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无水SnCl_4及SbCl_5是典型的Lewis酸,是有机反应中常用的催化剂。它们的溶剂化热效应早已受到人们的关注,然而用NMR方法来研究它们的溶剂化作用至今未见报道。本工作用~(119)Sn、~(121)Sb及(13)C NMR考察了典型Lewis酸无水SnCl_4、SnCl_5与二十几种Lewis碱的相互作用,直接证实了Lewis酸碱反应为电子的授受过程。 相似文献
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高分子催化剂是功能性高分子的重要组成部分,是目前催化剂研究的方向之一,近年来发展很快。我们曾将在空气中强烈水解的Lewis酸四氯化钛与聚苯乙烯反应制备了一种比较稳定的复合物,它对酯化、缩醛、缩酮等有机反应具有良好的催化效能,也可作为α-甲基苯乙烯正离子聚合的有效催化剂,在室温下即可获得高分子量的聚合物。为了进一步改进其稳定性和重复使用性能,本文合成了一种苯乙烯与丙烯脂的共聚交联小球,然后与四氯化钦反应制成了一种更加稳定的高分子载体Lewis酸催化剂,它不但对醋化、缩醛、缩酮等有机反应有很高的催化活性,而且重复使用性能大为改善,是一种很有希望应用于实际的高分子催化剂。 相似文献
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有机小分子催化聚合反应是合成化学领域新的研究方向。有机催化环醚(主要为环氧化物)与环状酸酐共聚制备聚酯的合成路线,由于单体具有来源广泛、有机催化剂低毒、对水和空气不敏感等特点,因而应用前景广阔。本文按有机小分子催化剂、环醚与环状酸酐的种类综述了近年来出现的有机催化共聚合成聚酯的反应,并详细讨论了该共聚反应及其机理,尤其是高催化活性和聚合可控性的Lewis酸碱对催化共聚的机理;提出了利用Lewis酸为增长链阴离子提供结构因素(如基团和电子结构效应)来调控聚合的方法。今后,催化环氧化物与环状酸酐共聚研究的中心任务仍然是发展新的高活性有机催化剂,并实现"活性"的全交替共聚反应,进一步提高共聚物的分子量,并实现共聚反应的化学选择性、区域和立体选择性的精确控制。 相似文献
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采用溶胶-凝胶法和浸渍法制备了V2O5/SiO2催化剂,并用XRD,IR,TPD和活性评价等手段对催化剂的表面构造、化学吸附性能和异丁烷选择氧化反应性能进行了研究.结果表明:催化剂表面由Lewis碱位V=O双键的端氧和Lewis酸位V5+构成,异丁烷分子主要通过甲基中的H双位吸附在催化剂表面的Lewis碱位上,异丁烯分子可通过甲基的H吸附在催化剂表面的Lewis碱位,也可通过C=C双键吸附在催化剂表面的Lewis酸位上.在常压条件下,异丁烷选择氧化产物主要有异丁烯、甲基丙烯醛和甲基丙烯酸,其中深度氧化产物CO2主要由通过C=C吸附的异丁烯继续反应生成. 相似文献
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乙酸苄酯在H-β沸石上的催化合成 总被引:7,自引:0,他引:7
β沸石是一种高硅大孔沸石^[1],H-β沸石已用于催化某些有机反应,例如芳醚的酰化^[2],歧化反应^[3]等。酯化反应通常用浓硫酸或Lewis酸作催化剂,但传统的方法有催化剂易流失,反应产物难纯制,腐蚀性和有毒废物等缺点,用HZSM-5等固体酸催化剂^[4,5]能显克服这些,本报道用H-β沸石作催化剂合成乙酸苄酯的结果。 相似文献
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CuO-CaO/SiO2超细催化剂结构及糠醛加氢反应性能的研究 总被引:3,自引:0,他引:3
采用溶胶-凝胶法制备出超细CuO—CaO/SiO2催化剂,用XRD、BET、TEM、XPS、TPR对催化剂结构进行了表征.将催化剂用于糠醛催化加氢反应,制备2-甲基呋喃,研究了活性组分负载量对催化剂结构及性能的影响。结果表明,载体对活性组分的分散能力随着负载量的减少而增大;催化剂的比表面积和孔体积随负载量的增加而减小,而孔径逐渐增大;活性组分与载体之间存在较强的相互作用.催化剂在糠醛加氢反应中表现出很高的活性;选取适宜的活性组分负载量,可高选择性制取2-甲基呋喃. 相似文献
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Tomoya Higashihara Mao‐Chun Fu Takaaki Uno Mitsuru Ueda 《Journal of polymer science. Part A, Polymer chemistry》2016,54(8):1153-1158
Random copolycyanurates with a low number of amide units in the main chain have been developed as a candidate of dismantlable adhesives based on the rapid decrease of the molecular weights during the rearrangement to polyisocyanurates by a thermal treatment. The random copolycyanurates were prepared by the phase‐transfer‐catalyzed polycondensation of 2,4‐dichloro‐6‐methoxy‐1,3,5‐triazine with bisphenol A and a new bisphenol containing an amide unit in the presence of tetrabutylammonium bromide. They exhibited an excellent adhesive property for the silicon and copper deposited on the silicon substrate after the high thermal treatment of 240 °C under 0.6 MPa compression, and the die shear strengths of these polymers dramatically decreased at 260 °C for 1 h. Random copolycyanurates containing the amide unit are shown to be promising materials for dismantlable adhesion. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1153–1158 相似文献
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Xiao Fan Zhongping LiDandan Yao Yuwei ZhangHe Li Xiaoming LiuYing Mu 《Comptes Rendus Chimie》2014,17(11):1102-1108
Two stable blue-light-emitting molecular materials containing twisted binaphthyl and peripheral triphenylamine groups were synthesized by Suzuki and Heck cross-coupling reactions. Both compounds exhibit excellent thermal and morphologic stabilities, high glass transition temperatures and good fluorescence quantum yield in films. They serve as both hole-transporting and blue emission materials in organic light-emitting diodes with good external quantum efficiencies. 相似文献
