Co掺杂的OMS-2纳米纤维的合成研究

以KMnO4、MnSO4、Co (NO3)2?6H2O和HNO3为反应原料,采用水热法合成了一系列掺杂过渡金属Co的氧化锰八面体分子筛(OMS-2),采用X-射线衍射(XRD),扫描电镜(SEM),傅里叶红外光谱(FT-IR),低温氮气物理吸脱附和H2程序升温还原(H2-TPR)对样品进行了表征,研究了Co的掺杂对OMS-2分子筛的结构、形貌和氧化还原性质等的影响,并对该系列催化剂进行了CO氧化性能评价。结果表明,掺杂的Co并未改变OMS-2的晶体结构,并高分散在OMS-2骨架结构中;掺杂Co的OMS-2分子筛的形貌发生了由纳米短棒向纳米纤维的转变。不仅如此,Co的掺杂增加了活性氧物种的移动性,改善了OMS-2分子筛的催化CO氧化性能。     

Al-Y共掺杂对ZnO纳米棒形成及光催化活性的影响

以Zn(NO3)2·6H2O,Al(NO3)3·9H2O,Y(NO3)3·6H2O和Na OH为原料,采用溶液法制备了Al-Y共掺杂Zn O光催化剂(Al-Y/Zn O),并用X射线衍射(XRD)、扫描电镜(SEM)考察了Al,Y共掺杂对Zn O纳米棒形成及形貌的影响。结果表明,Al-Y共掺杂对Zn O晶粒大小基本没有影响,但会严重抑制Zn O纳米棒的生成,促使碱式硝酸锌(Zn5(OH)8(NO3)2·2H2O)的生成。以甲基橙(MO)为模型污染物考察了Al-Y共掺杂对Zn O纳米棒光催化活性的影响。结果发现,适量的Al-Y共掺杂会显著提高Zn O纳米棒的光催化活性。     

以稀土为连接单元基于Anderson型[Al(OH)6Mo6O18]3-的一维拓展结构的合成及性质研究

在常规条件下合成4个新型的稀土-Anderson型多金属氧酸盐拓展结构化合物(C5H9NO2)2[Ln(H2O)7AlMo6H6O24].11H2O(Ln=La(1),Ce(2),Pr(3),Gd(4);C5H9NO2=脯氨酸),并通过元素分析、红外光谱、紫外可见光谱、热重分析和X射线单晶衍射等方法对化合物晶体结构进行了表征。结构分析表明:以上4个化合物是同构的,均结晶在单斜C2/c空间群。在这些结构中,[Al(OH)6Mo6O18]3-首先通过稀土离子连接形成一维链,相邻的链再进一步通过脯氨酸和结晶水分子的氢键作用形成三维超分子结构化合物。我们以化合物1为代表研究了这类化合物的光催化性能,在紫外光照射下表现出很好的降解RhB(罗丹明B)的光催化性质。     

水热合成掺Fe氧化锌复合材料及其光催化活性

以Zn(Ac)2•2H2O、Fe(NO3)3•9H2O和NaOH为原料,采用水热法合成了Fe掺杂ZnO复合材料。并用x射线衍射和扫描电子显微镜技术对合成样品的结构和形貌进行了表征,Fe掺杂ZnO合成产物为直棒状,直径为500 nm,长度为3 µm左右。样品的紫外可见漫反射分析,在300~500 nm紫外可见光区域均有强的吸收。利用Fe掺杂ZnO作为光催化剂降解有机染料,发现对于光催化降解有机染料有较好的降解功能,且光降解性能优于纯ZnO材料。     

