共查询到19条相似文献,搜索用时 62 毫秒
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羊毛—过渡金属络合物的合成及其选择性催化氢化性能的研究 总被引:1,自引:2,他引:1
合成和初步表征了以天然高分子羊毛为载体的羊毛一钯单金属和羊毛-钯-铁双金属络合物催化剂;研究表明,在羊毛-钯络合物催化剂中,引入第二金属能极大地改进它的催化性能,提高其催化选择性,更有效的接近酶催化剂的特征.在常温常压下,以羊毛-钯-铁双金属络合物作催化剂,能顺利地使氯代硝基苯和氯代苯甲醛选择氢化成氯代苯胶和氯代苯甲醇.产率均为100%,有效地抑制了氰取代基的氢解脱除,络合物催化剂中的钯/铁原子比极大地影响着该类氢化反应选择性,在氯代硝基苯和氯代苯甲醛的氢化反应中,最佳的钯/铁原子比分别为1:3和15:1,这时反应的选择性均达到100%,溶剂和温度对氢化反应速度均有一定的影响. 相似文献
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自从Tomalia和Newkome报道树枝形聚合物以来[1],树状分子的研究主要集中在它的合成与表征上.二十世纪80年代中期,出现了具有非常规整、精致和球形结构的树状大分子,其分子体积、形状和功能可在分子水平精确设计和控制.这些特征的结合应用在催化领域,将使树状大分子有可能消除均相催化与非均相催化之间的差别,发展出一类具有优异性能的催化剂.1994年Van Koten等[2]报道了首例树状分子金属配合物催化剂,它在催化研究领域的应用引起了人们极大的关注,并已取得很大的进展[3].与可溶性高分子负载催化剂相比,树状分子催化剂具有如下优点:1)可精… 相似文献
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无机和金属有机多核分子树络合物 总被引:2,自引:0,他引:2
本文介绍近年来国外无机和金属有机多核分子树络合物的研究进展, 主要侧重于这类分子树络合物的设计合成、物化特性、催化反应及其应用前景。 相似文献
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将自然界资源丰富但化学性质上极其惰性的氮气分子在温和条件下转化为氨及其他含氮化合物,具有非常重要的意义。过渡金属络合物引发氮分子的活化及官能化已成为现代工业固氮的一大研究热点。本文回顾了氮分子与双核过渡金属络合物结合的键型模式,总结了影响氮分子活化的诸多因素如配体调变效应、金属调变效应等,对双核过渡金属络合物引发的双氮裂解、双氮官能化及CO/CO2协助双氮活化官能化等反应的实验与理论研究现状和进展进行了简要综述,并对未来过渡金属络合物在氮分子固定的应用发展作了展望。 相似文献
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用光谱滴定法研究了手性Salen金属配合物(SalenFe~(III), SalenCo~(II))与 四种咪唑类客体在CH_2Cl_2中的分子识别行为,发现手性Salen金属配合物与咪唑 ,N-甲基咪唑,2-甲基咪唑的配位数为2,与克霉唑的配位数为1。各识别体系缔 合常数的顺序对SalenFe~(III)为: K(Im) > K(2-MeIm) > K(N-MeIm) > K(GMZ), 对SalenCo~(II)为:K(Im) > K(2-MeIm) > K(N-MeIm)。测定的识别反应的△ _rG_m~0, △_rH_m~0, △_rS_m~0表明此类识别反应为放热、熵减少的过程,反应 体系存在焓-熵补偿关系。采用分子力学和量子化学方法进行的理论研究对实验结 果作出了合理的解释。 相似文献
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金属配位模板聚合物的分子识别特性的研究 总被引:5,自引:0,他引:5
以Co(Ⅱ)和敌鼠配合物为模板,4-乙烯吡啶为功能基单体,乙二醇二甲基丙烯酸酯为交联剂,采用分子印迹技术,合成了具有类似于金属螯合抗体结合位点的金属配位模板聚合物。系统研究了金属离子对模板聚合物靠拢性结构敌鼠的调节作用。 相似文献
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Edward A. Karakhanov Lyusyen M. Karapetyan Yulia S. Kardasheva Anton L. Maksimov Elena A. Runova Vitaliy A. Skorkin Maria V. Terenina 《Macromolecular Symposia》2006,235(1):39-51
Summary: The results of studying a number of reactions catalyzed by several types of soluble macromolecular catalytic systems capable of selectively binding organic substrates, namely, modified cyclodextrins, calixarenes and dendrimers are presented. The use of modified cyclodextrins as components of a catalytic system in the phenol and benzene hydroxylation by hydrogen peroxide allows one both to increase the catalytic activity and to change significantly the chemical selectivity. Phosphorilated calixarene – Rh catalytic systems was found to be catalytically active in hydroformylation of linear alkenes C7–C12. The results of experiments on the oxidation of C7–C16 alkenes show that, when the ligand is the dendrimer molecule, the fraction of forming methyl ketones substantially increases for the substrates C7–C9. For the higher alkenes, this effect is not observed. 相似文献