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Nanometer-sized conjugated 1,4- and 1,3,5-ethynylphenyl oligomers were synthesized starting from 3,5-di(trimethylsilylethynyl)phenylacetylene and p-[3,5-di(trimethylsilylethynyl)-1-ethynylphenyl]phenyl acetylene by cross-coupling reaction with a convenient haloaryl derivative, catalyzed by palladium(II)/copper(I), in excellent yield. The terminal acetylenes were efficiently prepared by a specific protection-deprotection methodology. All ethynylphenyl homologues obtained show fluorescence emission, with the bathochromic shift of approximately 20 nm by each ethynylphenyl unit increasing the conjugate chain. Parallel conjugated ethynylphenyl chains were prepared through the insertion of a 1,5-naphthalene subunit, and the compounds exhibit fluorescence radiation emission. 相似文献
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Liu H Zhao Q Li Y Liu Y Lu F Zhuang J Wang S Jiang L Zhu D Yu D Chi L 《Journal of the American Chemical Society》2005,127(4):1120-1121
In this contribution, large-area organic charge-transfer complex (AgTCNQ and CuTCNQ) nanowires were synthesized by organic vapor-solid-phase reaction at mild experimental conditions. These nanowires were facilitated on the surface of Cu and Ag foils or different kinds of substrates coated with a layer of silver and copper on a large scale. The excellent field emission properties were observed in the as-grown AgTCNQ and CuTCNQ nanowires. They should have great potential in vacuum device applications. 相似文献
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一种连有C_60功能基团的聚磷腈的合成 总被引:3,自引:0,他引:3
采用一种后功能化的方法合成一种连有C_60侧基的聚磷腈高分子,即首先合成 了连有苄溴基团的聚磷腈,然后将苄溴基团转换为叠氮基团,再合成连有C_60侧基 的聚磷腈高分子,通过核磁、红外、紫外可见光谱、分子量测定等手段对所得高分 子进行了鉴定,此合成方法为聚磷腈功能材料的合成提供了一条新途径。 相似文献
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Wang X Guan H Chen S Li H Zhai T Tang D Bando Y Golberg D 《Chemical communications (Cambridge, England)》2011,47(45):12280-12282
Self-stacked Co(3)O(4) nanosheets separated by carbon layers were synthesized via a facile method. They exhibit excellent electrochemical performance that results from superior electronic conductivity endowed by carbon, a reduced Li(+) diffusion length within the building blocks and a large electrode/electrolyte contact area due to the interspaces between the blocks. 相似文献
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Blue light-emitting and hole-transporting amorphous molecular materials based on diarylaminobiphenyl-functionalized bimesitylenes 总被引:1,自引:0,他引:1
Moorthy JN Venkatakrishnan P Huang DF Chow TJ 《Chemical communications (Cambridge, England)》2008,(18):2146-2148
The diarylaminobiphenyl-functionalized bimesityls and exhibit amorphous nature, high thermal stability and excellent blue emission in the solid state. They serve as both hole-transporting and emissive materials in OLEDs for blue emission with high external quantum efficiencies. 相似文献
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Trinitromethyl-substituted 5-nitro- or 3-azo-1,2,4-triazoles: synthesis, characterization, and energetic properties 总被引:5,自引:0,他引:5
Various new polynitro-1,2,4-triazoles containing a trinitromethyl group were synthesized by straightforward routes. These high nitrogen and oxygen-rich compounds were fully characterized using IR and multinuclear NMR spectroscopy, elemental analysis, natural bonding orbital (NBO) analysis, and differential scanning calorimetry (DSC) and, in the case of 12, with single crystal X-ray structuring. The heats of formation for all compounds were calculated with Gaussian 03 (revision D.01) and then combined with experimentally determined densities to determine detonation pressures (P) and velocities (D) of the energetic materials (Cheetah 5.0). They exhibit high density, good thermal stability, acceptable oxygen balance, positive heat of formation, and excellent detonation properties, which, in some cases, are superior to those of TNT, RDX, and HMX. 相似文献