A 2 L reactor was charged with 183.7 g (38% purity, 0.38 mole) of sodium 2-hydroxy-1,1-difluoroethanesulfonic acid, 300 mL of water, 450 mL of chloroform and an aqueous solution of triphenylsulfonium chloride [142.8 g (0.49 mole/1.25 equivalents) of triphenylsulfonium chloride and 150 mL of water], followed by stirring at room temperature for 1 hour. A reaction solution was analyzed by using nuclear magnetic resonance (NMR), by which there was found almost half the raw material sodium 2-hydroxy-1,1-difluoroethanesulfonic acid remaining. Accordingly, the reactor was further charged with the aqueous solution of triphenylsulfonium chloride [142.8 g (0.49 mole/1.25 equivalents) of triphenylsulfonium chloride and 150 mL of water], followed by stirring at room temperature for 0.5 hour (triphenylsulfonium chloride was used in an amount of 285.7 g (0.96 mole/2.5 equivalents) in total and the reaction time was 1.5 hours in total). The reaction solution was analyzed by using nuclear magnetic resonance (NMR), by which the raw material was detected being consumed. Thereafter, the reaction solution was separated. The obtained water layer was extracted with 100 mL of chloroform three times while distilling a solvent out of the obtained organic layer, thereby obtaining 328.2 g of the target triphenylsulfonium 2-hydroxy-1,1-difluoroethanesulfonate. In this case, the purity was 48% and the yield was 97%.