原位合成稳定的Ti~(3+)自修饰介孔TiO_2光催化剂在环境净化中的应用（英文）

半导体光催化剂Ti O2因具有绿色环保无污染、化学稳定性好及可实现稳定产氢等优点而广泛应用于光解水、废水处理和空气净化等领域.然而,锐钛矿相Ti O2禁带宽度约为3.2 e V,仅对紫外光响应.而在太阳光中,44%左右为可见光,紫外光仅占不到4%.为了提高Ti O2对太阳光的利用率和在可见光照射下的光催化活性,近年来人们采用掺杂金属/非金属离子以及与可见光催化剂复合等方法对Ti O2进行改性.但是这些离子掺杂的方法会不可避免地在Ti O2晶格中形成结构缺陷,这些结构缺陷作为光生电子和空穴的复合中心不利于电子和空穴分离.最近研究表明,通过Ti3+自掺杂可以很好提高Ti O2可见光催化活性,但是目前制备Ti3+掺杂Ti O2的方法较复杂,形成的Ti3+掺杂易在表面积聚而被进一步氧化,影响其光催化稳定性,不利于实际应用.因此,开发具有良好电子-空穴分离效率的可见光催化剂引起了广泛的研究兴趣.本文通过原位自掺杂Ti3+来提高Ti O2可见光光催化活性.以Ti Cl3为钛源,H2O为溶剂,F127为软模板,采用溶剂挥发诱导自组装的方法制备了蠕虫状Ti3+自掺杂的介孔Ti O2.采用X射线衍射(XRD)、N2物理吸附、紫外-可见漫反射(UV-vis)、透射电子显微镜和电子顺磁共振(EPR)对所制备样品结构、结晶度和形貌等进行了表征分析.通过控制表面活性剂用量和焙烧温度优化了Ti3+自掺杂介孔Ti O2的光催化活性.结果表明,在模拟太阳光照射下,所制样品对气相光催化氧化NO和水相降解有机染料亚甲基蓝表现出优异的催化性能和稳定性.Ti3+自掺杂介孔Ti O2有效扩展了催化剂的光吸收范围,提高了光生电子空穴的迁移效率.其优异的光催化活性和稳定性主要归因于掺杂在Ti O+2骨架中的Ti3和所合成催化剂多孔性之间的协同效果.固体UV-vis结果表明,所合成的Ti O+2具有很好的可见光响应,主要归因于在Ti O2材料合成过程中,部分Ti3+未被完全氧化,Ti3掺入可以有效降低Ti O2的禁带宽度.通过计算可知合成的Ti O2禁带宽度为2.7 e V.通过低温EPR测试进一步证明了Ti3+的存在,而且Ti3+主要掺杂在Ti O2体相中.N2物理吸附结果表明,随焙烧温度不断提高,所得产物的比表面积先增加后减少,当焙烧温度在500 oC时,比表面积最大,但至550 oC时,比表面积、孔径和孔体积增大,表明催化剂的孔结构被破坏.表面活性剂F127的用量对样品比表面积和孔径大小也有影响,当其用量为0.54 g时,所得产物的比表面积最大.我们将所合成的Ti O2应用于污染气体NO的氧化,考察了焙烧温度和表面活性剂用量对光催化剂性能的影响.结果表明,当表面活性剂用量为0.54 g,焙烧温度为500 oC时,所制催化剂在模拟太阳光和可见光照射下都表现出最好的NO去除转化率.将使用过的催化剂离心洗涤后进行连续反应3.5 h,依然保持很高的NO去除转化率.催化剂高活性及稳定性的主要原因是Ti3+的掺杂将Ti O2光响应范围拓展到可见光区域,且Ti3+掺杂和介孔结构之间的协同作用有利于促进光生电子和空穴的分离.当催化剂在低于500 oC焙烧时,所得催化剂结晶度较低,不利于光生电子-空穴的分离,而高温焙烧则会导致催化剂介孔结构遭到破坏,不利于NO气体吸附和产物脱附.表面活性剂对催化剂活性影响较小,在可见光照射下催化剂均表现出很好的光催化活性.此外,该Ti3+自掺杂介孔Ti O2在液相条件下对有机染料亚甲基蓝也表现出很好的去除效果,可见光照射2 h,亚甲基蓝去除率接近100%.     

