Sulfuric Acid → 2,4,5-Trifluorobenzenesulfinic acid

Participants

Reaction Steps

2,4,5-Trifluoro-benzenesulfonyl chloride ([220227-21-4], 2.5 g) was added portionwise onto a solution of sodium sulfite (10.3 g) in 50 mL of water. The reaction mixture was kept under basic conditions by the addition of the proper amount of 20% NaOH and was stirred at room temperature for 1 hour. Methanol was added to the reaction mixture, and the reaction mixture was stirred at room temperature for another hour. After such time, the reaction mixture was cooled down with an ice bath and was then acidified by the addition of 20% H2SO4 solution until reaching pH 2. The aqueous solution was then extracted several times with diethyl ether and ethyl acetate. The aqueous solution was further extracted with ethyl acetate using a Kutscher-Steudel apparatus (continuous extraction). The combined organic phases were dried (sodium sulfate) an concentrated in vacuo to yield the title compound as a white solid (2.1 g).

Provenance & Evidence