Processes for the separation of potassium salts of perfluoroalkanoic acids from aqueous solutions thereof

US4049681A · kind A · utility

Assignee

• Akademie der Wissenchaften der DDR · DE

Inventors

• Peter Dietrich · Berlin, DE
• Gunter Engler · Berlin, DE
• Armin Ferse
• Harald Grimm · Hague, US
• Udo Gross · Berlin, DE
• Klaus Lunkwitz · Dresden, DE
• Dietrich Prescher · Berlin, DE
• Jurgen Schulze · Potsdam, DE
• Astrid Wallbraun · Berlin, DE

Key dates

• Filing date: Dec 18, 1975
• Grant date: Sep 20, 1977
• Expiry date: Dec 18, 1995

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C51/48
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

Processes for the separation of a potassium salt of a perfluoroalkanoic acid having at least 1 and at most 12 carbon atoms per molecule or a mixture of potassium salts of a homologous mixture of the said perfluoroalkanoic acids from an aqueous solution that also contains a substantial proportion of one or more watersoluble salts of inorganic acids which process comprises extracting at room temperature the said aqueous solution with an organic solvent which is at least partially miscible with water and in which potassium salts of the said perfluoroalkanoic acids are soluble, the said organic solvent being selected from the group consisting of alkanols having at least 3 and at most 5 carbon atoms per molecule, ketones having at least 3 and at most 7 carbon atoms per molecule, N,N-dimethylformamide and dimethyl sulfoxide, and subsequently recovering the potassium salt of the perfluoroalkanoic acid or mixture of potassium salts of the homologous mixture of perfluoroalkanoic acids.