Synthesis and Dielectric Properties of Trifluoromethanesulfonyl Fluoride: An Alternative Gas to SF₆

Abstract

Sulfur hexafluoride (SF6) gas has been used in large-scale electrical equipment, because of its excellent high-voltage dielectric strength. However, SF6 has been identified as a greenhouse gas, because of its high global warming potential (GWP) and extended lifetime in the atmosphere. Based on theoretical calculations, trifluoromethanesulfonyl fluoride (CF3SO2F) is a relatively eco-friendly gas with a lower GWP than that of SF6, and the electrical performance of CF3SO2F is also superior to that of SF6. A new procedure to synthesize CF3SO2F gas is presented for application in high-voltage insulation. An AC breakdown voltage test involved mixing CF3SO2F with CO2 and N2 to obtain insulation data. The stability of CF3SO2F was shown by self-recoverability tests and decomposition product analysis after breakdown, and the results show no harmful or flammable and explosive byproduct that would have a negative climate impact. These results demonstrate that CF3SO2F gas has great potential as a new insulating gas with great dielectric strength.

SuFEx-enabled, chemoselective synthesis of triflates, triflamides and triflimidates

“…Sterically hindered triflates 8, 12 and 27 were also formed efficiently. Although 19 F NMR monitoring of catechols showed a high degree of ditriflation at the reaction onset, they nevertheless converged to the monotriflates (14 and 16) after longer reaction times, most…”

SuFEx-Enabled, Chemoselective Synthesis of Triflates, Triflamides and Triflimidates

“…With a few experimental adaptations and shorter reaction times, however, it was possible to get the less stable ditriflates 15 and 17 in a fair isolated yield. The triflation of two L-tyrosine derivatives not only offered corresponding products in excellent yields (24 and 25), but also without loss of enantiopurity (25). When it comes to naturally occurring phenols, all afforded the corresponding monotriflates in good to excellent yields (4, 9, 10, 19, 20, 26, 27 and 29).…”

“…[24] This smallest perfluoroalkanesulfonyl fluoride is gaseous above -25 °C, and its atmospheric chemistry is relatively innocuous. [25] The most relevant industrial preparation consists of the electrolytic fluorination of methanesulfonic acid or methanesulfonyl fluoride, and the resulting gas serves as the precursor to all other [CF3SO2]-containing bulk chemicals such as TfOH or Tf2O. [26] Other authors have prepared triflyl fluoride on a semibulk scale, by reacting CF3SO2Cl [27,25] or Tf2O [28] with a fluoride source.…”

“…[25] The most relevant industrial preparation consists of the electrolytic fluorination of methanesulfonic acid or methanesulfonyl fluoride, and the resulting gas serves as the precursor to all other [CF3SO2]-containing bulk chemicals such as TfOH or Tf2O. [26] Other authors have prepared triflyl fluoride on a semibulk scale, by reacting CF3SO2Cl [27,25] or Tf2O [28] with a fluoride source. [29] Recently, Pees and coworkers have developed CF3SO2 18 F as a carrier gas for nucleophilic [ 18 F]-fluoride, evolving it from PhNTf2 as a precursor.…”

“…[34] Even though the gas-free methods required a shorter reaction time, the corresponding triflates were almost universally obtained in lower yield than with CF3SO2F. Not only did the literature methods require more careful temperature control or moisture exclusion, also the chemoselectivity was usually inferior when the phenol starting materials contained indoles (19), aliphatic amines (24 and 28), carboxylic acids (25) or aliphatic alcohols (27). Moreover, amine 28 did not show any trace of sulfonamide formation, even with 2.5 equivalents of gas (see SI section 5.1).…”