高分子固载化烯烃歧化催化剂研究进展

本文了国内外对高分子负载烃歧化催化剂的研究概况。高分子固载化金属催化剂的研究始于六十年代末。由于高分子负载金属催化剂兼具均相和多相催化剂的优点，既具有均相催化剂的高活性又具多相催化剂的易回收分离，因而受到越多的高分子和催化工作者的重视。这种技术在加氢，氧化，脱氢，脱氢，环氧化，氢甲酰化，硅氢加成，不对称合成等有机催化领域都已得到不同程度的研究和应用，并获得了良好的效果，仅近年来就有许多综述和专著对     

新型固载化的匀相催化剂

多相催化和匀相催化是催化领域里的两大类型,两者相比,匀相催化剂具有高活性、高选择性、反应条件温和等优点.然而,催化剂和产品分离难的问题,使匀相催化剂的应用受到很大的限制.20世纪60年代末,人们就开始将过渡金属配合物以化学键合形式锚定在载体上,制备负载型催化剂.这种固载化催化剂介于匀相催化剂与多相催化剂之间,它既具有匀相催化的特性,又具有多相催化产品与催化剂易分离的优点.而且,对这类催化剂进行研究,有可能在分子水平上研制出反应性能优异的催化剂,并对其催化作用机理有更进一步的认识.固载化匀相催化剂是一种很有前途的…     

对映选择催化环丙烷化反应中活性铜催化剂组成的测定

对映选择催化环丙烷化反应中活性铜催化剂组成的测定臧二乐，李萍，胡秉方（北京农业大学应用化学系，北京１０００９４）关键词铜络合物，催化机理，环丙烷化手性铜（Ⅱ）络合物已广泛应用于催化环丙烷化反应［１，２］．关于反应中催化活性体的组成，结构及诱导机理却不...     

Click化学固载催化剂催化多相有机反应研究进展

催化剂固载实现均相催化多相化已成为当今有机化学领域的一大研究热点,而Click化学作为一种极其有效的均相催化剂的固载手段得到了广泛的应用.主要从硅胶、聚乙二醇(PEG)、聚苯乙烯(PS)、全氟烷烃、树枝状大分子等固载基质方面,综述了近几年来运用Click化学实现的各类催化剂的固载,并通过一系列反应对固载后的催化剂进行了活性和稳定性评价.     

离子液体固载化及应用研究

离子液体固载化是将离子液体通过物理吸附或化学键合的方法负载到不同的载体上,得到一种新型固体材料,兼具了离子液体与载体的特征,能够显著提升离子液体的利用率,解决离子液体黏度大、传质及分离困难等问题,拓展了离子液体的应用领域。本文根据不同的载体类型,综述了近年来离子液体固载化的研究进展及应用情况,总结了不同载体的优缺点及现阶段研究和应用发展中存在的一些问题,并对固载化离子液体的应用前景进行了展望。     

一种新型手性席夫碱的合成及其在不对称环丙烷化反应中的催化性能

在不对称催化的发展过程中,设计与合成新的手性配体一直是人们所关注的热点,并已取得很大的进展[1].     

手性金属配合物催化的不对称环丙烷化反应的新进展

总结了近年来关于环丙烷化反应中各种手性金属催化剂的研究进展, 包括席夫碱、噁唑啉、卟啉、联吡啶及四吡啶、羧酸酯等类型的手性化合物作为配体的金属催化剂.     

