A Substituted Benzene Nitration Study

The recent progress of region selectivity research for aromatic nitration was one of hottest topic. The effects of urea on the region selectivity and the conversion of nitration reaction for toluene as substrates were investigated in this paper.Industrial nitrifying outcomes of toluene include three isomers: o-nitrotoluene(60%) , m-nitrotoluene(4%) , p-nitrotoluene(36%). Market demand of nitrotoluene has apparently rised these years. The research on nitration of toluene is practical. The results showed that in the present of carbamide yield of p-nitrotoluene increased by 4.5%. The influences of experimental conditions such as the urea, strength of the nitro-sulfuric and reaction temperature were also investigated. It showed that the p-nitrobenzene increased 4.5% when urea was added.Nitration of mono-substituted arene are mostly nitrified in mixed acids. So the study of the relationship between nitrifying activities of mono-substituted arene and nitrification intensity of mixed acid is of doctrinal importance and practical application value. A series of mono-substituted benzenes, such as toluene, ethylbenzene, isopropyl benzene, tert-butyl benzene and fluobenzene were investigated as substrates. The nitrification intensity of mixed-acid was obtained under maximum conversion. Geometry configuration of nine mono-substituted benzenes were optimized and electric charge distribution of nine mono-substituted benzenes by means of density functional theory(DFT) method at B3LYP/6-311G** level. For further, the orientation effect of nine disparate substituents were described in the paper. The relationship between nitrifying reactivity and nitrification intensity were inquired using Q~R∑C(1～5) as denotation. The experiment showed that linear relationship existed under maximum conversion using alkylbenzene, benzene halide and nitrobenzene as nitration reactant.