水热合成Fe3+掺杂ZnO复合材料及其光催化活性

以Zn(Ac)2·2H2O、Fe(NO3)3·9H2O和NaOH为原料,采用水热法合成了Fe3+掺杂ZnO复合材料. 并用X射线衍射和扫描电子显微镜测试技术对合成样品的结构和形貌进行了表征. 结果表明,Fe3+掺杂ZnO合成产物为直棒状,直径为500 nm,长度为3 μm左右. 样品的紫外可见漫反射分析结果表明,在300～500 nm紫外可见光区域均有强的吸收. Fe3+掺杂ZnO作为光催化剂降解有机染料性能优于纯ZnO材料.     

碳修饰钨酸铋光催化降解水体中的邻苯二甲酸酯

以Bi(NO3)3.5H2O、Na2WO4.2H2O为反应物,采用水热法,经由葡萄糖炭化合成了碳修饰Bi2WO6(C-Bi2WO6)催化剂;考察了C-Bi2WO6光催化降解3种邻苯二甲酸酯(PAEs)的催化性能.结果表明:C-Bi2WO6对PAEs的降解效果优于Bi2WO6,特别是在葡萄糖与Na2WO4.2H2O质量比约10∶100条件下得到的催化剂的催化性能最优.与此同时,当PAEs的pH=6时,降解效果最好;而PAEs的浓度也对PAEs的光催化降解有一定的影响.     

H_3PW_(12)O_(40)掺杂TiO_2介孔材料的制备及光催化性能

以P123为模板剂,采用溶胶-凝胶的溶剂热合成方法制备了H3PW12O40掺杂TiO2介孔材料H3PW12O40/TiO2.利用紫外可见漫反射吸收光谱(UV-vis/DRS)、X射线粉末衍射(XRD)、N2吸附和透射电子显微镜(TEM)手段对所制备的材料进行结构表征,罗丹明B(RB)为模型污染物评价其光催化性能.结果表明,所制备的介孔材料具有锐钛矿与板钛矿复合的晶型结构、大的BET比表面积和孔径均匀分布的介孔结构.光催化实验表明,H3PW12O40/TiO2可将罗丹明B完全矿化.     

太阳光活性的铁酸铝-二氧化钛纳米复合光催化剂

以共沉淀法制备的铁酸铝和溶胶-凝胶法制备的二氧化钛粉体作为前驱体, 合成了铁酸铝-二氧化钛纳米复合材料, 通过曙红染料和甲基橙的光催化降解来评价该纳米复合材料的光催化活性, 并与单一二氧化钛的光催化性能进行了比较. 实验结果表明: 无论是紫外光还是太阳光的激发下, 铁酸铝-二氧化钛纳米复合材料的光催化活性均优于同样条件下所制备的单一二氧化钛纳米材料, 理想的铁酸铝掺杂浓度分别是1.0%(紫外光)和9.0%(太阳光). 由于在二氧化钛基体中掺入铁酸铝纳米粒子, 既可以促进光生载流子的电荷分离, 又可以使二氧化钛的光响应波长向可见光区域拓展, 提高了太阳能利用率, 从而使其在太阳光下具有更优越的光催化活性.     

钛硅分子筛TS-1合成晶化气氛的影响

考察了不同晶化气氛(N2、H2、A ir、O2)对合成钛硅分子筛TS-1的影响,用XRD、IR和N2吸附/脱附对所合成的钛硅分子筛进行结构表征,发现在H2气氛下合成的TS-1结晶度最高,锐钛矿的含量最少;O2气氛下合成的TS-1中锐钛矿含量最高.以氯丙烯氧化为模型反应,考察了不同晶化气氛下合成的钛硅分子筛的催化活性和双氧水的利用效率.结果表明,在H2气氛下所合成的钛硅分子筛的双氧水的利用效率最高.     

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%.     

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.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

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.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.