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Carbonylation of olefins, alcohols and halides using homogeneous as well as heterogeneous catalysts has been discussed. Highlights
of contributions on the activity, selectivity and stability of catalysts for carbonylation reactions are discussed. Kinetics
and mechanism including characterization of the intermediate catalytic species has also been reviewed. The performance of
anchored Pd complexes on mesoporous supports (MCM-41 and MCM-48), water soluble Pd complexes and supported Pd catalysts in
carbonylation of aryl alcohols and olefins has been discussed in the context of catalyst-product separation. Some aspects
of kinetic modelling and reaction engineering of these multiphase catalytic reactions have also been reviewed. 相似文献
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Tyler J. Finnegan Vageesha W. Liyana Gunawardana Prof. Jovica D. Badjić 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(53):13280-13305
Nerve agents are tetrahedral organophosphorus compounds (OPs) that were developed in the last century to irreversibly inhibit acetylcholinesterase (AChE) and therefore impede neurological signaling in living organisms. Exposure to OPs leads to a rapid development of symptoms from excessive salivation, nasal congestion and chest pain to convulsion and asphyxiation which if left untreated may lead to death. These potent toxins are prepared on a large scale from inexpensive staring materials, making it feasible for terrorist groups or states to use them against military and civilians. The existing antidotes provide limited protection and are difficult to apply to a large number of affected individuals. While new prophylactics are currently being developed, there is still need for therapeutics capable of both preventing and reversing the effects of OP poisoning. In this review, we describe how the science of molecular recognition can expand the pallet of tools for rapid and safe sequestration of nerve agents. 相似文献
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新型后过滤金属烯烃聚合催化剂——镍系烯烃聚合催化剂 总被引:1,自引:1,他引:1
镍系烯烃聚合催化剂是近年来受到广泛关注的一类新型催化剂,是配位催化研究的热点之一。这类催化剂具有高催化活性、单活性中心和良好的分子剪栽性,可以在分子层次上实现烯烃聚合的分子设计与组装。本文介绍了镍系烯烃聚合催化剂的发展和研究概况,并评述了聚合特性及最新研究进展。 相似文献
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新型后过渡金属烯烃聚合催化剂--镍系烯烃聚合催化剂* 总被引:1,自引:0,他引:1
镍系烯烃聚合催化剂是近年来受到广泛关注的一类新型催化剂,是配位催化研究的热点之一。这类催化剂具有高催化活性、单活性中心和良好的分子剪栽性,可以在分子层次上实现烯烃聚合的分子设计与组装。本文介绍了镍系烯烃聚合催化剂的发展和研究概况,并评述了聚合特性及最新研究进展。 相似文献
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Summary: Siliceous mesoporous molecular sieves MCM-41, MCM-48 and SBA-15 and organised mesoporous alumina represent progressive supports for new heterogeneous catalysts for olefin metathesis and metathesis polymerization. In combination with Mo and Re oxides they provide catalysts of considerably higher activity in comparison with those based on conventional silica and alumina. Immobilization of Mo and Ru alkylidenes on these materials led to the highly active and selective catalysts with negligible leaching of transition metal. 相似文献