单取代芳烃的硝化

以甲苯、乙苯、异丙苯、叔丁基苯、氟苯等为硝化底物，通过混酸硝化得到这些单取代芳烃转化率最大时的混酸硝化强度φ。 运用密度泛涵理论，在B3LYP/6-311G**水平上优化了9种单元芳烃的几何构型，计算苯环上C原子电荷分布。 讨论了9种取代基的定位效应，以苯环取代基以外环上C原子总净电荷QRΣC(2~6)表示单取代苯的硝化反应活性与硝化强度φ之间的关系。 实验结果表明，烷基苯、卤苯、硝基苯的硝化反应活性与其混酸硝化转化率达最大时的混酸硝化强度φ呈良好的线性关系。

Nitration of Single-substituted Benzenes

With toluene, ethylbenzene, cumene, tert butyl benzene and fluorobenzene as the substrates, the nitration strength(φ) data were recorded when the highest yields of nitration products were obtained in mixed acids. By the method of Density Functional Theory, the groups geometries of nine kinds of aromatic were optimized at the level of B3LYP/6-311G**, and the charge distribution was analyzed. Based on this study, the effects of positioning nine kinds of substituents were investigated, and the relationship between the activity of single-substituted benzene nitration expressed in QRΣC(2~6), and nitrification strength was discussed. Experimental results show that the nitration activity of alkylbenzene, halogen benzene or nitrobenzene has a good linear relationship with the nitration strength(φ) when the highest yield of nitration product is obtained in mixed acid.