2-Chloro-2',4'-difluoroacetophenone

372-18-9

79-04-9

51336-94-8

In a 250 mL four-necked flask equipped with a thermometer, a constant pressure dropping funnel, and a reflux condenser (with a drying tube), 1,3-difluorobenzene (0.1 mol, 14.7 g) and anhydrous aluminum trichloride (0.17 mol, 22.7 g) were added. The mixture was stirred at 30-35°C for 0.5 hours. Subsequently, chloroacetyl chloride (0.12 mol, 13.56 g) was slowly added dropwise to maintain the reaction temperature. After the dropwise addition was completed, the temperature was raised to 50-55 °C and the reaction was continued with stirring until no hydrogen chloride gas escaped, a reaction time of about 5 hours. The reaction mixture was cooled to below 5°C in an ice-water bath, and acid hydrolysis was carried out by slowly dropping 3 mol/L hydrochloric acid (20 mL), controlling the rate of dropwise acceleration to keep the temperature of the mixture low. The acid-hydrolyzed mixture was poured into a beaker and distilled water was added to precipitate the solid. After filtration and drying under reduced pressure, 16.9 g of light yellow powdery solid was obtained in 89.3% yield. Finally, the light yellow powdery solid was recrystallized with hexane to give bright yellow crystalline 2'-chloro-2,4-difluoroacetophenone.