申请人:Central Glass Company, Limited
公开号:US04927962A1
公开(公告)日:1990-05-22
A fluorocarbon carboxylic acid Rf(COOH).sub.m (Rf is C.sub.1 -C.sub.10 perfluoroalkyl group, m is 1 or 2) is prepared by the steps of hydrolyzing Rf(COF).sub.m with water to obtain an acidic solution, neutralizing the acidic solution with aqueous solution of KOH to form Rf(COOK).sub.m, precipitating and separating Rf(COOK).sub.m from the solution and converting Rf(COOK).sub.m into Rf(COOH).sub.m by acid decomposition. The content of free fluorine can extremely be reduced by treating Rf(COOK).sub.m with sulfuric acid and silica. The mother liquor is recycled after removing KF by treatment with a metal hydroxide and replenishing with KOH. In preparing a fluorocarbon sulfonic acid RfSO.sub.3 H (Rf is C.sub.1 -C.sub.3 perfluoroalkyl group) in substantially the same way, RfSO.sub.3 K is formed in aqueous solution of KOH by bringing gaseous RfSO.sub.2 F into contact with the KOH solution under normal pressure, while controlling the feed rate of RfSO.sub.2 F per unit area of gas-liquid contact at a sufficiently low level.
通过以下步骤制备氟碳羧酸Rf(COOH).sub.m(其中Rf是C.sub.1-C.sub.10全氟烷基,m为1或2):用水水解Rf(COF).sub.m以获得酸性溶液,用氢氧化钾水溶液中和酸性溶液以形成Rf(COOK).sub.m,从溶液中沉淀和分离Rf(COOK).sub.m并通过酸分解将其转化为Rf(COOH).sub.m。通过用硫酸和二氧化硅处理Rf(COOK).sub.m可以极大地降低游离氟的含量。通过用金属氢氧化物处理并补充氢氧化钾后,可以去除KF并回收母液。在基本相同的方式下制备氟碳烷基磺酸RfSO.sub.3 H(其中Rf是C.sub.1-C.sub.3全氟烷基),通过使气态RfSO.sub.2 F在常压下与KOH溶液接触,同时控制每单位气液接触面积的RfSO.sub.2 F进料速率足够低,可以在KOH水溶液中形成RfSO.sub.3 K。