共查询到18条相似文献,搜索用时 62 毫秒
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采用新的微波固相法制备出Mn(Salen)/Al-HMS催化剂.通过FTIR和TG的表征,结果表明,微波固相方法成功地将Mn(Salen)配合物固载于介孔Al-HMS分子筛中.以苯乙烯环氧化反应为例比较了不同方法制备的催化剂的催化性能,发现微波固相法制备的Mn(Salen)/Al-HMS-IP催化剂具有较高的催化活性和最好的环氧化物选择性,此外,考察了催化剂性能还与制备过程中的微波辐射时间、反应时间、反应溶剂、反应温度、氧化剂的用量及催化剂的重复使用对微波固相法制备的催化剂的性能影响规律,得到了满意的结果. 相似文献
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报道了一种新的微波固相法制备Mn(Salen)/Al-MCM-41催化剂的方法,并与常规制备方法进行了比较。对微波固相法制备的催化剂进行了一系列的表征,表征结果表明,微波固相方法和常规方法均能成功地将Mn(Salen)络合物固载于介孔Al-MCM-41分子筛中,且在原料的量相同的情况下,红外光谱显示微波固相法具有更强的吸收峰。比较了不同方法制备的催化剂在苯乙烯环氧化反应中的催化性能,发现微波固相法制备的Mn(salen)/Al-MCM-41-IP催化剂具有较高的催化活性和最好的环氧化物选择性。还考察了催化剂性能与制备过程中的微波辐射时间的关系。进行了催化剂的重复使用的实验,使用三次后,转化率达到59.4%,选择性可达78.3%。 相似文献
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用微波固相法制备了Mn(Salen)/NaY催化剂, 并对其催化β-蒎烯环氧化反应的性能进行了考察。FT-IR结果表明,微波固相方法和常规方法均能成功地将Mn(Salen)络合物包合于微孔分子筛NaY。与常规法制备的催化剂相比,微波固相法制备的Mn(Salen)/NaY催化剂对β-蒎烯环氧化具有很高的转化率和选择性,并且重复使用后催化活性变化不大。 相似文献
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针对不同无机材料载体和固载方法,综述了近几年无机材料固载Mn(Salen)催化剂的研究进展。重点介绍了二氧化硅、分子筛、活性炭、溶胶凝胶固载手性Mn(Salen)催化剂的特点及性能,并对固载手性Mn(Salen)催化剂存在的问题和前景进行了分析。 相似文献
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聚苯乙烯负载Salen-Mn(Ⅲ)配合物的制备及其催化空气环氧化烯烃反应 总被引:1,自引:0,他引:1
Salen Mn(III)配合物是空气环氧化烯烃的优良均相催化剂.然而,与反应混合物难于分离的缺点限制了其大规模地使用,利用高聚物为载体负载此类配合物有望解决这一问题.因此,通过多步接枝法将一Salen-Mn(Ⅲ)配合物负载在聚苯乙烯(交联度2%)树脂上制备了高分子负载的催化剂. 利用傅立叶变换-红外光谱、原子吸收以及元素分析等方法对该催化剂及其前体进行了表征.分别以环己烯, 苯乙烯, 1-辛烯为底物考察了该负载配合物催化空气环氧化烯烃反应的性能;考察了环氧化反应条件对催化剂性能的影响, 并得出优化的环氧化反应条件.在此条件下环己烯的转化率可达91.4%, 环氧环己烷的选择性达86.3%.同时在优化条件下考察了催化剂的循环使用性能.上述结果表明该负载催化剂对环己烯和苯乙烯的空气环氧化具有很高活性和环氧化物选择性.该催化剂能够循环使用几次,但未达到预期效果. 相似文献
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Dongmin Zhao Jiquan Zhao Shanshan Zhao Weiyu Wang 《Journal of Inorganic and Organometallic Polymers and Materials》2007,17(4):653-659
A chiral Manganese (III) salen complex was immobilized on the walls of MCM-41 (mobile crystalline material) through the multi-grafting
method. The immobilized complex was characterized by XRD, FTIR, UV-Vis, ICP and Nitrogen sorption, and was applied to the
asymmetric epoxidation of unfuctionalized alkenes including 1,2-dihydronaphthalene, α-methylstyrene, cis-β-methylstyrene, styrene using NaClO and m-chloroperbenzoic acid (m-CPBA) as oxidants respectively. The immobilized complex showed good activity and enantioselectivity in the epoxidation of
1,2-dihydronaphthalene by using NaClO as oxidant. It could also be run for 4 times in the epoxidation of α-methylstyrene without
obvious loss of activity or enantiomeric excess. 相似文献
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B.M. Choudary N. Sreenivasa Chowdari M. Lakshmi Kantam P. Lakshmi Santhi 《Catalysis Letters》2001,76(3-4):213-218
Heterogeneous Mn(III) chiral salen complexes are prepared through covalent attachment of salen ligand on silica gel via chloropropyl spacer and subsequent complexation with manganese. The complexes are well characterized by IR, UV/VIS, TGA and elemental analysis. Epoxidation of unfunctionalised prochiral olefins by Mn(III) chiral salen complexes using iodosobenzene and m-CPBA as the terminal oxidants and NMO as a co-oxidant was achieved with good yields albeit low enantiomeric excess. 相似文献
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New dendritic catalysts have been prepared by the immobilization of a Mn(II) salen complex on a polyamidoamine dendrimer propagated on the surface of silica. These have been applied in the catalytic epoxidation of olefins. Although the increase of the amount of Mn loading is found to be limited on high-generation dendrimers, the Mn(II) salen complex anchored on the fourth-generation dendrimer shows much higher catalytic activity toward the epoxidation of styrene than that anchored on lower generations. These results suggest that the length of the dendritic backbone chain plays an important role in increasing the accessibility between the catalytic active sites of the immobilized Mn(II) salen complex and the reactant molecules, resulting in the enhancement of the catalytic activity of the Mn(II) salen complex anchored on the fourth-generation dendrimer. 相似文献
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Donglu Xiong Zaihui Fu Sheng Zhong Xiangfen Jiang Dulin Yin 《Catalysis Letters》2007,113(3-4):155-159
A series of novel non-salicylaldehyde based Salen ligands have been synthesized from the condensation of dialdehyde or diketone
with o-aminophenol and the corresponding manganese(III) complexes prepared by further coordination of them with . FT-IR, UV–Vis spectra, chemical analysis and the structure optimized by Hartree-Fork/3-21G+ all indicated that the qualities
of these novel Mn complexes were relative to their molecular structures. More specifically, glyoxal based Mn complex 2c, which
was similar to the traditional Mn(III)-salicylethylenediamine, had a short carbon chain and non geometrical constraint of
the aliphatic bridge in the two o-aminophenol, and its quality was the best when compared to glutaraldehyde, 2,4-pentanedione and 1,3-cyclohexanedione based
Salen Mn(III) complexes (3c, 4c and 5c). And it was also the excellent catalyst for the epoxidations of several non-functionalized
alkenes with molecular oxygen/sacrificial-isobutyaldehyde, PhI(OAc)2 or H2O2 as oxidant. 相似文献
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