Study On Selective Synthesis And Oxidative Coupling Of Nitro-o-xylene

An improved process for selective synthesis of4-and3-nitro-o-xylene respectively using fuming nitric acid and sulfuric-nitric acids over graphite oxides support catalyst was developed. And the nitro-o-xylene precursor could be further converted polynitrobibenzyls compounds by the oxidative coupling reaction with polynitrobenzenes using molecular bromine in the presence of potassium terf-butoxide alcohol solution.Nitro-o-xylenes in80.8%yield were selectively prepared with95%nitric acid up to a ratio of0.52of3-nitro to4-nitro isomers in90.3of substrate conversion accompanied by2-methyl-4-nitrobenzoic acid formation. g raphite oxides promoted the reaction yield to83.5%in the isomer ratio0.50of3-nitro to4-nitro isomers. Moreover sulfuric-nitric acids could nitrate o-xylene effectively. The95.4%yield of mononitrocompounds in a ratio of1.18of3-nitro to4-nitro isomer was obtained. Graphite oxides slightly affected yield and selectivity.Oxidative couplings of nitro-o-xylene isomers using molecular bromine in the presence of potassium tert-butoxide catalyst were conducted to form dinitrobibenzyls compounds. The81.2%yield of2,2’-dimethyl-4,4’-dinitrobibenzyl and55.9%yield of2,2’-dimethyl-6,6’-dinitrobibenzyl were obtained respectively. Under the same conditions, the reaction behaviors of nitro-o-xylene with3,4,5-trinitro-o-xylene,3,4,6-trinitro-o-xylene,2,4,6-trinitro-m-xylene,2,3,5-trinitro-p-xylene and2,4,6-mesitylene were further discussed to form polynitrobibenzyls.