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研究了一系列不同锌含量的ZSM-5样品的呲啶吸附红外光谱和芳构化性能。通过对1616cm~(-1)红外吸收带的定性和半定量处理,找出了样品的Brnsted酸,L_(1616)酸及正庚烷芳构化活性与样品锌含量的关系,比较了不同方法制备的ZnZSM-5的酸性和芳构化活性,用热重分析测定了HZSM-5和含锌ZSM-5的羟基含量。在实验结果的基础上提出了1616cm~(-1)所表征的活性中心是一个结构基团,它可由ZnO与ZSM-5上的酸性羟基作用形成,也可由交换进ZSM-5的水合锌离子解离形成,它是ZnZSM-5沸石上的芳构化活性中心。
A series of ZSM-5 samples with different zinc contents were investigated by pyridine adsorption IR and aromatization. The relationship between the aromatization activity of Brnsted acid, L 1616 acid and n-heptane and the zinc content in samples was found by qualitative and semi-quantitative treatment of the 1616cm -1 infrared absorption band The acidity and aromatization activity of ZnZSM-5 prepared by different methods were measured by thermogravimetric analysis for the hydroxyl content of HZSM-5 and zinc-containing ZSM-5. On the basis of the experimental results, it is proposed that the active center represented by 1616cm -1 is a structural group which can be formed by the interaction of ZnO with the acidic hydroxyl group on ZSM-5 and the zinc ion exchanged into ZSM-5 Dissociation formed, it is ZnZSM-5 zeolite active center of aromatization.