Abstract:

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.

Key words: Aromatics, mixed acid nitration, quantum chemistry calculation, position effection