在La改性HZSM-5分子筛上甲醇对噻吩转化反应规律的影响

探讨了在HZSM-5(硅铝摩尔比为25)分子筛催化剂上,甲醇对噻吩在固定床微型反应器中催化脱硫转化反应规律的影响.研究结果表明:反应温度只有达到623 K时,噻吩才有较大的转化反应,此时噻吩转化率达到了51%以上;含活性氢物质甲醇的浓度是甲醇与溶剂苯的体积比为1∶2;掺镧的HZSM-5催化剂对噻吩的催化转化有较大的促进作用,掺镧量为1.0%时噻吩的转化率和硫化氢的产率分别达到了51.3%、18.1%,与未掺镧的HZSM-5分子筛催化剂相比,噻吩的转化率和硫化氢的产率分别提高了36.0%、11.9%;质量空速对噻吩催化转化的影响主要体现在影响噻吩在催化床层上的停留时间,质量空速为14.h-1比较合适.     

芳胺常压气相N—烷基化反应研究

在固定床催化反应器中常压下研究了芳胺和醇的气相法Ｎ－烷基化反应。考察了γ－Ａｌ２Ｏ３系列催化剂的反应性能，筛选出了两种适用于苯胺Ｎ－甲基化反应且性能较好的催化剂。反应条件为：在甲醇和苯胺的摩尔比为３：１时，反应温度为２８０℃，液时空速为０．３ｈ＾－１的条件下，苯胺转化率为９９％，生成Ｎ，Ｎ－二甲基苯胺（ＤＭＡ）的选择性为９２％。研究了甲醇和芳环上不同位置取代的甲基苯胺的反应规律，其转化率顺序：苯胺     

铜 基 催 化 剂 上 甲 醇 水 蒸 汽 重 整 制 氢Ⅰ． 催 化 剂 组 成 的 影 响

在H2O/CH3OH摩尔比为1.3、液空速为1.5h-1、反应温度为220℃条件下,对甲醇水蒸汽重整制氢Cu/Zn/(Fe,Mn,Cr)/AlO催化剂性能进行了考察.研究表明,Cr的加入可以显著提高甲醇的转化率,降低出口气体中的CO含量.与Cu60Zn30Al10催化剂相比,Cu30Zn15Cr45Al10催化剂出口气体中CO的含量降低54%,甲醇的转化率提高约20%.     

分子筛选择催化合成N，N—二甲基苯胺（DMA）

本文报道在改性的ZSM－5分子筛催化剂上，苯胺和甲醇的气相甲基化反主尖，研究发现，在300℃和常压下，液时空速为1.0h^-1和苯胺／甲醇摩尔比为1／3的条件下，改性的ZSM－5催化剂对DMA贩选择率为88.5％，苯胺转化率为97.8％，此结果有明显的应用前景。     

芳胺常压气相N－烷基化反应研究

在固定床催化反应器中常压下研究了芳胺和醇的气相法Ｎ－烷基化反应。考察了γ－Ａｌ２Ｏ３系列催化剂的反应性能，筛选出了两种适用于苯胺Ｎ－甲基化反应且性能较好的催化剂。反应条件为：在甲醇和苯胺的摩尔比为３１时，反应温度为２８０℃，液时空速为０．３ｈ－１的条件下，苯胺转化率为９９％，生成Ｎ，Ｎ－二甲基苯胺（ＤＭＡ）的选择性为９２％。研究了甲醇和芳环上不同位置取代的甲基苯胺的反应规律，其转化率顺序：苯胺≈对一甲苯胺≈间－甲苯胺＞邻－甲苯胺。从Ｃ１到Ｃ４不同结构的醇和苯胺反应的规律研究，证明随醇中碳原子数目的增加，醇的反应活性降低，正构醇和苯胺反应和异构醇与苯胺反应随温度升高的变化趋势相反。     

