ATTEMPTS TO PREPARE FLUOROETHERS WITH EMPHASIS ON THE USE OF LITHIO-PERFLUOROALKANES IN ORGANIC SYNTHESIS.
ROYAL AIRCRAFT ESTABLISHMENT FARNBOROUGH (ENGLAND)
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In the search for new elastomers suitable for use at high temperatures, certain aliphatic polyfluoroethers appear promising candidates for the base polymer. Attempts made to prepare as a model bis-1-1-di-H-heptafluorobutyl ether, by potential polymer forming reactions, were unsuccessful perfluoro-n-propyl-lithium was insufficiently stable to undergo condensation with sym-dichlorodimethyl ether, and O-alkylation of 1-1-di-H-heptafluorobutyl trifluoromethane- sulphonate with sodium 1-1-di-H-heptafluorobutoxide could not be effected. Perfluoro-n-heptyl-lithium and 1-4-dilithio-octafluorobutane were prepared by halogen-metal exchange and characterised by their reactions with acetaldehyde they are much less stable than perfluoro-n-propyl-lithium. The proportion of alkyl-lithium compound used for the exchange had a considerable effect on the stability of the fluoro-organometallic reagent. Perfluoro-n-propyl-, perfluoroisopropyl-, and perfluoro-n-heptyl-lithium could be carboxylated at low temperature. Author
- Polymer Chemistry