Selective Nitration Of Aromatics

The recent progress of region selectivity research for aromatic nitration was one of hottest topic. The effects of surfactants on the region selectivity and the conversion of nitration reaction for toluene and m-xylene as substrates were investigated in this paper.The effects of surfactants on the ratio of m-nitrotoluene were explored by studying the nitration of toluene using nitro-sulfuric acid. The experimental results showed that the content of m-nitrotoluene increases 1.1% with a decrease in o-nitrotoluene 1.3% in the presence of sodium lauryl sulfate. The nitration of toluene using polyethlene glycol (M=600) gived similar result, i. e. once the content of m-nitrotoluene increasd 1.0%, the p-nitrotoluene decreased 2.2%, achieving the proportion of m-nitrotoluene from 3.2% to 5.3% controllability.Furthermore, using the same nitration method, the effects the types and using amount of the surfactants, strength of nitro-sulfuric acid and reaction temperature on the nitration of m-xylene were also investigated. The experimental results showed that surfactants did improve the selectivity and the conversion and under the optimum reaction conditions, high ratio (92.2:7.8) of 2,4-dimethylnitrobenzene to 2,6-dimethylnitrobenzene should be obtained with 100% conversion.