PURIFICATION OF TRIFLUOROMETHANE SULFONIC ACID ANHYDRIDE

PROBLEM TO BE SOLVED: To provide a method for purifying trifluoromethane sulfonic acid anhydride useful as a raw material for producing medicines, agrochemicals, etc., capable of easily purifying the trifluoromethane sulfonic acid anhydride in a high purity and in a high yield by adding phosphoric acid. SOLUTION: This method for purifying trifluoromethane sulfonic acid anhydride comprises adding (C) phosphoric acid to (B) the trifluoromethane sulfonic acid anhydride containing (A) phosphorus oxychloride and then subjecting the mixture to a distillation treatment. The component B containing the component A is preferably obtained by either of reactions expressed by formulas I and II. The component C is preferably added in an amount of >=0.1 mole per mole of the component A at a temperature of