共查询到19条相似文献,搜索用时 65 毫秒
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杂多酸催化剂在有机合成中的应用 总被引:12,自引:3,他引:12
介绍了杂多酸催化剂在Friedel-Crafts酰基化和烷基化反应、Diels-Alder反应、酯化反应、环缩合反应、重排反应、溴化反应、氧化反应及不对称催化反应等有机合成反应中的应用。展望了该领域未来的研究方向。 相似文献
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近年来,硫酸氢钠(NaHSO4)作为一种稳定的、廉价的试剂,被广泛的应用在有机合成中。其可在不同的温和条件下高产率的催化氧化反应,C—O的形成与断裂等反应类型,根据硫酸氢钠的不同形式综述了其在有机合成中的其它新应用。 相似文献
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近年来,过渡金属催化的卤代芳烃与各种亲核试剂的偶联反应已成为构筑C―C或C―杂原子键的有效手段,例如著名的Suzuki、Kumada、Stille、Negishi等生成C―C键的偶联反应等。最近,C―H键的直接活化及功能化方面有了一些突破。介绍了这一领域的新进展。 相似文献
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二氧化硅负载高氯酸(HClO4/SiO2)作为非均相催化剂被广泛应用于各种有机反应中。主要综述了HClO4/SiO2催化Mannich反应、Friedlnder反应、Hosomi-Sakurai反应、Hantzsch反应以及α-氨基膦酸酯、β-烯胺酮(酯)和高烯丙基胺的合成等。同时对其今后的发展与应用前景进行了展望。 相似文献
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二氧化硅负载硫酸氢钠(NaHSO4/SiO2)是一种热稳定性好、简单易制、价格便宜、可循环使用的非均相催化剂。本文综述了近年来NaHSO4/SiO2在有机合成中的应用研究。NaHSO4/SiO2催化的有机反应具有操作简单、反应条件温和、清洁、高效以及后处理简单等优点。 相似文献
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Nafion-H SAC-13 solid superacid is shown to exhibit outstanding properties as catalyst in the formation of various protective groups. These include the formation of tetrahydropyranyl ethers of alcohols and the removal of this protective group, acetalization of carbonyl compounds with ethane-1,2-diol and propane-1,3-diol, and the transformation of aldehydes to 1,1-diacetates. Products are isolated in good to excellent yields and the catalyst can be reused with practically no loss of activity. 相似文献
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二硒醚在有机合成中的应用 总被引:1,自引:1,他引:0
综述了二烃基二硒醚的制备及其在有机合成中的应用,其中着重评述了有机硒正离子 RSe~+ 和有机硒负离子 RSe~- 在导入有机分子和有机官能团的修饰、变换中的作用。RSe~+ 和 RSe~- 可由相应的二硒醚制得。 相似文献
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Tine Rørvik Ivar M. Dahl Helle B. Mostad Ole Henrik Ellestad 《Catalysis Letters》1995,33(1-2):127-134
A solid superacidic Nafion-H polymer was examined as a catalyst for isobutane/2-butene alkylation and compared with a cerium-exchanged Y zeolite. Both catalysts demonstrate initial alkylation activity with rapid decrease in alkylation selectivity. The total product distributions were found to be significantly different after three hours of reaction. Nafion-H showed less selectivity towards iso-octanes, but formed relatively more 2,2,4-trimethylpentane. The differences between the two catalysts suggest dissimilar favoured reaction mechanisms. 相似文献
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Roland Wohlgemuth 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2007,82(12):1055-1062
The path to new chemical entities often shows the limitations of existing tools both in biocatalysis and organic chemistry. Organic synthetic procedures to prepare a compound in a target‐oriented synthesis can damage other functional parts of the molecule. Protection–deprotection schemes can lead to a dead end, when a certain protecting group cannot be cleaved off. In biocatalysis, on the other hand, the required biocatalytic toolbox and methodology might not be readily available, therefore limiting a biocatalytic approach. New toolboxes, ingredients, and methodologies at the interface of classical organic synthesis and biocatalytic reactions bridge the gap between these two areas. Since product isolation and purification involves a substantial amount of time in the preparation of chemicals, methodologies to simplify these tasks are necessary to get the pure product into the bottle with less work‐up time. Efficient and safe new pharmaceuticals, intermediates and analytical reagents need to be prepared under certain safety, health, environmental and economical boundary conditions. Biocatalytic reactions have been shown to overcome these limitations successfully and are becoming increasingly important in industrial manufacturing. Building bridges between biocatalysis and organic synthesis will therefore create roads to new synthetic strategies and technological frontiers of both fundamental and practical interest. Copyright © 2007 Society of Chemical Industry 相似文献
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综述了近年来以分子筛制备固体碱催化剂的研究进展,包括X型、Y型、L型等微孔分子筛和MCM-41、SBA-15等介孔分子筛经改性得到的固体碱,以及分子筛固体碱催化剂在双键异构化、酯化、酯交换、Knoevenagel缩合、Aldol缩合和Michael加成等有机反应中的应用。 相似文献