Elemental Fluorine Based Syntheses of Pentafluoro Phenly and other Aromatic Perfluoropolyether Polymers

Since we successfully obtained a fused perfluoro benzofuran from perfluoro dicyclohexyl ether, reductive defluorination of the perfluorinated ethers containing three perfluoro cyclohexyl groups would be interesting. The three isomers of o-, m-, and p-perfluoro dicyclohexanoxyl cyclohexane were prepared by liquid-phase direct fluorination of o-, m-, and p-diphenoxyl benzene. After several runs of liquid-phase direct fluorination, enough amount of o-perfluoro dicyclohexanoxyl cyclohexane was collected to carry out the following reductive defluorination. The reductive defluorination was carried out from -70 to 70 degree for 2 days, but the ortho-ether, however, kept unreacted. One of the reasons for that is perhaps steric hindrance. Reductive defluorination of the meta- and para- ethers are under investigation.