低碳烷烃合成芳烃的研究

对ＺＳＭ－５型高硅沸石进行了锌改性，制备了不同锌含量的Ｚｎ／ＨＺＳＭ－５催化剂。以丙烷为原料，在反应温度４７０～５５０℃，空速１～７ｈ￣（－１）条件下反应，并考察了催化剂的稳定性。结果表明，Ｚｎ／ＨＺＳＭ－５较ＨＺＳＭ－５在原料转化率变化不大的情况下，芳烃选择性有较大提高，液体产物收率明显增加。氨ＴＰＤ和吡啶陡吸附红外光谱表明，Ｚｎ／ＨＺＳＭ－５较ＨＺＳＭ－５总酸量低，Ｌ酸量多，Ｂ酸量少。丙烷在线热重分析表明，Ｚｎ／ＨＺＳＭ－５积炭初速度较ＨＺＳＭ－５低一半，Ｈ＿２化学吸附表明，Ｚｎ／ＨＺＳＭ－５的吸氢量是０．４５ｍｍｏｌＨ２／ｇＺｎ，相当于每ｍｇ锌可吸附２．７１×１０￣（１７）个氢分子。     

低碳烷烃合成芳烃的研究：Ⅱ.Zn—HZSM—5催化剂上丙烷的转化

对ＺＳＭ－５型高硅沸石进行了锌改性，制备了不同锌含量的Ｚｎ／ＨＺＳＭ－５催化剂。以丙烯为原料，在反应温度４７０￣５５０℃，空速１￣７ｈ＾－１条件下反应，并考察了催化剂的稳定性。结果表明，Ｚｎ／ＨＺＳＭ－５较ＨＺＳＭ－５在原料转化率变化不大的情况下，芳烃选择性有较大提高，液体产物收率明显增加。氨ＴＰＤ和吡啶吸附红外光谱表明，Ｚｎ／ＨＺＳＭ－５较ＨＺＳＭ－５总酸量低，Ｌ酸量多，Ｂ酸量少。丙烷在线热重分     

Ni改性Mo／HZSM－5催化剂上甲烷芳构化性能研究

Ｎｉ改性Ｍｏ／ＨＺＳＭ－５催化剂上甲烷芳构化性能研究王冬杰，张一平，费金华，郑小明（杭州大学催化研究所，杭州，３１００２８）关键词甲烷，Ｍｏ－Ｎｉ／ＨＺＳＭ－５催化剂，芳构化，芳烃由于甲烷氧化偶联和部分氧化遇到了转化率和选择性不易兼顾及甲烷深度氧化难...     

^27Al MASNMR研究改良HZSM—5结构热稳定性

使用固体高分辨＾２７Ａｌ ＭＡＳＮＭＲ技术研究了改良ＨＺＳＭ－５分子筛在不同预处理条件及催化反应与再生时结构热稳定性。结果表明，预处理条件对ＨＺＳＭ－５骨架的热稳定性有着明显影响。骨架脱顺序为：水热处理＞热处理；ＧａＨＺＳＭ－５＞ＨＺＳＭ－５ＨＺＳＭ－５＞＞ＺｎＨＺＳＭ－５。水热处理样品ＨＺＳＭ－５，ＧａＨＺＳＭ－５在反应后非骨架铝重新迁入了沸石骨架，即存在“反应补铝”效应。     

甲烷在过渡金属离子交换分子筛催化剂上的无氧芳构化

考察了以第四周期过渡金属离子交换改性的ＨＺＳＭ－５为载体的催化剂上甲烷的无氧芳构化性能，并与反应后催化剂上的积炭量进行了关联。过渡金属离子引入ＨＺＳＭ－５的交换位后，起到了助剂作用，抵制了积炭的生成，从而使得催化剂的甲烷芳构化活性和稳定性均得到不同程度的提高，其中以Ｃｕ＾２＋、Ｆｅ＾３＾＋，ＶＯ＾２＋和Ｍｎ＾２＋离子交换改性的ＭｏＯ３／Ｍ－ＨＺＳＭ－５催化剂的活性和稳定性较高。     

