Sodium Hydroxide → 3-Chloro-4-methylbenzenesulfinic acid

Participants

Reaction Steps

1800 ml of water and 420 g (3.3 mol) of sodium sulfite are charged into a stirred apparatus fitted with 2 dropping funnels and a pH electrode and heated to from 50° to 55° C. Over a period of about 2 hours, 677 g (3 mol) of 3-chloro-4-methylbenzenesulfonyl chloride and at the same time 690 g of NaOH, 35% strength, are allowed to run in in such a way that a pH from 8 to 10 is always maintained. The temperature may be allowed to rise to 65° C. The reaction is complete when the pH from 8 to 10 remains constant. The 3-chloro-4-methylbenzenesulfinic acid (Na salt) produced is dissolved at 65° C. and partially crystallizes out from about 55° C.

Provenance & Evidence