5-Bromo-1,2,3-trifluorobenzene

1489-53-8

138526-69-9

3,4,5-trifluorobromobenzene was synthesized as follows: (1) 1 mole of 1,2,3-trifluorobenzene and 3 moles of methylene chloride were added to a 2-liter reaction flask, and the mixed solution was cooled to 8-12°C; (2) 1.0 mole of sodium bromide and 120 g of sodium dihydrogen phosphate were dissolved in water to prepare an aqueous solution, which was cooled to 12°C and then added to the reaction flask of step (1); (3) at 15°C, a 10% sodium hypochlorite solution containing 1.2 moles of sodium hypochlorite was slowly added dropwise to the reaction flask, and the dropwise process lasted for 100 minutes, and then the reaction was continued at the same temperature for 60 minutes; (4) after completion of the reaction, the reaction was static layered, and the organic phase was separated, washed with water to neutrality, and dried with calcium chloride, and then the solvent was removed, and the crude 3,4,5-trifluorobromobenzene was obtained; (5) the crude product was at -25 °C Melt recrystallization was carried out to obtain 200 g of pure 3,4,5-trifluorobromobenzene with a yield of 94.6% and a purity of 99.5%.