Sodium Hydroxide → 2-Bromo-5-methylbenzenesulfinic acid

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Reaction Conditions

Reaction Steps

37.6 g of sodium sulfite are dissolved in 500 ml of water and heated to 70° C. 62 g of 2-bromo-5-methylbenzenesulfonyl chloride are added in portions at this temperature. A 10 N aqueous NaOH solution is simultaneously added dropwise here so that the pH of the solution is kept between pH=9 and pH=10. The mixture is stirred at 70° C. for 1.5 hours, and the solution is filtered off and subsequently adjusted to pH=0 in an ice bath using a saturated aqeuous HCl solution. The mixture is stirred for 30 minutes, then the product is filtered off, subsequently washed with a little water and dried. 49.6 g of white crystals are obtained, mp 120-122° C. MS (ES): 236 (M+H)+

Provenance & Evidence