The invention concerns a method for preparing sulphonate salts, alkaline or alkaline-earth, corresponding to anion of general formula (I):(R--CF.sub.2 --SO.sub.3.sup.-).sub.n, through alkaline hydrolysis of sulphonyl chlorides corresponding to formula (II). The invention is characterized in that it comprises at least a step which consists in alkaline hydrolysis of sulphonyl chloride carried out in the presence of a phase-transfer agent.

A invenção concerne um método para preparar os sais do sulphonate, alcalino ou alkaline-earth, correspondendo ao anion da fórmula geral (I):(R -- CF.sub.2 -- SO.sub.3.sup.-).sub.n, com o hydrolysis alcalino dos cloretos do sulphonyl que correspondem à fórmula (ii). A invenção é caracterizada que compreende ao menos uma etapa que consista no hydrolysis alcalino do cloreto do sulphonyl realizado na presença do fase-transfira o agente.