The perfluoroalkylsulfonate monomer, N,N-diisopropylethylammonium 2,2-bis(p-hydroxyphenyl)pentafluoropropanesulfonate (H PPS), was synthesized in three steps. Using triethyl phosphite, hexafluoroacetone was first converted to ethyl pentafluoroisopropenyl ether. Reaction of the ether with sulfur trioxide produced 2-ketopentafluoropropanesulfonic acid. The acid was condensed with 2 equiv of phenol, and the product was isolated as the N,N-diisopropylethylammonium salt. The structure of the final product was confirmed by X-ray crystallography. Poly(arylene ether sulfone)s (PAES) were prepared by homopolymerization of HPPS with bis(4-fluorophenyl) sulfone (FPS) and copolymerization of varying molar ratios of HPPS/biphenol (BP) with FPS. Copolymer number-average molecular weights were in the range 27 000-34 000 g/mol (GPC). Copolymer compositions ranged from 20 to 61 mol % HPPS (HPPS/BP molar ratio 0.25-1.56) as determined by F-19 NMR spectroscopy. Ion exchange capacity of the copolymers (by titration) ranged from 0.36 to 1.25 mequiv/g. Equilibrium water uptake of the copolymers at 80 degrees C and 90% relative humidity increased from 7.2 to 14.3 mol H2O/mol H+, and proton conductivity increased from 1.6 to 23 mS/cm, as the HPPS/PB ratio increased from 0.25 to 1.56.
Novel .beta.-carbonylpolyfluoroalkyl sulfonate esters, e.g., ##STR1## are prepared by reacting SO.sub.3 with the corresponding acyclic fluorovinyl esters, e.g., CF.sub.3 CF.dbd.CFOCH.sub.3, at a temperature of about -40.degree. to 110.degree. C. These esters are useful as very active cationic initiators, e.g., for the polymerization of tetrahydrofuran.
2-Ketopentafluoropropanesulfonic acid and related acids
申请人:E. I. Du Pont de Nemours and Company
公开号:US04160780A1
公开(公告)日:1979-07-10
2-Ketopentafluoropropanesulfonic acid is obtained as a product of the reaction of sulfur trioxide and ethyl pentafluoroisopropenyl ether or by transesterification from corresponding esters. Similar sulfonic acids may be obtained by the latter process. The new compounds are useful as monomers for producing polymers, particularly moldable, dyeable, fluoropolymers, and as cationic initiators, e.g., for tetrahydrofuran polymerization.