Regioselective Nitration of Inactive 4,4-Dibromobiphenyl with Nitrogen Dioxide and Molecular Oxygen over Zeolites: An Efficient Preparation of 4,4'-Dibromo-2-nitrobiphenyl

摘要

In the presence of zeolites, 4,4'-dibromobiphenyl could be region-selectively nitrated by the action of nitrogen dioxide and molecular oxygen. The ratio of 4,4'-dibromo-2-nitrobiphenyl to 4,4'-dibromo-3-nitrobiphenyl could reach 14 in a high yield of 90%. Zeolites could be easily regenerated by heating and reused four times to give the results similar to those obtained with fresh catalyst. Compared with the classic nitration method, no nitric acid and sulfuric acid were used, which suggested that the method was an environmentally economic process.