稀土氧化钐上甲烷氧化偶联反应的FT—IR研究

用傅里哀变换红外(FT-IR)光谱原位考察了稀土氧化钐上甲烷氧化偶联反应及乙烯,乙烷的氧化反应。在700℃以下,甲烷,乙烯和乙烷分别与氧化钐表面反应时,除检测到表面碳酸基外,未观察到其它表面物种。这些表面碳酸基物种只有在700℃以上才大部分脱附,在氧存在下,高于700℃时这些低碳烃的完全氧化很显著,但在内循环反应体系中发现过量的气相CO_2可抑制烃类的深度氧化。甲烷的偶联反应在700℃以上才可明显观察到。而大部分表面碳酸基也在700℃以上才脱附,但经脱碳酸基或高温氧化处理后的氧化钐上均未明显观察到O~-物种的ESR峰。本文认为经高温脱碳酸基后形成的表面配位不饱和氧物种O~(δ-)(1<δ<2)在甲烷氧化偶联反应中起主要作用。     

La-Ba-Sm体系催化剂上的甲烷氧化偶联

用甲烷氧化偶联反应评价了不同方法制备的Ｌａ－Ｂａ－Ｓｍ体系催化剂，结果表明，用机械混合Ｌａ２Ｏ３，Ｂａ（ＯＨ）２．８Ｈ２Ｏ和Ｓｍ２Ｏ３三组分及高温焙烧方法制备的催化剂，从Ｃ２收率和选择性总体看，较其它方式优越，在催化剂（ＩＶ）上进行了５００ｈ的稳定性实验，在整个过程中，催化剂的活性和选择性基本稳定；催化剂的起动温度较低，在较宽的温度范围内易于控制对工业生产意义较大，通过ＸＲＤ，ＸＰＳ，ＩＲ，ＳＥＭ     

ABO3,A2BO4型复合氧化物催化剂用于CO,CH4,NH3完全氧化的比较

本文探讨了ＣＯ，ＣＨ４和ＮＨ３在ＬａＮｉＯ３，Ｌａ２ＮｉＯ４和ＬａＳｒＮｉＯ４三个催化剂上的氧化行为，并得出结论：对于ＣＯ氧化，关键步骤在于ＣＯ在催化剂表面上的络合活化。Ｎｉ＾３＋含量越高，越利于ＣＯ的络合活化。对于氨氧化，催化反应遵循氧化－还原机理。Ｎｉ＾３＋是主要的活性离子，晶格氧是主要活性氧种。对于ＣＨ４氧化，催化机理较复杂，只是发现Ａ２ＢＯ４型氧化物（Ｌａ２ＮｉＯ４，ＬａＳｒＮｉＯ４）比Ａ     

甲苯选择性氧化制苯甲醛：铁锑氧化物表面性质与催化性能的研究

甲苯选择性氧化制苯甲醛——铁锑氧化物表面性质与催化性能的研究葛欣张惠良（南京大学化学系南京２１００９３）关键词铁锑氧化苯甲醚甲苯选择性氧化中图分类号Ｏ６４３．３２２铁锑氧化物是烯烃氧化反应中催化剂的主要组成之一［１］，在催化剂中当Ｓｂ／Ｆｅ从１．０变...     

O2选择氧化烷烃新进展

综述了９０年代以来有关金属络合物催化Ｏ２选择氧化烷烃研究的进展,如：卤人卟啉铁络合物在无还原剂上催化烷烃羟基化,尖林金属络合物催化烷烃氧化及高分子或固载化金属络合物的催化性能。     

甲烷部分氧化制合成气：Ⅱ.载体的影响

本文对三种催化剂（１％Ｒｈ／ｍ－Ｓｍ２Ｏ３，１％Ｒｈ／ｃ－Ｓｍ２Ｏ３）在甲烷部分氧化反应的催化活性与一氧化碳和氢的选择性作了比较。用二氧化碳的程序升温脱附测试了载体的相对碱性强弱；并用同位素交换反应测定了载体和负载型铑催化剂对甲烷分子中Ｃ－Ｈ和氧气分子中Ｏ－Ｏ键的解离活化能力，虽然催化活性高低与载体的碱性及解离活化能力之间没有直接的对应关系，但通过载体对反应活性影响的研究能揭示一般的规律，对研制甲     

苯酚在热氧化法制备的SnO2/Ti电极上的电氧化研究

以热氧化法制备的ＳｎＯ２／Ｔｉ电极作为阳极用于含苯酚酸性溶液的恒电流电解,测定了苯酚浓度、溶液中化学需氧量（ＣＯＤ）以及瞬时电流效率等随电解时间的变化。结果表明,用ＳｎＯ２／Ｔｉ电极代替铂作为阳极可使相同氧化电量下的ＣＯＤ明显下降,而平均电流效率提高了３倍,讨论了两种电极上苯酚氧化的反应机理。     

难降解有机废水的催化氧化法处理

催化氧化法可通过多种途径来加强传统的化学法处理效果，目前已成为难降解有机废水处理的一项重要新技术。本文介绍了光催化氧化法、均相氧化法、多相氧化法(包括电催化氧化法)以及超临界水氧化技术的国内外研究现状及特点，并对其在有机废水中的应用情况和发展前景作了扼要评述。     

萃取色谱分离—原子发射光谱测定超高纯氧化铥,氧化镱和氧化镥中痕…

用２－乙基己基膦酸单２乙基己酯萃取色说分离－原子发射光谱测定超高纯Ｔｍ２Ｏ３，Ｙｂ２Ｏ３，Ｌｕ２Ｏ３中痕量稀土杂质，可用于纯度为９９．９９９９％－９９．９９９９９％Ｔｍ２Ｏ３，Ｙｂ２Ｏ３，ｌＵ２ｏ３的纯分分析，１４个稀土杂质的回收率在６７％－１３３％之间；相对标准偏差５．１％－２３．２％，分离周期１０－１３ｈ。     

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.