. It is usually prepared via nitration with concentrated nitric and sulfuric acid, but this technique pollutes the environment. In this article, CL-20 was synthesized by nitration of 2,6,8,12-tetraacetyl 2,4,6,8,10,12-hexaazatetracyclo[5,5,0,0^3,11,0^5,9]dodecane (TAIW) using a clean nitrating agent, heteropolyacids. Using the new nitrating agent caused the elimination of concentrated sulfuric acid during the reaction. This is an environmentally friendly technique.     

硝酸氧化蒽制备蒽醌

研究了硝酸存在下蒽的氧化反应，并考察了反应时间、反应温度、硝酸的浓度和催化剂等因素对蒽醌收率的影响。在优化的实验条件下，获得了８２．５％的收率。该法条件温和，步骤简单，实为一种简便制备蒽醌的方法，而且具有一定的工业应用前景。     

酸处理铌酸催化模拟汽油氧化脱硫的研究

以二苯并噻吩的异辛烷溶液为模拟油、过氧化氢为氧化剂,在密闭钢制反应釜反应器中,考察了水洗铌酸、硝酸处理铌酸、硝酸及磷酸处理铌酸为催化剂的催化氧化脱硫性能。结果表明,硝酸及磷酸处理铌酸催化剂具有较高的催化活性和再生性能,在催化剂用量为5%、反应温度为60 ℃、反应时间为3 h、氧化剂H2O2与硫摩尔比为3、剂油体积比为1时,脱硫率可达96.34%。     

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.     

固体酸催化烯烃叠合技术研究进展

随着我国炼油工艺和汽油池结构的不断调整,通过烯烃叠合反应将C4烯烃转化为高辛烷值清洁汽油组分的技术得到快速发展,其中固体酸催化剂在烯烃叠合技术工艺中应用最广泛。简单介绍烯烃叠合技术原料来源及加工路径,总结目前应用广泛的各类固体酸催化剂使用情况,主要包括固体磷酸、酸性树脂、分子筛、白土、杂多酸、磺化金属氧化物以及金属/酸载体负载型催化剂等,结合固体酸催化剂反应机理发现,分子筛催化剂由于孔道和酸性可调、易再生、无污染、活性高等特点,具备广阔的市场应用前景。     

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.     

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。