Quantitative Characterization of Lewis Acidity and Activity of Chloroaluminate Ionic Liquids
Quantitative Characterization of Lewis Acidity and Activity of Chloroaluminate Ionic Liquids
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氯铝酸盐离子液体路易斯酸度和活性的定量表征
DOI：
10.1021/acs.iecr.6b02465
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发表时间：
2016-11-23
影响因子：
4.2
通讯作者：
Klusener, Peter A. A.
中科院分区：
文献类型：
--
作者：
Zhang, Xuan;Zhang, Rui;Klusener, Peter A. A.
吡啶可以作为形成不同类型键的布朗斯台德酸和刘易斯酸的基本指示剂。采用红外光谱结合27 Al核磁共振谱研究了吡啶与氯铝酸盐离子液体的相互作用机理。可以确定氯铝酸盐离子液体的酸类型、酸量、酸度甚至活性。采用原位红外络合滴定法对催化剂的酸性和活性进行了定量表征。该方法基于以下原理：刘易斯酸性氯铝酸盐[Al 2Cl 7]−与吡啶反应形成[AlCl 4]−阴离子和吡啶-AlCl 3（[PyAlCl 3]）络合物，而布朗斯台德酸形成吡啶鎓盐。两种产物类型均显示红外光谱中吡啶峰的特征位移。
Pyridine can act as a basic indicator for both Bronsted and Lewis acids forming different types of bonds. Infrared spectroscopy, in combination with 27Al NMR spectroscopy, was employed to study the interaction mechanism of pyridine and chloroaluminate ionic liquids (ILs). The acid type, acid amount, acidity, and even activity of chloroaluminate ILs could be determined. An in situ infrared complexometric titration was developed as a quantitative characterization method for determining the different acidities and catalyst activity. The method is based on the principle that Lewis acidic chloroaluminate [Al2Cl7]− anion reacts with pyridine to form the [AlCl4]− anion and pyridine–AlCl3 ([PyAlCl3]) complexes, while the Bronsted acid forms a pyridinium salt. Both product types showed characteristic shifts of the pyridine peaks in the infrared spectrum.