At a temperature of 20°C to 40°C, 23.6 g (0.3 mol) acetyl chloride was added to a mixture containing 29.7 g (0.2 mol) 1-chloro-3,4-difluorobenzene and 40.0 g (0.3 mol) aluminum chloride, and the mixture was then stirred at 120°C for 2 hours. While still very hot, the mixture was poured onto 250 g of ice, and the separated oil was extracted with chloroethane.
The extract was neutralized and washed with water, and the solvent was distilled off under reduced pressure to obtain 31.2 g (yield: 82%) of 2'-chloro-4',5'-difluoroacetophenone, boiling point: 65℃-67℃/4-5 mmHg.