甲醇水蒸气重整制氢CuO/CeO2-ZrO2/SiC整体催化剂的研究

采用浸渍法和溶胶凝胶法制备了CuO/CeO₂-ZrO₂/SiC整体催化剂，并将其用于甲醇水蒸气重整制氢反应中。结果表明，与CuO/CeO₂-ZrO₂颗粒催化剂相比，CuO/CeO₂-ZrO₂/SiC整体催化剂催化活性较好，产氢速率较快且重整气中CO体积分数较低。进一步探究了涂层涂覆量和CuO负载量对催化性能的影响，结果表明，当CeO₂-ZrO₂复合氧化物涂层涂覆量在15%±1%，CuO负载量为5%±1%时，催化性能较好；当反应温度为340℃，水醇物质的量比为1.2，甲醇水蒸气气体空速为4840 h^-1时，甲醇转化率为86.0%，产氢速率为1490.0 L/（m³·s），重整气中CO体积分数为1.55%。最后通过单因素实验法探究了甲醇水蒸气气体空速、水醇物质的量比和反应温度对反应的影响。结果表明，随着气体空速变大，甲醇转化率下降，产氢速率上升，重整气中CO体积分数下降。随着水醇物质的量比增加，甲醇转化率先上升后下降，产氢速率先上升后下降，重整气中CO体积分数下降。随着反应温度的升高，甲醇转化率、产氢速率和重整气中CO体积分数均上升。     

负载型钾盐催化剂用于合成苯甲醚的研究

采用固定床连续进料的反应器代替传统间歇反应釜作为评价反应器,以环境友好的碳酸二甲酯为甲基化试剂,由苯酚合成苯甲醚的反应新工艺。采用SiO2负载的钾盐类催化剂,考察了反应温度、进料空速、原料配比、活性组分负载量以及催化剂用量等对反应性能的影响。研究表明,在该负载型钾盐催化剂上苯酚的转化率均较高,且生成苯甲醚的选择性较好。尤其是在KF/SiO2催化剂上,在DMC/苯酚摩尔比为2∶1,进料空速为2 h-1,反应温度为250℃时,苯甲醚收率和选择性分别高达93.93%和98.19%。而且该负载型催化剂活性比较稳定,未发现活性组分流失,反应运行16 h催化剂未见失活。     

生物质焦油模型化合物催化转化实验研究

以苯和甲苯为焦油的模型化合物,在固定床反应器上研究了堇青石和白云石两种催化剂作用下,温度、蒸汽量和空速对焦油催化转化的影响。结果表明,苯和甲苯的转化率都随温度的提高和空速的降低而升高。在堇青石和白云石催化作用下,甲苯在裂解温度900℃,S/C摩尔比为1.5时转化率最高,转化率均达到95%。苯在裂解温度900℃,S/C摩尔比为1.0时转化率最高,转化率分别为61%和53%。蒸汽量的增大有助于裂解气体成分的调整。堇青石稳定性实验表明,积炭是造成催化剂活性降低的重要原因。     

微型平板式反应器中甲醇水蒸气重整制氢的研究

研制了一种高效平板式微型制氢反应器,将甲醇重整和催化燃烧集于一体,吸热、放热合理耦合,实现快速启动和制氢过程自热运行;在反应器中进行甲醇水蒸气重整实验,考察了反应器腔内的温度分布,以及温度、空速和水醇比对制氢过程的影响。结果表明,当温度为270℃,空速为870h-1,水醇比为1.3时,甲醇转化率最高为94.85%,重整气组成为74.53%H2、1.76%CO、23.71%CO2;累计运行400h,重整最大产氢量接近6000mL/h,可为便携式燃料电池提供稳定氢源。     

金属壁载PdZn/Al2O3/FeCrAl催化剂上甲醇水蒸气重整制氢

研究了金属壁载PdZn/Al2O3/FeCrAl催化剂在不锈钢平板式微型制氢反应器中对甲醇水蒸气重整制氢的催化性能.结果表明,在反应温度为350℃,甲醇GHSV=1·6L/(g·h),水/醇摩尔比为1·2时,甲醇转化率可达100%,H2选择性达99%以上,出口CO含量低于0·5%,同时催化剂具有很好的稳定性.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.