Regioselective Synthesis of Mononitrochlorobenzene (II)Nitration with Nitrogen dioxide

Ozone mediated nitration of chlorobenzene with nitrogen dioxide over solid acid catalysts is expected to be a green process. The reaction was carried out at ca . 0 ℃. It was found that the solid acid catalysts of SO 2- 4/TiO 2 and SO 2- 4/ZrO 2 and a series of SO 2- 4/TiO 2 ZrO 2 catalysts exhibited a fairly good activity for the nitration reaction, whereas SO 2- 4/TiO 2 ZrO 2(atomic ratio 1∶1) gives yield of 62 4% and SO 2- 4/TiO 2 ZrO 2(molar ratio 3∶1) shows a good para selectivity in CH 2Cl 2 solvent. The ortho para isomer ratios( ortho/para ) of the nitration products were varied in range from 1 11 to 0 36. This phenomenon is interpreted in terms of acid amount and acid strength of solid acid catalysts.