SYNTHESIS OF FLUORINATED DIFUNCTIONAL MONOMERS

Article abstract of DOI:10.1016/S0022-1139(00)81542-0

In order to obtain fluorinated difunctional monomers for fluoropolyurethanes, we synthesized novel fluorinated aliphatic diisocyanates (OCNCH2(CF2)nCH2NCO) from corresponding diols (HOCH2CH2(CF2)nCH2CH2OH).Oxidation of the diols with chromium trioxide-sulfuric acid gave α,α,ω,ω-tetrahydroperfluoroalkylene dicarboxylic acids in high yields.Then treating the acids with phosphorus pentachloride afforded corresponding dicarboxyl chlorides, which are easily converted to dicarboxyl azides with hydrazoic acid-pyridine complex.Finally, on Curtius rearrangement of the azides, the end products, α,α,ω,ω-tetrahydroperfluoroalkylene diisocyanates were obtained in 53percent (n=4) and 19percent (n=6) yields from the starting diols.