共查询到20条相似文献,搜索用时 78 毫秒
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开环易位聚合(ROMP)是一种单环或多环烯烃进行开环聚合反应形成功能化聚合物的方法, 已经发展成为一种合成先进聚合物材料的高效方法之一. 而星型聚合物由于特殊的结构和性能将在学术和工业的材料科学和纳米技术领域中发挥越来越重要的作用. 本综述从聚合方法、聚合单体、引发剂、交联剂等方面讨论了ROMP在星型聚合物合成中的应用, 并介绍了ROMP合成的星型聚合物的应用领域和前景, 客观地评价了各种ROMP方法的优势和局限性. 这项工作旨在促进ROMP在合成星型聚合物的研究, 为合成功能性复杂星型聚合物提供新的科学研究途径, 为加快星型聚合物材料商业化的脚步添砖加瓦. 相似文献
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与传统线形聚合物的合成不同,环状聚合物的合成通常需要特殊的催化剂设计且容易引入主体单体以外的其他化学结构.最近,吉林大学张越涛团队将两分子硼路易斯酸(LA)与一分子磷路易斯碱(LB)以共价键相连,合成出分子内受阻路易斯酸碱对B-P-B三官能催化剂,通过分子内和分子间的双重协同作用实现了1+1>>2的催化效果,进而成功以γ-甲基-α-亚甲基-γ-丁内酯(MMBL)为单体合成了完全由一种丙烯酸酯类单体构成的环状聚合物c-PMMBL.值得指出的是,与合成环状聚合物的传统策略不同,该催化剂可以在较高浓度下简单快速地合成环状聚合物,开创了环状聚合物宏量高效合成的新路线. 相似文献
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印迹聚合物合成条件对聚合物性能的影响是分子印迹技术中的一项重要研究内容。以左旋麻黄碱为印迹分子,甲基丙烯酸为功能单体,使用不同的交联剂和致孔剂合成了印迹聚合物,并对所得到的印迹聚合物的比表面积、孔结构和结合特性进行了评价。研究结果说明合成的印迹聚合物对印迹分子具有很好的亲和能力及选择性。致孔剂可以影响聚合物比表面积的大小及单体组成。氯仿是甲基丙烯酸-乙二醇二甲基丙烯酸酯和甲基丙烯酸-季戊四醇三丙烯酸酯聚合链的良溶剂,导致了比表面积及孔容较小的聚合物结构;而以乙腈为致孔剂得到的聚合物有较大的比表面积。共聚物中羧基含量的测定结果也说明,在预聚溶液中单体浓度相同的条件下,以不同的致孔剂进行合成得到的聚合物中甲基丙烯酸的比例不同。聚合物的比表面积及单体浓度的差别都可能导致聚合物的结合容量不同。 相似文献
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环状聚合物具有不同于线性高分子的独特性质,是一类具有应用前景的新型聚合物材料,但复杂的结构导致其合成过程复杂繁琐."点击"化学由于其高效、可靠、高选择性的特点已成为拓扑高分子合成的新方法,活性自由基聚合(ATRP、RAFT和NMP)具有聚合物结构可控等特点,二者联用为环状聚合物的合成拓宽了思路.本文就近几年"点击"反应、"点击"反应与活性自由基聚合联用以及其他方法联用在环状聚合物中的应用进行综述."点击"反应与这些方法的结合将在功能性环状聚合物的设计与合成中发挥积极的作用. 相似文献
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代莉莉 《分析测试技术与仪器》2022,28(4):375-383
基质辅助激光解析电离飞行时间质谱(MALDI-TOF-MS)在合成聚合物的表征手段中具有不可替代的优点,可以提供聚合物的质量分布、嵌段长度、端基等信息.但由于合成聚合物的离子化效率通常不佳,因此样品制备是分析成功的关键.从基质、基质添加剂以及混样方式3个方面综述了MALDI-TOF质谱分析合成聚合物样品制备的研究进展. 相似文献
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2,3-联烯醇是一类含1,2-二烯官能团和羟基的化合物, 具有很高的反应活性, 它及其衍生物是一类重要的联烯化合物. 概述了2,3-联烯醇及其衍生物的反应, 包括2,3-联烯醇在过渡金属催化下的自身异构环化反应、钯催化的偶联反应、钌催化的环羰基化反应、不同条件下不同方式的扩环反应、亲电试剂参与的反应、分子内环加成反应、自由基反应等和2,3-联烯醇衍生物在零价钯催化下基于亚甲基-π-烯丙基钯中间体生成联烯或1,3-共轭二烯的区域选择性反应, SN2'类型的加成-消除反应, 二价钯催化下的分子内环化反应以及重排反应等. 相似文献
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Iwao Omae 《Journal of organometallic chemistry》2007,692(13):2608-2632
There are three types of reactions with intramolecular five-membered ring compounds in organic syntheses: The first type is reactions involving intramolecular five-membered ring compounds which are utilized for the ease of synthesis of these compounds and the stability of the products. The second is reactions performed via intramolecular five-membered ring intermediates, because such intermediates are very reactive and labile compounds. The third is the metal-catalyzed reactions with the intramolecular five-membered ring compounds because these metal compounds have catalytic activities. The third type reactions involving intramolecular five-membered ring pincer compounds are also provided.The first type reactions include carbonylations, alkenylations, alkynylations, acylations, isocyanations, Diels-Alder reactions, etc. The second type reactions include carbonylations, cross-coupling reactions, hydroacylations, ring expansion reactions, carbocyclizations, etc. The third type reactions include cross-coupling reactions, rearrangements, metatheses, reductions, Michael reactions, dehydrogenations, Diels-Alder reactions, etc. 相似文献
