FIELD: chemical industry. SUBSTANCE: claimed process comprises contacting fluorinated sulphonyl fluoride with water in the presence of main agent, separating from reaction medium mixture comprising corresponding fluorinated sulphonic acid in the form of main agent salt and hydrofluoric acid in the form of main agent salt and separating the desired product. The claimed process makes it possible to increase conversion for shorter reaction time. The claimed process does not use high temperatures during main hydrolysis operation. EFFECT: more efficient preparation process. 9 cl
