- SYNTHESIS OF FLUORINATED DIFUNCTIONAL MONOMERS
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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.
- Takakura, T.,Yamabe, M.,Kato, M.
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