Recovery of perfluorinated polyether oils from grease matrices incorporating extraction aids by carbon dioxide extraction

A process for extracting a perfluoropolyether from lubricating grease, comprising:

• (a) contacting a solvent comprising a liquid or supercritical carbon dioxide with the lubricating grease, wherein the lubricating grease comprises a thickener, extraction aid material, and the perfluoropolyether in an extraction zone to form an extraction solution comprising an extracted perfluoropolyether and wherein the extracted perfluoropolyether comprises unfunctionalized perfluoropolyether and optionally functionalized perfluoropolyether, the functionalized perfluoropolyether if present being present in an amount of no more than 10 wt % based on the total amount of perfluoropolyether;
• and
• (b) recovering the extracted perfluoropolyether from the extraction solution;
• wherein the recovered extracted perfluoropolyether comprises no more than about 2 wt % of the thickener;
• wherein the yield of the extracted perfluoropolyether is at least about 75 wt %.