La—Ba—Cu复合氧化物在催化消除NO反应中催化性能的研究

合成了具有钙钛石结构的复合氧化物ＹＢａ２Ｃｕ３Ｏ７、ＬａＢａ２Ｃｕ３Ｏ７、ＬａＢａＣｕ２Ｏ５、Ｌａ２ＢａＣｕ３Ｏ７和Ｌａ４ＢａＣｕ５Ｏ１２。考察了它们对ＮＯ分解和ＮＯ＋ＣＯ反应的催化性能。结合化学分析、ＸＲＤ、ＴＰＤ和ＴＰＲ对催化剂的表征结构，探讨了该系列复合氧化物对ＮＯ分解和ＮＯ＋ＣＯ反应的催化机理。     

CaO／La2O3催化剂上的甲烷氧化偶联反应的研究

研究了不同配比的ＣａＯ／Ｌａ_２Ｏ_３催化剂对甲烷氧化偶联反应的催化性能。适当配比的ＣａＯ／Ｌａ_２Ｏ_３催化剂的性能明显优于纯Ｌａ_２Ｏ_３或ＣａＯ，在钙含量为２４％和８１％（Ｃａ／（ｃａ＋Ｌａ））处，Ｃ_２选择性和Ｃ_２收率分别出现两个峰值。同时还发现，１３％ＣａＯ／Ｌａ_２Ｏ_３样品显示出良好的低温催化性能，在５５０℃反应温度下获得了３１．５％的甲烷转化率和４５％的Ｃ_２选择性。并采用ＸＲＤ、ＸＰＳ和Ｃｏ_２ＴＰＤ等技术研究了催化剂的结构。结果表明，ＣａＯ／Ｌａ_２Ｏ_３体系催化剂上没有检测到新物相产生。但是，催化剂中ＣａＯ与Ｌａ_２Ｏ_３两组分之间存在着相互作用，有利于表面活性中心的形成。     

Ba—La2O3催化剂的表面碱性,活性氧种对甲烷氧化偶联的影响

利用ＣＯ２－ＴＰＤ技术考察了Ｂａ－Ｌａ２Ｏ３系催化剂的表面碱性，实验发现，催化剂表面仅有单一的强碱位或中碱位时，其催化性能均较差。只有表面的中碱位与强碱位以适当量共同存在的样品（６％Ｂａ－Ｌａ２Ｏ３），才能获得好的催化活性和Ｃ２选择性。此碱性特征可能有利于表面活性位的产生。同时利用ＸＲＤ和ＸＰＳ等技术分别对体相结构和表面氧物种进行了研究。结果表明，Ｂａ－Ｌａ２Ｏ３系催化剂表面存在Ｏ２＾２－离子，但     

LaCaMnO3催化剂活性相的结构和形成机理的研究

利用ＴＧ，ＤＴＡ，ＸＲＤ和ＸＰＳ方法研究了Ｌａ０．２Ｃａ０．８ＭｎＯ３催化剂的结构和形成机理。样品用Ｌａ，Ｃａ，Ｍｎ混合硝酸盐制备。随着焙烧温度的升高发生的一系列的固相反应，发现氨氧化催化剂催化活性与生成的ＣａＭｎＯ３含量成正比。在９００℃制备的含有ＣａＭｎＯ３，Ｌａ０．５７５Ｃａ０．４２５ＭｎＯ３，Ｍｎ２Ｏ３和Ｌａ２Ｏ３的混合物是氨氧化最佳催化剂，活性相是ＣａＭｎＯ３，并具有大量的氧空穴。     

甲烷氧化偶联La—Me—O（Me=Mg,Ca,Sr,Ba）系催化剂表面氧种的研究

利用ＣＯ２－ＴＰＤ法考察了Ｌａ－Ｍｅ－Ｏ（Ｍｅ＝Ｍｇ，Ｃａ，Ｓｒ，Ｂａ）系催化剂的表面碱性，并用Ｏ２－ＴＰＤ，Ｃ４－ＴＰＤ法对该体系的表面活性氧种进行了表征，并与催化性能相关联，结果表明，Ｌａ－Ｂａ－Ｏ催化剂由于表面强碱性中心数目多，产生活性氧种的数目也多，有利于甲烷的活性，因而具有最高的甲烷转化率和Ｃ２烃选择性，脉冲反应表明，在无气相氧存在下，表面晶格氧参与了氧化偶联，而且是选择氧化的活性氧种。     

