975 resultados para mesoporous MCM-41


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合成出了担载稀土有机配合物的无机 -有机杂化中孔发光材料 ( phen) 2 Eu/MCM-4 1 ,用 X射线衍射、红外光谱、荧光光谱和紫外 -可见漫反射光谱对所得样品进行了表征 ,并与相应的纯稀土配合物进行了比较 .结果表明 ,所得杂化材料具有典型的中孔材料 MCM-4 1的结构 ,且经组装后孔结构保持不变 ,在紫外光照射下 ,发出稀土离子的特征谱线 ,但与纯稀土配合物相比 ,其激发光谱发生蓝移 ,稀土 Eu3+ 所处的格位对称性降低 ,荧光寿命延长 .另外 ,对光谱性质进行了讨论 .

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Ferric trisacetylacetonate has been deposited within the zeolite MCM-41 and the product characterized by XRD and IR. In water at pH 7 it catalyzes the oxidation of phenol by H2O2, giving 58% conversion in 1 h at 50 degrees C: products are catechol (66%), hydroquinone (27%) and benzoquinone (7%). Other oxidants and solvents are much less effective. UV-VIS spectra suggest a radical substitution mechanism, and a pollution-free process for phenol hydroxylation is now possible.

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Iron(II)-8-quinolino/MCM-41 is prepared. Its catalysis is studied in phenol hydroxylation using H2O2 (30%) as oxidant. The experiment shows that Iron(II)-8-quinolinol/MCM-41 has good catalytic activity and desired stability. Based on cyclic voltammetry, ESR, and UV-visible spectra studies of iron(II)-8-quinolinol complex in liquid phase, a radical substitution mechanism is proposed and used to demonstrate the experimental facts clearly. (C) 1997 Academic Press.

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利用MCM-41中孔分子筛为载体,制备了负载型八羟基喹啉铁(Ⅱ)/MCM-41(简记为Fe(Ⅱ)-Qx/MCM-41)催化剂.XRD,IR证明八羟基喹啉铁(Ⅱ)配合物成功地负载于MCM-41分子筛中.考察了八羟基喹啉铁(Ⅱ)/MCM-41对苯酚羟化反应的催化作用,和未负载的配合物相比,苯酚的转化率、对苯二酚的选择性以及H2O2的利用率都有显著的提高.同时也探讨了温度、反应介质及介质pH值对苯酚羟化反应的影响.结果表明,随着温度的提高,苯酚的转化率增加,但温度太高,易导致副产物增多;有机溶剂不利于羟化反应的进行,水是实验条件下苯酚羟化反应的最佳反应介质;在一定程度上,pH值越低,越有利于反应活性的提高,若pH值太低,活性反而下降,pH值升高不利于苯酚羟化反应的进行.该催化剂也具有较高的稳定性.

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MCM-41 zeolite and Tron (II)-Phen/MCM-41 zeolite have been prepared and characterized by XRD, IR, NH3-TPD, HET and UV-Vis. The Iron( II)-Phen/MCM-41 zeolite+30% H2O2 system is capable for catalyzing hydroxylation of phenol.

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MCM-41分子筛是最近美国Mobil公司开发出的一种新材料,其孔径范围在2.0~25nm之间,具有较大的Si/Al比和大的比表面积及孔隙率,孔道大小均匀.其对弱极性的环状及芳族化合物具有较大的吸附能力.自这种新型分子筛合成以来,才开始应用于石油炼制及烯烃裂解,歧化的研究.至今还没有关于将MCM-41作为载体,用于负载金属配合物催化剂的报道.本文利用自己合成的MCM-41分子筛作为载体,制成了负载铁的1,10-菲咯啉配合物催化剂(简记FePhen/MCM-41),并将其应用于苯酚的羟化反应,发现其对苯酚的羟化反应具有较好的催化性能.1 实验部分1.1 FePhen/MCM-41的制备将参考文献[3]制得的MCM-41分子筛,取5g放入200mL0.05mol/L的[Fe(Phen)_3]Cl_2乙醇溶液中,室温搅拌24h,抽滤,所得固体用乙醇洗涤3次,以除去MCM-41分子筛表面和孔道内结合不牢的金属配合物.利用原子吸收光谱分析仪,测得负载催化体系中铁元素的含量为0.65%.1.2 MCM-41分子筛及FePhen/MCM-41的表征