Murthy J Krishna, Gross Udo, Rüdiger Stephan, Rao V Venkat, Kumar V Vijaya, Wander A, Bailey C L, Harrison N M, Kemnitz Erhard
Institute of Chemistry, Humboldt- University Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany.
J Phys Chem B. 2006 Apr 27;110(16):8314-9. doi: 10.1021/jp0601419.
Aluminum chloride is used extensively as Lewis acid catalyst in a variety of industrial processes, including Friedel-Crafts and Cl/F exchange reactions. There is a common misconception that pure AlCl3 is itself a Lewis acid. In the current study, we use experimental and computational methods to investigate the surface structure and catalytic properties of solid AlCl3. The catalytic activity of AlCl3 for two halide isomerization reactions is studied and compared with different AlF3 phases. It is shown that pure solid AlCl3 does not catalyze these reactions. The (001) surface of crystalline AlCl(3) is the natural cleavage plane and its structure is predicted via first principles calculations. The chlorine ions in the outermost layer of the material mask the Al3+ ions from the external gas phase. Hence, the experimentally found catalytic properties of pure solid AlCl3 are supported by the predicted surface structure of AlCl3.
氯化铝在包括傅克反应和氯/氟交换反应在内的各种工业过程中被广泛用作路易斯酸催化剂。有一种常见的误解，认为纯AlCl₃本身就是一种路易斯酸。在当前的研究中，我们使用实验和计算方法来研究固体AlCl₃的表面结构和催化性能。研究了AlCl₃对两种卤化物异构化反应的催化活性，并与不同的AlF₃相进行了比较。结果表明，纯固体AlCl₃不催化这些反应。结晶AlCl₃的(001)表面是天然解理面，其结构通过第一性原理计算得到预测。材料最外层的氯离子屏蔽了Al³⁺离子与外部气相的接触。因此，纯固体AlCl₃的实验发现的催化性能得到了AlCl₃预测表面结构的支持。
