一元取代苯邻、间、对位亲电取代反应活性的几种判据

Some Criterions of the Electrophilic Substitution Reactivity at the Ortho, Para and Meta Position of the Mono-substituted Benzenes

以分子轨道理论为基础,系统介绍了π电荷密度法、定域能法和前线电子密度法等三种用于预测一元取代苯进行亲电取代反应时邻、间、对位的相对反应活性及反应产物的方法。采用自编程序分别计算了一些常见一元取代苯的π电荷密度、定域能和前线电子密度,得到的数据与这些化合物进行亲电取代反应时的相对活性及产物分布能较好的符合。并对这三种方法间的联系和三种方法的进展进行了讨论。

Based on the molecular orbital theories, three kinds of methods are systematically introduced, such as the π charge density method, localization energy method and frontier electron density method, which are used in predicting the reactivity at the ortho, para and meta position of the mono-substituted benzenes. A computer program is written to calculate the π charge density, localization energy and frontier electron density of some usual mono-substituted benzenes. The calculated results are in good agreement with the observed values. The relationship in these three kinds of methods and the progress of these methods are also discussed.