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聚己内酯(PCL)是一种生物可降解高分子材料,具有良好的环境、生物相容性,广泛应用于生物医学、包装等领域。有机小分子催化ε-己内酯单体开环聚合反应是制备聚己内酯的主要方式之一。与传统的金属催化相比,有机催化不仅反应条件温和、聚合可控,而且还可解决聚合物中金属残留问题,是目前高分子合成化学的研究热点。本文按照催化体系的不同活化方式,讨论了近年来有机催化在ε-己内酯开环聚合反应中的研究进展,归纳总结了不同催化体系的优缺点,并在此基础上展望了有机小分子催化剂在ε-己内酯开环聚合反应中的发展趋势和应用前景。 相似文献
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离子液体中氯化稀土催化ε-己内酯开环聚合 总被引:3,自引:0,他引:3
在离子液体中进行了无水氯化稀土催化ε-己内酯(ε-CL)的开环聚合,并考察了不同氯化稀土、环氧化物、环氧化物/氯化稀土摩尔比、单体浓度、单体/氯化稀土摩尔比、反应温度和时间对聚合的影响. 结果表明,无水氯化稀土/环氧化物能有效地催化ε-己内酯在离子液体中进行开环聚合, GdCl3和ErCl3的催化活性比其他稀土氯化物高.当温度为60 ℃, 环氧丙烷/ErCl3的摩尔比为30时, ε-CL 在离子液体[bmim]BF4中聚合30 min, 单体的转化率可达到96.0%, 粘均分子量(Mv)为2.54×104. 分别采用NMR和示差扫描量热对聚合物的结构和热性能进行了表征. 结果表明, ε-CL 在离子液体中发生了酰氧键断裂,聚合的机理是配位-插入机理. 相似文献
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以三氟甲烷磺酸亚锡为催化剂, 2-巯基乙醇为引发剂, 在温和条件下引发ε-己内酯的开环聚合, 得到端基为巯基的聚己内酯, 其分子量可控且分布较窄. 在此过程中, 巯基不需要保护而不会影响聚酯的结构, 当聚合温度升高时, 聚合物端基结构不发生改变, 但分子量分布变宽. 端基为巯基的聚己内酯能够通过偶合反应生成中间含二硫键的聚己内酯; 同时, 以2-羟乙基二硫化合物为引发剂合成得到分子中间含二硫键的窄分布聚己内酯, 经还原后也可得到端基为巯基的聚己内酯. 这两种方法条件温和, 效率较高, 具有良好的可控性. 相似文献
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三(2,6-二叔丁基-4-甲基苯氧基)镧配合物催化合成星形聚己内酯 总被引:2,自引:0,他引:2
分别以三乙醇胺和四乙醇乙二胺为引发剂,用三(2,6-二叔丁基-4-甲基苯氧基)镧(La(DBMP)3)作催化剂,催化ε-己内酯开环聚合,制备了三臂和四臂星形聚己内酯.通过1HNMR表征了聚合物的星形结构以及分子量.研究表明,每一个催化剂分子可与多个引发剂分子作用,当三乙醇胺与La(DBMP)3的摩尔比值为1.7~6.4时,均可制得纯净的三臂星形聚己内酯.通过调节ε-己内酯与多元醇的摩尔比值,可以改变星形聚己内酯的分子量,实现聚合产物分子量可控. 相似文献
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双羧基封端聚己内酯的合成与表征 总被引:5,自引:0,他引:5
在氮气氛中和丁二酸存在下,进行了ε-己内酯的开环聚合。IR, ̄1HNMR和 ̄(13)CNMR测定结果表明,聚合反应产物为双羧基封端的聚ε-己内酯。产物的分子量随二元酸用量的减少而增加,在酸/内酯摩尔比为1:14,225℃聚合3小时,产物的分子量达到最大值。 相似文献
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稀土化合物催化内酯开环聚合(Ⅲ)──氯化钕-环氧化合物体系催化ε-己内酯本体聚合申有青,沈之荃,沈建良,张富尧,张一烽(浙江大学高分子科学与工程学系,杭州,310027)关键词氯化钕,环氧化合物,ε-己内酯,本体聚合聚己内酯(PCL)和聚丙交酯(PL... 相似文献
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利用手持技术改进测定乙醇分子结构实验 总被引:1,自引:0,他引:1
利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。 相似文献
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V. I. Bol'shakova L. I. Demenkova É. N. Shmidt V. A. Pentegova 《Chemistry of Natural Compounds》1989,24(6):691-694
The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988. 相似文献
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Mustafa R. Ibrahim Zacharia A. Fataftah Paul von Ragu Schleyer Peter D. Stout 《Journal of computational chemistry》1987,8(8):1131-1138
Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases. 相似文献
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由于石化行业的生产需要,其材质的使用具有多样性和广泛性,经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识,根据光谱仪的测试能力及标样的采集,实现了一个或几个元素测量范围的扩展,并对其测量的影响因素进行了研究。 相似文献
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V. I. Bol'shakova L. I. Demenkova É. N. Shmidt V. A. Pentegova 《Chemistry of Natural Compounds》1988,24(6):691-694
The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae. 相似文献