Method for recovering fluorinated emulsifiers
Assignee3M Innovative Properties Company
InventorsStephan Führer, Klaus Hintzer, Gernot Löhr, Werner Schwertfeger
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Abstract
Fluorinated emulsifiers, in particular, perfluorooctanoic acid are bound to anionic exchange resins for the purification of aqueous effluent from the production of fluoropolymers. Said emulsifiers may be quantitatively eluted from the exchanger with a water-miscible organic solvent, containing a small amount of ammonia. It is of advantage to distil off the ammonia containing solvent, recycle the emulsifier to a further polymerization and recycle the ammoniacal solvent for elution. Addition of alkalis improves the elution efficiency.
Claims6
Method for recovering fluorinated emulsifiers from weakly to moderately basic anion exchange resins with (by using) at least one ammonia-containing and water-miscible organic solvent that has a boiling point below 150° C.
Dependencies are inferred from the claim text.