Perfluorophenyl Ether and Related Polymers

The syntheses of perfluorophenyl ether and poly (perfluorophenylene ethers) are described. These materials were prepared by the reaction between potassium pentafluorophenoxide and hexafluorobenzene in different solvents with varying conditions of temperature and pressure. In dimethylformamide or tetrahydrofuran, potassium pentafluorophenoxide shows little tendency to react with hexafluorobenzene. In methanol, only exchange products such as pentafluoroanisole were observed. No polymers were obtained in these solvents. In water, the reactivity of pentafluorophenoxide salts was increased greatly, for reaction occurs readily with or without the presence of hexafluorobenzene. The reactions in aqueous systems are complex and give rise to a variety of products. From these reactions the following compounds were isolated and identified: perfluorophenyl ether, bis(pentafluorophenoxy)tetrafluorobenzene, 2,4,5,6-tetrafluororesorcinol, pentafluorophenoxytetrafluorophenol, and various polyperfluorophenylene ethers of varying chain lengths. Identification of the smaller molecules was made by chemical, mass spectrometer, infrared, and nuclear magnetic resonance analyses. Poly(perfluorophenylene ethers) were prepared having molecular weights of 1700, 4300, 6500, and 12,500. A crosslinked polyether of this type was also synthesized, which had rubbery characteristics above 90 °C.