| 摘要 |
A perfluoropolyether, a composition comprising the perfluoropolyether, a process for producing the perfluoropolyether, and a process for improving the thermostability of grease or lubricant are provided. The perfluoropolyether comprises perfluoroalkyl radical end groups in which the radical has at least 3 carbon atoms per radical and is substantially free of perfluoromethyl and perfluoroethyl end groups. The process for producing the perfluoropolyether can comprise (1) contacting a perfluoro acid halide, a C<SUB>2</SUB>-to C<SUB>4</SUB>-substituted ethyl epoxide, or a C<SUB>3+</SUB> fluoroketone with a metal halide to produce an alkoxide; (2) contacting the alkoxide with either hexafluoropropylene oxide or tetrafluorooxetane to produce a second acid halide; (3) esterifying the second acid halide to an ester; (4) reducing the ester to its corresponding alcohol; (5) converting the alcohol with a base to a salt form; (6) contacting the salt form with a C<SUB>3 </SUB>or higher olefin to produce a fluoropolyether; and (7) fluorinating the fluoropolyether. The process for improving the thermostability of a grease or lubricant comprises combining the grease or lubricant with the composition.
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