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Cai Qin QIN Ling XIAO Yu Min DU* Department of Environmental Science Wuhan University Wuhan 《中国化学快报》2001,(12)
Borohydride exchange resin (BER) a useful reducing reagent has been used in reduction of some carbonyl compounds and acyl halides1. When BER combines with a transition metal catalyst, it can reduce C=C double bonds2, halides2, nitro compounds3, cyano, diazo3 and azide compounds4. The support of BER is the synthetic macromolecule polystyrene. Here, we used chitosan as the support of borohydride. As known, chitosan is a renewable and abundant natural polysaccharide. Scheme 1 Preparat… 相似文献
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Yukihiro Arakawa 《Tetrahedron letters》2006,47(19):3239-3243
New polymer-supported chiral sulfonamides containing sulfonated pendant group have been synthesized. Chiral catalyst prepared from the new polymer-support is more effective for asymmetric transfer hydrogenation of aromatic ketones in water compared to that prepared from conventional polystyrene-support. Polymer-supported catalysts containing quaternary ammonium salt as a pendant increased not only the reactivity but also the enantioselectivity in asymmetric transfer hydrogenation in water. Moreover, this type of polymer can be reused without loss of the catalytic activity. 相似文献
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PreparationandCharacterizationofPolymer-SupportedRareEarthComplexesYUGuang-qianandLIYu-liang(ChangchunInstituteofAppliedChemi... 相似文献
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Guang Qian YU* De Ze ZHANG Fu SHUN Li Jun QIAO Tao TANG Bao Tong HUANG State Key Laboratory of Polymer Physics Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences Polymer Chemistry Laboratory Chemistry Academy of S 《中国化学快报》2001,(3)
Although homogeneous metallocene catalysts show some specific characteristics, such as single site, extremely high catalytic activity, high ability to incorporate monomers, narrow molecular weight and comonomer distribution, and excellent control of stereoregularity, but they also suffer some drawbacks, a very large amount of MAO requirement, inability to be used in slurry or gas phase processes, and poor control of polymer morphology. Therefore, it is necessary to modify the catalysts for the… 相似文献
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