(1) To a glass reactor equipped with a reflux condenser, sample inlet, internal cooler, stirring device and solvent was distilled off with an opening and closing cock was charged with 60weight % of hydrogen peroxide solution 295 g (5.20 mol) prepared and 154 g (1.00 mol) of bis(2-hydroxyethyl)disulfide was uniformly added from the sample inlet over 150 minutes and the liquid was stirred. During this time, the temperature of reaction liquid was held at 45 °C by flowing 19 °C cooling water at the flow rate of 140mL/minutes into the condenser. After completion of the addition, the reaction solution temperature was maintained at 50 °C for 2 hours and heated under reflux for 4 hours.
During heating under reflux, the nitrogen gas was blown and the portion of steam was evaporated from the reaction system. 55 weight% aqueous solution of isethionic acid was obtained as a product. Purity of the generated isethionic acid was 244g (1.94 mol) and the yield was 97%. (2) Similarly, there is another synthesis route as shown in scheme 3. The product was obtained in the same manner as above route (1), instead of bis(2-hydroxyethyl)disulfide 154 g (1.00 mol), diethyl disulfide 122 g(1.00 mol) was added, the temperature was maintained at 45 °C by flowing 19 °C cooling water at the flow rate of 140mL/minute into the condenser and the temperature was maintained at 75 °C for 2 hours. 52 weight% aqueous solution of ethanesulfonic acid was obtained as a product. The purity of the generated ethanesulfonic acid was 213 g (1.94 mol) and the yield was 97%.
