Triflidic acid

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Triflidic acid
Triflidic acid
Names
IUPAC name
Tris[(trifluoromethyl)sulfonyl]methane
Other names
Triflidic acid, tris(triflyl)methane
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.258.613 Edit this at Wikidata
  • InChI=1S/C4HF9O6S3/c5-2(6,7)20(14,15)1(21(16,17)3(8,9)10)22(18,19)4(11,12)13/h1H
    Key: MYIAPBDBTMDUDP-UHFFFAOYSA-N
  • [H]C(S(=O)(C(F)(F)F)=O)(S(=O)(C(F)(F)F)=O)S(=O)(C(F)(F)F)=O
Properties
C4F9S3O6H
Molar mass 412.23 g/mol
Appearance Colorless solid
Melting point 69.2 °C (156.6 °F; 342.3 K)
Miscible
Acidity (pKa) –18.6 (aqueous, est.) [1]
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
Corrosive, eye irritant
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Triflidic acid (IUPAC name: tris[(trifluoromethyl)sulfonyl]methane, abbreviated formula: Tf3CH) is an organic superacid. It is one of the strongest known carbon acids and is among the strongest Brønsted acids in general, with an acidity exceeded only by the carborane acids. Notably, triflidic acid is estimated to have an acidity 104 times that of triflic acid (pKaaq ~ –14), as measured by its acid dissociation constant. It was first prepared in 1987 by Seppelt and Lutz by the following route:[2]

(1) Tf2CH2 + 2CH3MgBr → Tf2C(MgBr)2 + 2CH4

(2) Tf2C(MgBr)2 + TfF → Tf3C(MgBr) + MgBrF

(3) Tf3C(MgBr) + H2SO4 → Tf3CH + MgBrHSO4

In its anionic form, the lanthanide salts of triflidic acid ("triflides") have been shown to be more efficient Lewis acids than the corresponding triflates.[3][4] The triflide anion has also been employed as the anionic component of ionic liquids.[5]

References

  1. ^ Barrett, A. G. M.; Braddock, D. C.; Raju, G. S. "Tris[(trifluoromethyl)sulfonyl]methane and Related Salts" Encyclopedia of Reagents for Organic Synthesis". doi:10.1002/047084289X.rn00441
  2. ^ Turowsky, Lutz; Seppelt, Konrad (1988-06-01). "Tris[(trifluoromethyl)sulfonyl]methane, HC(SO2CF3)3". Inorganic Chemistry. 27 (12): 2135–2137. doi:10.1021/ic00285a025. ISSN 0020-1669.
  3. ^ Waller, Francis J.; Barrett, Anthony G. M.; Braddock, D. Christopher; Ramprasad, Dorai; McKinnell, R. Murray; White, Andrew J. P.; Williams, David J.; Ducray, Richard (1999-04-01). "Tris(trifluoromethanesulfonyl)methide ("Triflide") Anion:  Convenient Preparation, X-ray Crystal Structures, and Exceptional Catalytic Activity as a Counterion with Ytterbium(III) and Scandium(III)". The Journal of Organic Chemistry. 64 (8): 2910–2913. doi:10.1021/jo9800917. ISSN 0022-3263.
  4. ^ Ishihara, Kazuaki; Hiraiwa, Yukihiro; Yamamoto, Hisashi (2000-01-01). "Homogeneous Debenzylation Using Extremely Active Catalysts: Tris(triflyl)methane, Scandium(III) Tris(triflyl)methide, and Copper(II) Tris(triflyl)methide". Synlett. 2000 (01): 80–82. doi:10.1055/s-2000-6436. ISSN 0936-5214.
  5. ^ Johansson, Katarina M.; Adebahr, Josefina; Howlett, Patrick C.; Forsyth, Maria; MacFarlane, Douglas R. (2007-01-01). "N-Methyl-N-Alkylpyrrolidinium Bis(perfluoroethylsulfonyl)amide ([NPf2]) and Tris(trifluoromethanesulfonyl)methide ([CTf3]) Salts: Synthesis and Characterization". Australian Journal of Chemistry. 60 (1): 57–63. doi:10.1071/ch06299.