甲烷氧化偶联制乙烯La2O3—BaO体系催化剂稳定性的研究

研究了甲烷氧化偶联制乙烯高选择性Ｌａ２Ｏ３－ＢａＯ体系催化剂的稳定性．在８００℃、ＣＨ４空速１００００ｈ－１、ＣＨ４／Ｏ２＝８．０～８．３的条件下，催化剂稳定运转了５００ｈ，ＣＨ４转化率和Ｃ２选择性分别为≥１８％和≥８０％．ＸＲＤ和ＸＰＳ分析表明，该催化剂物相稳定，表面Ｌａ／Ｂａ原子浓度之比随反应时间的增加而稍有增加，有利于催化剂活性和选择性的稳定．     

NaCl和B2O3在修饰FeOχ催化剂中的协同作用

应用连续催化反应，ＸＰＳ，ＸＲＤ，Ｈ２－ＴＰＲ，Ｏ２－ＴＰＤ和Ｉｎ－ｓｉｔｕ Ｍｏｓｓｂａｕｅｒ谱等方法表征了一系列组成不同的ＮａＣｌ／Ｂ２Ｏ３／Ｆｅ２Ｏ３催化剂。结果表明ＮａＣｌ与Ｂ２Ｏ３在修饰ＦｅＯｘ催化剂上存在明显的协同作用，Ｂ２Ｏ３调变了ＦｅＯｘ的还原能力，ＮａＣｌ修饰了Ｂ２Ｏ３／ＦｅＯｘ使之具有很高的还原速度与晶格氧气化速度。催化剂的催化性能同这种协同作用密切相关。     

掺杂物对负载型ＺｒＯ２／Ａｌ２ Ｏ３的催化性能的影响

用浸渍沉淀法分别制备了负载型ＺｒＯ２／Ａｌ２Ｏ３和ＺｒＯ２（ＭｇＯ、Ｋ２Ｏ、ＣｅＯ２、Ｌａ２Ｏ３）／Ａｌ２Ｏ３催化剂．用ＸＲＤ、ＢＥＴ、ＴＰＤ对催化剂的晶相结构、比表面积、孔径分布、表面酸碱性等进行了表征;同时以ＣＯ２和ＣＨ３ＯＨ为探针用原位红外对催化剂的吸附行为进行研究．结果表明,掺杂氧化物有效的阻止ＺｒＯ２晶粒的团聚,并提高了催化剂的比表面积和平均孔径;ＣｅＯ２的添加有利于碱性中心数的增多,Ｌａ２Ｏ３有利于酸性中心数的提高．原位红外结果表明ＣＨ３ＯＨ能在ＺｒＯ２（ＣｅＯ２、Ｌａ２Ｏ３）／Ａｌ２Ｏ３催化剂表面发生解离吸附,而ＣＯ２在催化剂表面均出现单齿态吸附．ＣＯ２和ＣＨ３ＯＨ在常压下直接合成碳酸二甲酯（ＤＭＣ）反应中ＺｒＯ２（ＣｅＯ２、Ｌａ２Ｏ３）／Ａｌ２Ｏ３催化剂表现出较好的催化活性和选择性．     

ROLE OF Ga AND Pt-Ga IN THE CONVERSION OF PROPANE OVER Ga/HZSM-5 AND Pt-Ga/HZSM-5

为获得较高的Ｃ２选择性，在加水（水蒸气）条件下，研究了添加ＣａＯ对甲烷氧化偶联Ｌａ２Ｏ３催化剂的影响。发现ＣａＯ的添加提高了Ｌａ２Ｏ３催化剂的活性，同时水的添加明显地提高了催化剂的Ｃ２选择性。在加水条件下，Ｌａ２Ｏ３－ＣａＯ催化剂获得了较好的结果，其ＣＨ４转换率为２０％，Ｃ２选择性超过８０％。利用ＸＲＤ和ＸＰＳ技术对催化剂进行了表征，并对加水和不加水条件下的催化剂性能与结构变化的关系进行了讨论     

镧助剂对Fe/ZrO2催化剂结构及F-T反应性能的影响

用ＸＲＤ，Ｍｏｓｓｂａｕｅｒ谱，ＴＰＲ，ＣＯ－ＴＰＤ和ＣＯ加氢反应性能测试等手段研究了镧助剂对Ｆｅ／ＺｒＯ２催化剂结构及Ｆ－Ｔ合成催化剂性能的影响。结果表明，不同的制备方法明显影响催化剂的结构及反应的性能，镧助剂以Ｌａ２Ｏ３形式存在时，催化剂上甲烷选择降低，烯烃选择性提高；镧助剂以ＬａＦｅＯ３形式存在时，催化剂的催化活性大大提高，但同时甲烷选择性上升，烯烃选择性下降。     

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.