共查询到19条相似文献,搜索用时 281 毫秒
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为了避免挥发性有机溶剂造成环境污染,研究了无溶剂条件下的Knoevenagel缩合反应。以功能性离子液体乳酸乙醇胺盐作催化剂,在无溶剂条件下实现了苯甲醛、甲基苯甲醛、甲氧基苯甲醛、氯代苯甲醛和呋喃醛等芳香醛与氰基乙酸乙酯或丙二腈的Knoevenagel缩合反应。反应在室温条件下,数分钟至1 h内完成,收率81%~98%。反应选择性好,只生成E-烯烃,产物分离过程简便,通过简单的乙醇水溶液洗涤和重结晶即可分离出产物。初步讨论了功能性离子液体乳酸乙醇胺盐催化的Knoevenagel缩合反应机理。 相似文献
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研究了离子液体中芳香醛和丙二酸亚异丙酯之间的Knoevenagel反应,发现在乙二胺二乙酸盐(EDDA)催化下缩合反应能在室温下短时间内顺利完成,产物分离方便,离子液体和固定在其中的催化剂可以循环利用,效果良好。 相似文献
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离子液体由于具有特殊的性质,包括挥发性低、极性大、良好的热稳定性、通过调整阴阳离子选择不同的溶解性等特点,已经作为反应介质或催化剂广泛应用于有机合成领域,引起了人们足够的兴趣.与传统有机溶剂反应相比,离子液体相反应得到的产物收率高,选择性好,加快部分类型反应的速率,后处理简单以及离子液体催化剂体系简单,回收后,可多次重复使用.本文综述了离子液体作为反应介质或催化剂在有机合成传统反应类型中的最新研究成果,主要包括:氧化还原反应、Beckmann重排反应、偶联反应、Diels- Alder反应、氢甲酰化反应、Knoevenagel缩合、烷基化及Blanc氯甲基化反应. 相似文献
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制备了活性炭固载溴化1-(2-胺乙基氢溴酸)-3-甲基咪唑翁盐离子液体催化剂,并用TG和XPS对催化剂进行了表征。将该催化剂首次用于Knoevenagel缩合反应,结果表明活性炭固载离子液体催化剂具有良好的催化活性和稳定性,同时克服了均相催化剂难以分离的不足。 相似文献
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离子液体在有机反应中的应用 总被引:1,自引:0,他引:1
室温离子液体,由含氮的有机阳离子和无机阴离子组成,由于离子液体是很多化合物的溶剂,也能够溶解作为催化剂的过渡金属络合物,其阴离子还是潜在的配位体,故它们能起催化剂的功能,本文着重讨论这方面的发展状况。 相似文献
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Different types of microstructures and their applications with respect to the synthesis and the use of ionic liquids are presented. Microstructured reactors are suitable for reactions with fast intrinsic kinetics, requiring high mass and heat transfer performances. Chemical synthesis can be performed safely under operating condition (e.g. high temperature, pressure, etc.) difficult to obtain in traditional reactors. The examples presented clearly indicate that microstructured reactors offer superior performance for the synthesis of ionic liquids in comparison to conventional equipment. For the use of ionic liquids as reaction media, existing ionic liquids show some limitations due to their higher viscosity compared to conventional solvents. Therefore, future research should be focused on the development of low viscosity ionic liquids.The approaches to use ionic liquids in microstructured reactors and in combination with microstructured supports for catalytic reactions show many advantages in view of high product selectivity and yield. The use of supported ionic liquids on microstructured materials seems to be particularly promising for gas phase as well as for gas/liquid reactions. 相似文献
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Fan Ouyang Yan Zhou Zhang-Min Li Na Hu Duan-Jian Tao 《Korean Journal of Chemical Engineering》2014,31(8):1377-1383
Five tetrabutylphosphonium amino acid ionic liquids ([P4444][AA]) were prepared, characterized, and used as catalysts for solvent-free Knoevenagel condensation reactions. The tetrabutylphosphonium prolinate ([P4444][Pro]) showed excellent catalytic activity and selectivity in Knoevenagel condensation reactions of active methylene compounds with various aromatic aldehydes, and all the yields of corresponding products were more than 85% under mild conditions. Furthermore, a plausible reaction mechanism for the excellent performance of [P4444][Pro] has been proposed, and [P4444][Pro] could be used repetitively at least six times without obvious decrease in activity and quantity. 相似文献
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离子液体在有机合成中的应用新进展 总被引:1,自引:0,他引:1
室温下的离子液体作为一种绿色、环保、可替代传统有机溶剂的新型溶剂受到了极大关注.总结了近年来离子液体在有机合成反应中的研究新进展,包括氧化反应、还原反应、Friedel-Crafts反应、Diels-Alder反应、Heck反应、硝化反应及其它合成反应. 相似文献