AN IMPROVED PROCESS FOR SYNTHESIS OF POTASSIUM PERFLUOROALKANE SULFONATE

摘要

An improved process for synthesis of potassium perfluoroalkane sulfonate of general formula CnF2n+1 SO3K where n is an integer from 1 to 3, the process comprising subjecting alkanesulfonyl chloride to halogen exchange reaction with aqueous KF followed by electrochemical fluorination to obtain product gas containing perfluoroalkanesulfonyl fluoride; absorbing the product gas in aqueous solution of potassium hydroxide to obtain scrubbed mixture; distilling the scrubbed mixture azeotropically using toluene as a solvent to remove water, to obtain a slurry; mixing acetone to the slurry followed by filtration; separating solid KF which can be recycled again; and distilling the filtrate to separate acetone, toluene and potassiumperfluoroalkane sulfonate. The present process is economical as it results in the product containing less amount of impurities such as chloride, fluoride and sulfate ions and the potassium fluoride obtained as a byproduct can be recycled.