Perfluoroalkanesulphonic Acids and Related Compounds

Trifluoromethanesulphonic acid, now usually referred to as triffic add, and its derivatives (trifkites, triflamides, etc.) are fast becoming commonplace reagents in 

Publications are available that deal with (i) the crystal structtire of trifluoromethanesulphonic acid monohydrate (ii) protonation of CFa-COsH and CH,Cl8- -C02H (x = 0—3) by CFs-SOsH (i.r. studies)(iii) S- versus 

Verastegui, G. Durand, and B. Tremillon, J. Electroanalyt. Chem. Interfacial Electrochem., 1974, 54, 269 Chem. Abs., 1974, 81, 98 610u) (electrochemical charactistics of CF,-SO,H as a solvent for oxidation processes) A. A. Adams and H. J. Barger, J. Electrochem. Soc., 1974, 121,987 Chem. Abs, 1974,81,124 116j) (CFj SOaH.HjO as an electrolyte for hydrocarbon-air fuel cells). 

CH2)aO(ca.5%)] and RrCHa OTf + EtONa-EtOH (at ca. 5 C for 10 min.) EtaO (ca.40 %) and EtO CHaRp [Rp = CFs (23 %) or n-CsFv (17 %)] (these unsym-metrical ethers can be obtained in ea. 70% yield from RpCHa-ONa + EtBr ). The reaction RpCHa OTf + RpCHa-ONa-RpCHa OH (Rp = n-CsF ) at 80—100 °C gives a complex mixture containing some (RpCH2)aO (ca. 35 % yield). 

Reagents i, MesSiCl-EtoN-DMF ii, MeLi-MeO-CH2-CH2-OMe then (CF2-803)20 iii, Bu OK-oyolohexcne (or other olefin) at 0 °C (usually). 

Perfluoroalkanesulphonic Acids and Related Compounds. Continued industrial interest in this area of fluorocarbon chemistry has ensured a steady flow of patent literature relevant to this Report, some of which has been included in a list at the end of this chapter (p. 287). 

Interaction of xenon difluoride with a solution of trifluoromethane-sulphonic acid in hydrogen fluoride at 0 °C yields a solid product possessing 

Reagents i, CHj C 0-ether ii, NHj-ether iii, PjOj, heat in vacuo iv, these Knoe-venagel reactions involved the appropriate aldehyde or ketone, piperidine as catalyst, and boiling benzene as the reaction medium v, CHiiCH COjMe, U.V. light [CFaSCHu-CHClCOjMe and CHjClCH(COijMe)CH, CH(S-CF,) CO,Me are also formed] vi, EtjN-ether vii, room temperature (slow) viii, boiling HCl(aq) ix, SOCii, A x, CHjiCH-CO-NHj-MeCN. 

RfSOsH (Rp = C7FU, C9F1, CiiFj , or C1SF27)] in water and in 6M-HjSOa (viii) the conversion of methyl polyfluoroalkyl sulphides obtained via the routes described above (p. 276) into the correspondiitg polyfluoro- 

CFa-CHg SOjF, CFj CH SO,F, MeCF, O SOjF, MeCFj, and SO F ) and (xii) Michael addition of arylsulphonylacetonitriles to 1,2-dicbloro-1,2,2-trifluoroethyl vinyl sulphone [CHjrCH-SOj CFCl-CFjCl (from  

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Perfluoroalkanesulphonic Acids and Related Compounds. In addition to work on the electrochemical fluorination of sulphones noted earlier (see above), application of this technique to sulpholene and 3-methylsulpholene, respectively, has been shown to yield perfluorobutane-l-sulphonyl fluoride and a mixture of the isomers CFs-(CF2)4S02F, (CF3)2CF-(CF2)2 S02F, and CFs CF2 CF(CF,)-CFj S02F. The preparation of perfluoropropane-2-sulphonyl fluoride via the carbanion route, using perfluoropropene. 

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