The general procedure for the synthesis of 2,6-dibromo-4-(trifluoromethoxy)aniline from p-trifluoromethoxyaniline was as follows: first, 156 g of the crystallized mother liquor containing sodium sulfate was filtered into a 250 mL four-necked flask and the stirring apparatus was started. Subsequently, 17.5 g (0.175 mol) of the reagent was slowly added dropwise, followed by 36.5 g of sodium bromide (0.354 mol) and 30 g (99% purity, 0.168 mol) of 4-trifluoromethoxyaniline. The temperature of the reaction system was adjusted to above 30 °C and the dropwise addition of 38 g of 35% hydrogen peroxide solution was started. During the dropwise addition, if the temperature increased to 50 °C, the reaction temperature was controlled between 50 and 55 °C by adjusting the dropwise acceleration of the coolant. After the dropwise addition was completed, the reaction temperature was maintained to drop and the reaction was continued to be held for 3 hours. Upon completion of the reaction, the system was cooled to about 30°C and the filtration operation was carried out. The resulting filter cake was dried to obtain 55.8 g of white crystals of 2,6-dibromo-4-trifluoromethoxyaniline, which was analyzed by high performance liquid chromatography (HPLC) with a purity of 99.6% and a yield of 99.2%.
