Triflidic acid

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 (pK_a^aq ~ –14), as measured by its acid dissociation constant. It was first prepared in 1987 by Seppelt and Turowsky by the following route:^[2]

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

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

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

Triflidic acid

Triflidic acid
Names
Preferred IUPAC name [Bis(trifluoromethanesulfonyl)methanesulfonyl]tri(fluoro)methane
Other names Triflidic acid, tris(triflyl)methane, tris[(trifluoromethyl)sulfonyl]methane
Identifiers
CAS Number	60805-12-1 Y
3D model (JSmol)	Interactive image
ChemSpider	3512136 Y
ECHA InfoCard	100.258.613
PubChem CID	4306514
CompTox Dashboard (EPA)	DTXSID40401774
InChI 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
SMILES [H]C(S(=O)(C(F)(F)F)=O)(S(=O)(C(F)(F)F)=O)S(=O)(C(F)(F)F)=O
Properties
Chemical formula	C4HF9O6S3
Molar mass	412.21 g·mol−1
Appearance	Colorless solid
Melting point	69.2 °C (156.6 °F; 342.3 K)
Solubility in water	Miscible
Acidity (pKa)	–18.6 (aqueous, est.)[1]
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Corrosive, eye irritant
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H314, H335
Precautionary statements	P260, P261, P264, P271, P280, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P312, P321, P363, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

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]

See also

• Bistriflimide
• Non-coordinating anion