The general procedure for the synthesis of 2,3,5-trifluoroaniline from aniline was as follows: 9.3 g (0.1 mol) of aniline was dissolved in 50 mL of glacial acetic acid, cooled to 10 °C, and then 8.2 g (0.12 mol) of sodium nitrite was slowly added. Subsequently, a solution prepared from 33 g (0.3 mol) sodium borohydride dissolved in 50 mL of water was added slowly and dropwise at the same temperature. After completion of the reaction, the product was separated by filtration. The filtrate was extracted by adding 100 mL of ethyl acetate to the filtrate and this operation was repeated three times. The organic phases were combined and washed sequentially with 10 mL of aqueous sodium fluoroborate and 50 mL of pure water. Finally, the organic phase was evaporated to dryness to give 9 g of 2,3,5-trifluoroaniline.