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Mischmetall, an alloy of the light lanthanides, has been used in a variety of organic reactions, either as a coreductant in samarium(II)-mediated reactions (Barbier and Grignard-type reactions, pinacolic coupling reactions) or as the promoter of Reformatsky-type reactions. It has been also employed as the starting material for easy syntheses of lanthanide trihalides, the reactivity of which has been explored in Imamoto and Luche–Fukuzawa reactions and in Mukaiyama aldol reactions. 相似文献
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Chemical kinetics of reactions in the unfrozen solution of ice 总被引:1,自引:0,他引:1
Some reactions are accelerated in ice compared to aqueous solution at higher temperatures. Accelerated reactions in ice take place mainly due to the freeze-concentration effect of solutes in an unfrozen solution at temperatures higher than the eutectic point of the solution. Pincock was the first to report an acceleration model for reactions in ice,1 which successfully simulated experimental results. We propose here a modified version of the model for reactions in ice. The new model includes the total molar change involved in reactions in ice. Furthermore, we explain why many reactions are not accelerated in ice. The acceleration of reactions can be observed in the cases of (i) second- or higher-order reactions, (ii) low concentrations, and (iii) reactions with a small activation energy. Reactions with a buffer solution or additives in order to adjust ion strength, zero- or first-order reactions, or reactions containing high reactant concentrations are not accelerated by freezing. We conclude that the acceleration of reactions in the unfrozen solution of ice is not an abnormal phenomenon. 相似文献
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Chun‐Xiang Zhuo Prof. Dr. Wei Zhang Prof. Dr. Shu‐Li You 《Angewandte Chemie (International ed. in English)》2012,51(51):12662-12686
This Review summarizes the development of catalytic asymmetric dearomatization (CADA) reactions. The CADA reactions discussed herein include oxidative dearomatization reactions, dearomatization by Diels–Alder and related reactions, the alkylative dearomatization of electron‐rich arenes, transition‐metal‐catalyzed dearomatization reactions, cascade sequences involving asymmetric dearomatization as the key step, and nucleophilic dearomatization reactions of pyridinium derivatives. Asymmetric dearomatization reactions with chiral auxiliaries and catalytic asymmetric reactions of dearomatized substrates are also briefly introduced. This Review intends to provide a concept for catalytic asymmetric dearomatization. 相似文献
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Fluorinated alcohols have been widely used in the synthetic organic chemistry over the past decades. The unique properties such as the strong hydrogen‐bonding donor ability and low nucleophilicity allow them to promote organic reactions in the absence of any catalyst. These approaches have distinct advantages in terms of operational simplicity, practicability and environmental friendliness. Reactions promoted by fluorinated alcohols, including nucleophilic substitution reactions, annulation reactions, electrophilic reactions, dearomatization reactions, functionalization of multiple bond, epoxidation reactions and miscellaneous reactions have been summarized in this account. 相似文献
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迄今为止,贵金属(铑、钯、钌等)在过渡金属催化的碳碳键生成反应中发挥着主导作用,然而使用廉价金属催化剂更符合可持续发展的要求。锰是地壳中含量排第三位的过渡金属,价格便宜,环境危害性小,有潜力成为贵金属催化剂的替代品并发挥其自身独特的反应性。尽管锰参与的当量反应有大量文献报道,目前锰催化的反应尤其是碳碳键生成反应的发展还不成熟,如何实现高效的催化循环是锰催化领域面临的主要难题之一。本文对锰催化的付-克烷基化反应、格氏试剂的酰化反应、偶联反应、碳金属化反应、自由基反应和碳氢键活化反应进行了综述。 相似文献