2-Chlorobenzoic Acid → Benzoic acid, 2-chloro-5-(chlorosulfonyl)-

Participants

Reaction Conditions

Reaction Steps

A mixture of o-chlorobenzoic acid (2.0 kg.) and chlorosulfonic acid (10.5 kg.) is heated at 90°-100° C. for 5 hours. The reaction mixture is cooled to 25° C. and then slowly poured into a 10 liter mixture of ice and water. The addition requires about 1 hour, and the temperature is maintained below 10° C. during this period by the addition of more ice. The final volume of slurry after the quench is about 40 liters. The solid material is collected and thoroughly washed on the funnel with fresh water. The crude wet cake is dissolved in 16 liters of diethyl ether. The ether layer is washed once with 2 liters of saturated aqueous sodium chloride solution and then dried over anhydrous magnesium sulfate. The filtered ether solution is concentrated in vacuo with the continual addition of hexane. The resulting hexane slurry is concentrated to a final volume of approximately 8 liters and filtered. The crystalline cake is washed with hexane and dried in the atmosphere to give 2.5 kg. of product (76.8% of theory), m.p. 149°-151° C.

Provenance & Evidence