铜化合物催化重氮乙酸乙酯环丙烷化反应

研究了以铜化合物催化重氮乙酸乙酯与烯烃的环丙烷化反应,首次计算了反应关键中间体铜-卡宾的环丙烷化选择性P及该中间体的解离常数K,结果表明:1.反应体系中可能存在着铜-卡宾与游离卡宾的平衡;2.P、K与所用的催化剂有关。使用不同的催化剂,温度对反应选择性的影响也不同,对以上结果进行了理论探讨。     

不对称环丙烷化反应

利用手性类卡宾分子对烯烃的加成,可合成非对称取代的环丙烷环。其不对称诱导一般受立体和电子因素控制。本文主要综述 Simmons-Smith 反应,重氮化合物,异丙叉三苯基膦,以及一些金属有机化合物的催化热解反应在不对称环丙烷环合成中的应用,并以潜在杀虫剂环丙烷甲酸化合物的合成为例进行了讨论。     

环丙烷／Cope重反应的研究进展

综述了环丙烷化／Ｃｏｐｅ重排反应合成七元环结构有机化合物的方法及研究进展。参考文献３８篇。     

Immobilization of Pd(II) Catalysts for Cyclopropanation in Ionic Liquid

Ｈｏｍｏｇｅｎｅｏｕｓｃａｔａｌｙｓｉｓｏｆｆｅｒｓｍａｎｙａｄｖａｎｔａｇｅｓｏｖｅｒｈｅｔｅｒｏｇｅｎｏｕｓｃａｔａｌｙｓｉｓｗｉｔｈｒｅｓｐｅｃｔｔｏａｃｔｉｖｉｔｙ ,ｓｅｌｅｃｔｉｖｉ ｔｙ ,ｆｌｅｘｉｂｉｌｉｔｙｏｆｏｐｅｒａｔｉｏｎ .Ｈｏｗｅｖｅｒ ,ｔｈｅｃｏｎｔｉｎｕｏｕｓｃａｔ ａｌｙｓｔｃｏｎｓｕｍｐｔｉｏｎ ,ｃａｔａｌｙｓｔｒｅｍｏｖａｌｆｒｏｍｔｈｅｐｒｏｄｕｃｔｓａｎｄｃａｔａｌｙｓｔｄｉｓｐｏｓａｌｈａｖｅｓｔｉｌｌｔｏｂｅｉｍｐｒｏｖｅｄ .Ａｎａｔ ｔｒａｃｔｉｖｅａｐ…     

Immobilization of Pd（Ⅱ）Catalysts for Cyclopropanation in Ionic Liquid

Cyclopropanation of styrene with ethyl diazoacetate catalyzed by Pd(Ⅱ） in ionic liquid [omim][BF4] was investigated.Palladium catalysts can be effectively immobilized in ionic liquid.The catalysts PdCl2 and cyclopalladated complex 2 contained in ionic liquid could be recycled for 6 and 7 times,respectively,without losing the efficiency.     

Bringing Homogeneous Iron Catalysts on the Heterogeneous Side: Solutions for Immobilization

Noble metal catalysts currently dominate the landscape of chemical synthesis, but cheaper and less toxic derivatives are recently emerging as more sustainable solutions. Iron is among the possible alternative metals due to its biocompatibility and exceptional versatility. Nowadays, iron catalysts work essentially in homogeneous conditions, while heterogeneous catalysts would be better performing and more desirable systems for a broad industrial application. In this review, approaches for heterogenization of iron catalysts reported in the literature within the last two decades are summarized, and utility and critical points are discussed. The immobilization on silica of bis(arylimine)pyridyl iron complexes, good catalysts in the polymerization of olefins, is the first useful heterogeneous strategy described. Microporous molecular sieves also proved to be good iron catalyst carriers, able to provide confined geometries where olefin polymerization can occur. Same immobilizing supports (e.g., MCM-41 and MCM-48) are suitable for anchoring iron-based catalysts for styrene, cyclohexene and cyclohexane oxidation. Another excellent example is the anchoring to a Merrifield resin of an Fe^II-anthranilic acid complex, active in the catalytic reaction of urea with alcohols and amines for the synthesis of carbamates and N-substituted ureas, respectively. A SILP (Supported Ionic Liquid Phase) catalytic system has been successfully employed for the heterogenization of a chemoselective iron catalyst active in aldehyde hydrogenation. Finally, Fe^III ions supported on polyvinylpyridine grafted chitosan made a useful heterogeneous catalytic system for C–H bond activation.     

