1671-18-7

3185-99-7

1671-18-7

100 g of 4-methylsulfonyltoluene and 156 g of 98% sulfuric acid (concentration 18.4 mol/L) were added to a 500 mL four-necked flask with stirring and controlled reaction temperature. The reaction progress was monitored by gas chromatography by passing chlorine into the mixed solution at 52°C at a chlorine flow rate of 18 m3/h. The reaction was carried out by gas chromatography. When the impurity content in the reaction system decreased to about 1%, the chlorine passage was stopped and the reaction was considered complete. Upon completion of the reaction, the reaction solution was hydrolyzed, cooled to room temperature and filtered. The resulting solid was washed and refined until the content of 2-chloro-4-methylsulfonyltoluene was greater than 98%. Finally, drying gave 117 g of 2-chloro-4-methylsulfonyltoluene in a final molar yield of 95.2%.