共查询到19条相似文献,搜索用时 93 毫秒
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以2-(2-吡啶基)咪唑(pIM)、Co2+和NaVO3为原料,在水热条件下,制备了新的钒氧簇化合物[Co (pIM) V2O6](1)。采用X射线单晶衍射、粉末X射线衍射、傅里叶变换红外光谱和元素分析等方法对化合物进行了表征。单晶解析表明,该化合物由VO4四面体和CoO3N2四方锥通过氧原子共边、共角连接成二维结构。基于钒氧簇在催化氧化体系中的高效活性,1作为非均相反应的催化剂,在以H2O2为氧化剂的催化烯烃环氧化反应中表现出优秀的催化性能,催化剂能够多次重复使用且活性基本保持不变。此外,磁化率研究表明1中存在反铁磁相互作用。 相似文献
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综述了以过氧化氢为氧源,多金属氧酸盐催化烯烃环氧化的研究进展,尤其是针对基于多金属氧酸盐的反应控制相转移催化体系近年来的研究进展进行了详细阐述. 相似文献
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催化分子氧环氧化烯烃的研究进展 总被引:3,自引:0,他引:3
环氧化合物是一类十分有用的合成中间体 ,广泛应用于石油化工、精细化工和有机合成 .但至今为止 ,工业上除用分子氧直接氧化乙烯制环氧乙烷外 ,其它所有 C2 以上的环氧化合物还不能用分子氧直接氧化相应的烯烃制得 .国外生产环氧丙烷和环氧氯丙烷的主要方法有卤醇法、Halcon法 ,而国内则以卤醇法为主 .另外 ,过酸法常用于精细产品的合成中 ,以 H2 O2 、Na Cl O等为氧源的环氧化研究 ,近年来也已取得了较大的进展 .卤醇法较早应用于生产 ,但存在严重的设备腐蚀和环境污染问题 ;Halcon法利用 ROOH为氧源 ,有联产品 ,生产过程较复杂 ,基本… 相似文献
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过氧化氢为氧源催化烯烃环氧化研究 总被引:2,自引:0,他引:2
环境友好催化烯烃环氧化是催化氧化领域中的一大热点,过氧化氢作为一种理想的清洁氧源日益受到人们的重视。本文从匀相和多相催化两方面综述了近年来以过氧化氢为氧源催化烯烃环氧化研究的主要进展,对一些有很好工业化应用前景的反应体系作了详细介绍。 相似文献
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键联聚乙二醇高分子担载锰(Ⅲ)卟啉的合成及催化烯烃环氧化反应性… 总被引:2,自引:1,他引:2
本文研究了键联聚乙二醇高分子担载锰(Ⅲ)卟啉的合成,以及在CH2Cl2/H2O两相体系中催化苯乙烯环氧化反应的性能,探索了催化反应体系中溶液pH值、NaOCl浓度、轴向配体及相转移催化剂对催化反应的影响。结果说明键联聚乙二醇高分子担载锰(Ⅲ)卟啉是烯烃环氧化反应的一种有效催化剂,其中聚乙二醇链可以络合Na,使OCl富集于金属卟啉周围,起到较好的相转移催化作用。在催化反应的各影响因素中,水相pH值对 相似文献
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Phase-transfer catalytic epoxidation of olefins under liquid-liquid biphasic conditions 总被引:1,自引:0,他引:1
The phase transfer catalytic epoxidation of various olefins in the presence of cocatalysts (sodium tungstate and phosphoric
acid) and an oxidant (hydrogen peroxide) in an organic/aqueous two-phase medium was investigated. The different conversions
and selectivities casued by olefins of different carbon-carbon double bonds are discussed.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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Saili Wei Yuhai Tang Xiaoqian Xu Guojin Xu Yong Yu Yang Sun Yuansuo Zheng 《应用有机金属化学》2011,25(2):146-153
This communication describes the design and application of a novel catalytic epoxidation system derived from the initial immobilization of a homogeneous sulfonato (salen)Mn(III) complex on two solid carriers (silica gel and siliceous earth) and subsequent dispersion of the supported manganese complexes into ionic liquid 1‐butyl‐3‐methylimidazolium hexafluorophosphate (BMImPF6) and 1‐butyl‐3‐methylimidazolium tetrafluoroborate (BMImBF4) for recycling. The performance of chiral (salen)Mn(III) system in enantioselective epoxidation of olefins was investigated systematically. Even higher enantioselectivity than that of the homogeneous counterpart was obtained with similar catalytic activity. In particular, the best catalytic result is that the combination of the silica gel‐supported (salen)Mn(III) catalyst and BMImPF6 affords 97–100% ee for epoxidation of α‐methylstyrene, and high ee values were retained even after three cycles. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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The epoxidation of α,β-unsaturated carbonyl compounds such as enones and enals was efficiently achieved with tetrabutylammonium peroxydisulfate in the presence of equimolar amounts of hydrogen peroxide and NaOH in acetonitrile or methanol at 25 °C in excellent yields. Base-sensitive substrate such as cinnamaldehyde could be successfully epoxidized in short reaction time under mild reaction conditions. 相似文献
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Four new kinds of heterogeneous catalysts for olefins epoxidation were obtained by grafting diamines on organic polymer–inorganic hybrid material, zirconium poly (styrene‐phenylvinylphosphonate)‐phosphate (ZPS‐PVPA), and subsequently coordinating with Schiff base Mo(VI) complexes. The catalysts were characterized by IR, XPS, SEM and TEM. All catalysts were evaluated through the epoxidation of olefins using tert‐BuOOH as oxidant. The heterogeneous catalysts possess the advantages of high conversion, selectivity and excellent reusability. The catalysts were easily separated from the reaction systems and could be reused 13 times without significant loss of catalytic activity. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Versatile synthetic intermediates—α,β‐epoxyketones and α,β‐epoxyaldehydes—can be obtained through asymmetric organocatalytic epoxidation of α,β‐unsaturated ketones and aldehydes. This Review focuses on some recent advances in these epoxidation reactions with respect to scope and limitations with polyamino acids, phase‐transfer catalysts (PTCs), amines, and guanidines as chiral organocatalysts. Furthermore, recent results obtained with chiral peroxides are discussed. © 2010 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Published online in Wiley InterScience ( www.interscience.wiley.com ) DOI 10.1002/tcr.201000006 相似文献
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Schiff base‐functionalized boehmite nanoparticle‐supported molybdenum and vanadium complexes: efficient catalysts for the epoxidation of alkenes 下载免费PDF全文
Boehmite nanoparticles, with high surface area and high degree of surface hydroxyl groups, were prepared via hydrothermal‐assisted sol–gel processing of aluminium 2‐butoxide. The produced powder was covalently functionalized with 3‐(trimethoxysilyl)propylamine, and then, in order to support vanadium oxosulfate and molybdenum hexacarbonyl complexes, all the terminal amine groups were changed to Schiff bases by refluxing with salicylaldehyde. These catalysts were applied in the epoxidation of cis‐cyclooctene and other olefins with tert‐BuOOH in CCl4. The catalytic procedures for both catalysts were optimized for various parameters such as solvent and oxidant. Recycling experiments revealed that these heterogeneous nano‐catalysts could be repeatedly applied for the epoxidation of alkenes. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献