Acetyl chloride (11.8 g, 150 mmol) was slowly added dropwise to a stirred mixture of 1,2,4-trichlorobenzene (18.2 g, 100 mmol) and anhydrous aluminum trichloride (33.4 g, 250 mmol) at room temperature. The reaction mixture was then gradually heated to 120-125°C (oil bath heating) and the reaction was maintained at this temperature for 3 hours. Upon completion of the reaction, the resulting viscous mixture was carefully poured into ice water (125 mL) to quench the reaction, followed by extraction of the aqueous phase with dichloromethane (3 x 70 mL). The organic phases were combined, dried with anhydrous magnesium sulfate, filtered and the solvent concentrated under reduced pressure. The residue was purified by distillation under reduced pressure to give a colorless liquid product which solidified to a solid after standing at room temperature. Yield: 15.6 g (82% yield); melting point: 43-45 °C, boiling point: 135 °C/6 mmHg (literature values: melting point 47 °C [29]; 44-46 °C [30]; 45.5-46 °C [31], boiling point 114-116 °C/2 mmHg [31]).
