Benzoic Acid → Benzoic acid, 3-(chlorosulfonyl)-

Participants

Reaction Conditions

Reaction Steps

122.1 g (1.0 mol) of benzoic acid are introduced into a mixture of 349.5 g (3.0 mol) of chlorosulfonic acid, 20 g of 96% strength sulfuric acid and 1 g of sulfamic acid. The reaction mixture thus obtained is heated to 120° C. in the course of 3 hours and stirred until evolution of gas has ended. The mixture is then cooled to 70° C. and 119.0 g (1.0 mol) of thionyl chloride are added dropwise over the course of 2 hours. After it has been stirred at 80° C. for 30 minutes, the reaction mixture is added dropwise at 10° C. to ice water, and the precipitated crystals are filtered off with suction and washed with ice water. 232.1 g of 3-chlorosulfonylbenzoic acid (water content: 10%), corresponding to 208.9 g (94.7% of theory), calculated as dry material, having a melting point of 129°-131° C. are obtained.

Provenance & Evidence