PROCESS FOR PRODUCING PERFLUOROBUTANESULFONIC ACID SALT

摘要

A process for producing a perfluorobutanesulfonic acid salt (PFBS salt) is provided with which it is possible to attain an improvement in yield and a reduction in PFOS salt content. Electrolytic fluorination is conducted in an electrolytic solution comprising anhydrous hydrogen fluoride to yield perfluorobutanesulfonyl fluoride, and the fluoride is hydrolyzed to yield a perfluorobutanesulfonic acid salt. The process for producing a perfluorobutanesulfonic acid salt includes: a step in which liquid-phase components generated in the reaction tank are withdrawn and a first perfluorobutanesulfonic acid salt fraction is prepared therefrom; and a step in which gas-phase components discharged from the reaction tank are collected and a second perfluorobutanesulfonic acid salt fraction is prepared therefrom. The electrolytic solution in the reaction tank is regulated so as to have a perfluorooctanesulfonyl fluoride content of 500 ppm or lower by withdrawing the liquid-phase components from the reaction tank.