茂金属催化剂的负载化

茂金属催化剂是继齐格勒-纳塔催化剂之后的新一代烯烃聚合催化剂,与多活性中心催化剂相比,这种单一活性中心类型的催化剂具有聚合活性较高、聚合物分子量分布较窄等特点。其中,负载化是茂金属催化剂实用化的重要课题,它克服了均相催化体系中聚合物形貌不可控的缺点,降低了助催化剂的用量。近些年来茂金属负载化的研究仍很活跃。本文总结了近十年来茂金属负载化的研究进展,主要对载体的形貌、载体的改性处理、茂金属催化剂的负载方法和负载化茂金属催化剂的应用进行了评述并展望了茂金属催化剂负载化的发展趋势。     

手性双(口恶)唑啉配体-金属配合物在催化不对称环丙烷化反应中的应用研究进展

将用于催化不对称环丙烷化反应中的手性双(口恶)唑啉配体按相应羧酸母体骨架分为丙二酸类,酒石酸类,吡啶二羧酸类,联苯、联萘及双核二茂铁类,将聚合物支载的双(口恶)唑啉配体单独进行了讨论.对各类配体的最新研究进展及其金属配合物在不对称环丙烷化反应中的应用作了总结.     

壳聚糖希夫碱铜多相催化剂的制备及其催化苯乙烯环丙烷反应的研究

采用均相和多相两种方法合成了壳聚糖希夫碱－Cu(Ⅱ)配合物，用于催化苯乙烯的不对称环丙烷反应，考察了不同制备方法和不同铜含量对催化剂催化性能的影响以及催化剂的重复使用情况，当催化剂的铜含量为4．4％时，得到20．7％的ee值。     

Silica-Based Supported Ionic Liquid-like Phases as Heterogeneous Catalysts

Supported ionic liquid phases offer several advantages related with catalysis. Immobilization of ionic liquid on the solid support provides catalytic activity or efficient matrix for active phases, as enzymes or metal compounds. Ionic liquid can be physically adsorbed on the carrier (supported ionic liquid phase) or chemically grafted to the material surface (supported ionic liquid-like phase). The use of supported ionic liquid phases improves mass transport, reduces ionic amount in the process and, most importantly, enables effortless catalyst separation and recycling. Moreover, chemical modification of the surface material with ionic liquid prevents its leaching, enhancing length of catalyst life. Silica-based materials have become an effective and powerful matrix for supported ionic liquid-like phase due to its cost-efficiency, presence of hydroxyl groups on the surface enabling its functionalization, and specific material properties, such as the size and shapes of the pores. For these reasons, supported ionic liquid-like phase silica-based materials are successfully used in the organic catalysis.     

Advances in Enzyme and Ionic Liquid Immobilization for Enhanced in MOFs for Biodiesel Production

Biodiesel is a promising candidate for sustainable and renewable energy and extensive research is being conducted worldwide to optimize its production process. The employed catalyst is an important parameter in biodiesel production. Metal–organic frameworks (MOFs), which are a set of highly porous materials comprising coordinated bonds between metals and organic ligands, have recently been proposed as catalysts. MOFs exhibit high tunability, possess high crystallinity and surface area, and their order can vary from the atomic to the microscale level. However, their catalytic sites are confined inside their porous structure, limiting their accessibility for biodiesel production. Modification of MOF structure by immobilizing enzymes or ionic liquids (ILs) could be a solution to this challenge and can lead to better performance and provide catalytic systems with higher activities. This review compiles the recent advances in catalytic transesterification for biodiesel production using enzymes or ILs. The available literature clearly indicates that MOFs are the most suitable immobilization supports, leading to higher biodiesel production without affecting the catalytic activity while increasing the catalyst stability and reusability in several cycles.