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Synthesis of mesoporous molecular sieves: influence of aluminum source on Al incorporation in MCM-41 总被引:1,自引:0,他引:1
Three series of mesoporous aluminosilicate molecular sieves, MCM-41, with various Si/Al ratios were synthesized using different aluminum sources (aluminum isopropoxide, pseudo boehmite and aluminum sulfate). XRD analysis, temperature programmed desorption ofn-butylamine,27Al and29Si MAS NMR, and catalytic alkylation test indicated that aluminum isopropoxide is a better source for incorporating aluminum in the framework of MCM-41 type molecular sieves with better crystallinity and acid characteristics. 相似文献
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Takashi Tatsumi Keiko A. Koyano Yoshinori Tanaka Shinichi Nakata 《Journal of Porous Materials》1999,6(1):13-17
The structural collapse of mesoporous molecular sieves, MCM-48 and MCM-41 materials by mechanical compression was found to occur mechanochemically through hydrolysis of Si–O–Si bonds. Their ordered structures were retained by compressing the well-dried samples under dry N2. Trimethylsilylation of mesoporous materials proved effective in eliminating their instability to compression through enhancing hydrophobicity. 相似文献
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Ayyamperumal Sakthivel Sushanta K. Badamali Parasuraman Selvam 《Catalysis Letters》2002,80(1-2):73-76
Liquid-phase catalytic oxidation of certain alkylaromatics over mesoporous (Cr)MCM-41 molecular sieves in the presence of chlorobenzene and tertiary butylhydroperoxide showed high substrate conversion and excellent product selectivity. The high catalytic activity of the materials is attributed to the complete oxidation of chromium ions to hexavalent chromium and the absence of pentavalent chromium in the mesoporous matrix. 相似文献
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MCM-41介孔分子筛改性研究进展 总被引:1,自引:0,他引:1
介绍了有序介孔材料的定义和分类,MCM-41介孔分子筛、合成方法和形成机理,针对其MCM-41目前存在的一些问题,综述了国内外对MCM-41介孔分子筛最新的改性研究进展。 相似文献
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Mesoporous (Cr)MCM-41 and (Cr)MCM-48 Molecular Sieves: Promising Heterogeneous Catalysts for Liquid Phase Oxidation Reactions 总被引:1,自引:0,他引:1
Ayyamperumal Sakthivel Sudhir E. Dapurkar Parasuraman Selvam 《Catalysis Letters》2001,77(1-3):155-158
Chromium-containing mesoporous MCM-41 and MCM-48 silicate molecular sieves were synthesized and characterized. Unlike the chromium-containing microporous materials, the mesoporous analogues show significant activity for the chosen (ethylbenzene oxidation) reaction even after several recycling or washing treatments. 相似文献
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全硅MCM-41中孔分子筛的合成 总被引:9,自引:0,他引:9
在碱性条件下,采用水热晶化法,以水玻璃为硅源,表面活性剂十六烷基三甲基溴化铵为结构模板剂,成功合成出全硅MCM-41中孔分子筛。采用X射线衍射分析研究了合成条件(pH值)、凝胶配比(表面活性剂/SiO2、H2O/SiO2)和凝胶后处理条件(老化时间、晶化温度、晶化时间和焙烧温度)对MCM-41结构的影响。结果表明全硅MCM-41的合成条件为pH10.5-12.5,表面活性剂/SiO20.05-0.7,H2O/SiO2 40-200,老化时间长对合成晶形较的全硅MCM-41有利。晶化温度70℃-100℃,晶化时间24小时,焙烧温度540℃-740℃。 相似文献
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以铈掺杂介孔分子筛MCM-41作为催化剂,并用于催化合成柠檬酸三丁酯。研究表明Ce-MCM-41在合成柠檬酸三丁酯中具有良好的催化性能:当n(柠檬酸)∶n(正丁醇)=1∶5.0;w(cat)%=5%;反应温度140℃;反应时间7 h,酯化率为91.2%,催化剂可重复使用。 相似文献
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介孔分子筛MCM-41的合成探索 总被引:1,自引:0,他引:1
以正硅酸乙酯(TEOS)为硅源、十六烷基三甲基溴化铵(CTAB)为模板剂,利用水热合成法制备了介孔氧化硅MCM-41,并采用TEM、XRD、N2吸附-脱附等测试手段对产物进行了表征。结果表明,合成的介孔材料为高质量的MCM-41。 相似文献
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以苄基磺酸化MCM - 41介孔分子筛(SBM)为催化剂,催化合成柠檬酸三丁酯.研究结果表明,SBM在合成柠檬酸三丁酯的反应中具有良好的催化性能,当n(酸):n(醇)=1.0:8.0,w(cat)%=3%,反应时间7h,酯化率为93%,且催化剂重复4次后转化率为76.3%. 相似文献
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Transesterification Catalyzed by Trypsin Supported on MCM-41 总被引:2,自引:0,他引:2
J.M. Gómez J. Deere D. Goradia J. Cooney E. Magner B.K. Hodnett 《Catalysis Letters》2003,88(3-4):183-186
Trypsin supported on MCM-41 is demonstrated as a stable catalyst for the transesterfication of N-acetyl-L-tyrosine ethyl ester with propan-1-ol. An enzyme loading of 5 micromoles of trypsin per gram of silicate was readily achieved. The ultimate enzyme loading was shown to depend strongly on enzyme purity. The adsorbed enzyme exhibited the same turnover frequency for the transesterification reaction as native trypsin, the catalyst could be reused without loss of activity following separation by centrifuging and the enzyme did not leach during testing. 相似文献
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MCM-41介孔分子筛研究进展 总被引:1,自引:0,他引:1
介绍了介孔材料的定义,总结了MCM-41介孔分子筛的合成方法,针对其目前存在的孔径较小及酸性较小的缺点,综述了国内外对MCM-41介孔分子筛的孔径扩大分的最新研究进展。 相似文献
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实验以亚甲基蓝作为模型吸附质,探讨了MCM-41介孔分子筛对模型吸附质亚甲基蓝的吸附性能,并对其吸附过程进行了热力学和动力学分析。结果表明,MCM-41介孔分子筛的吸附率高达94%,对亚甲基兰的吸附符合二级吸附动力学,MCM-41对亚甲基兰的吸附行为属于Freundlich等温吸附,整个吸附过程属于放热反应。 相似文献