EFFECT OF CATALYST CONCENTRATION ON CATALYTIC PERFORMANCE IN LIQUID PHASE DIMETHYL ETHER SYNTHESIS FROM SYNGAS

利用ＺＳＭ－５型沸石可将轻烃选择性地转化为苯，甲苯和二甲苯。ＨＺＳＭ－５催化剂上丙烷转化率和芳烃选择性都很低，但在ＨＺＳＭ－５上添加Ｇａ或Ｐｔ－Ｇａ（双金属改性）后丙烷转化率和芳烃选择性都有很大提高。实验结果表明，Ｇａ／ＨＺＳＭ－５催化剂经氢气高温预处理后，其上的Ｂｒｏ．．ｎｓｔｅｄ酸中心数目减少。铂的加入促进了镓物种的还原，而还原的镓物种可以中和相当一部分催化剂表面Ｂｒ．ｎｓｔｅｄ酸中心，然后形成高度不饱和的催化活性中心。这些中心可以作为Ｌｅｗｉｓ中心，从丙烷和反应中间产物中拔除Ｈ－，使丙烷高选择性地生成芳烃     

Zn改性HZSM－5沸石上甲醇的转化反应

Ｚｎ改性ＨＺＳＭ┐５沸石上甲醇的转化反应周钰明（东南大学化学化工系，南京２１００９６）韩刚丁莹如（南京大学化学系，南京２１００９３）关键词ＨＺＳＭ－５沸石，锌，改性，甲醇，汽油用合成气合成汽油的二段法发展较快［１］．由于合成甲醇技术在工业上是成熟的，...     

氟氯有机化合物对HZSM-5分子筛改性过程中氟和氯的作用

利用ＸＲＤ，ＭＡＳ，ＮＭＲ，ＩＲ和ＸＰＳ等手段研究了ＣＦ４－ｎＣｌｎ改性的ＨＺＳＭ－５分子筛的体相和表面结构的变化。结果表明，改性过程中Ｆ和Ｃｌ均能使ＨＺＳＭ－５脱铝和脱硅。Ｃｌ可以使沸石骨架ＳｉＯ２／Ａｌ２Ｏ３升高，而Ｆ除使沸石骨架脱铝外，还会极化其晶格。Ｆ比Ｃｌ更容易在沸石表面富集。Ｆ和Ｃｌ是通过取代Ｏ或ＯＨ与沸石表面Ｓｉ或Ａｌ作用的。改性后的沸石表面有数种含氟表面物种存在。     

P-HZSM-5催化剂上合成对异丙基苯酚的研究

研究了在Ｐ－ＨＺＳＭ－５ 上苯酚与异丙醇烷基化合成对异丙基苯酚（ｐ－ＩＰＰ）的反应, 考察了磷含量对催化反应性能的影响, 用ＮＨ３－ＴＰＤ和Ｐｙｒ－ＩＲ表征了Ｐ－ＨＺＳＭ－５ 的表面酸性质． 结果表明, 磷改性ＨＺＳＭ－５ 可提高ｐ－ＩＰＰ选择性（达９５％ ）, 而降低了苯酚的转化率, 并导致酸量减少和酸强度减弱． 磷与分子筛的相互作用引起了分子筛脱铝． 焙烧温度对活性和选择性均有影响． 分子筛在９７３ Ｋ、Ｐ－ＨＺＳＭ－５ 在８２３ Ｋ焙烧时, ｐ－ＩＰＰ选择性最高     

FT-IR和程序升温热谱技术研究Mo/HZSM-5催化剂的制备过程

采用ＦＴ－ＲＩ和程序温热谱技术研究了Ｍｏ／ＨＺＳＭ－５催化剂的制备过程。结果表明Ｍｏ／ＨＺＳＭ－５样品在合适的温度下焙烧一定时间，Ｍｏ物种与ＨＺＳＭ－５分子筛的酸中心起作用，并且一部分Ｍｏ物种会迁移到分子筛道内。     

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.