PROCESS FOR PRODUCING PERFLUOROBUTANESULFONIC ACID SALT

摘要

A process for producing a perfluorobutanesulfonic acid salt (PFBS salt) is provided. By the process, the yield is improved and PFOS salt content is reduced. Electrochemical fluorination is conducted in a reaction solution comprising anhydrous hydrogen fluoride to generate perfluorobutanesulfonyl fluoride, and the fluoride its hydrolyzed to produce a perfluorobutanesulfonic acid salt. The process for producing a perfluorobutanesulfonic acid salt includes: a step in which liquid phase components generated in the electrochemical fluorination cell are withdrawn and a first a perfluorobutanesulfonic acid salt fraction is prepared therefrom; and a step in which gaseous phase components discharged from the electrochemical fluorination cell are collected and a second perfluorobutanesulfonic acid salt fraction is prepared therefrom. The reaction solution in the electrochemical fluorination cell is regulated so as to have a perfluorooctanesulfonyl fluoride content of 500 ppm or lower by withdrawing the liquid phase components from the electrochemical fluorination cell.