沸石
乙烯
催化作用
复分解
吸附
烯烃复分解
化学
碳-13核磁共振
烯烃纤维
无机化学
物理化学
立体化学
有机化学
聚合
聚合物
作者
Xiujie Li,Weiping Zhang,Shenglin Liu,Xiuwen Han,Xinhe Bao
出处
期刊:Journal of Molecular Catalysis A-chemical
[Elsevier]
日期:2006-05-01
卷期号:250 (1-2): 94-99
被引量:35
标识
DOI:10.1016/j.molcata.2006.01.046
摘要
The interfacial interaction of Mo species with the HBeta zeolite was studied by multinuclear MAS NMR, XRD and N2 adsorption. As proved by the quantitative 27Al MAS NMR, this interaction is so strong as to dealuminate the framework of HBeta, and leads to a new peak appearing at −14 ppm, which indicates the formation of crystalline Al2(MoO4)3. This can also be detected by XRD measurements when the Mo loading is as high as 9.0 wt.%. The corresponding quantitative 29Si and 1H MAS NMR spectra show that the amount of silanols and Brønsted acidic sites decrease obviously with increasing Mo loading. This also reveals an interaction between Mo species and HBeta support through an oxygen bridge resulting from condensation with the hydroxyls on the support. At higher Mo loadings, the interaction is so strong that it results in an extraction of aluminum from the zeolite framework, and subsequently appearance of Al2(MoO4)3 and loss of Brønsted acidic sites. These can be correlated to the low catalytic activity of Mo/HBeta in metathesis of ethylene and 2-butylene to propylene.
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