Triflidic acid (IUPAC name: tris
trifluoromethyl)sulfonylethane, abbreviated formula: Tf
3CH) is an organic
superacid
In chemistry, a superacid (according to the original definition) is an acid with an acidity greater than that of 100% pure sulfuric acid (), which has a Hammett acidity function (''H''0) of −12. According to the modern definition, a superacid i ...
. 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 acid
Carborane acids (X, Y, Z = H, Alk, F, Cl, Br, CF3) are a class of superacids, some of which are estimated to be at least one million times stronger than 100% pure sulfuric acid in terms of their Hammett acidity function values (''H''0 ≤ −18 ...
s. Notably, triflidic acid is estimated to have an acidity 10
4 times that of
triflic acid
Triflic acid, the short name for trifluoromethanesulfonic acid, TFMS, TFSA, HOTf or TfOH, is a sulfonic acid with the chemical formula CF3SO3H. It is one of the strongest known acids. Triflic acid is mainly used in research as a catalyst for este ...
(p''K''
aaq ~ –14), as measured by its
acid dissociation constant
In chemistry, an acid dissociation constant (also known as acidity constant, or acid-ionization constant; denoted ) is a quantitative property, quantitative measure of the acid strength, strength of an acid in Solution (chemistry), solution. I ...
. It was first prepared in 1987 by
Seppelt and Turowsky by the following route:
:(1) Tf
2CH
2 + 2 CH
3MgBr → Tf
2C(MgBr)
2 + 2 CH
4
:(2) Tf
2C(MgBr)
2 + TfF → Tf
3C(MgBr) + MgBrF
:(3) Tf
3C(MgBr) + H
2SO
4 → Tf
3CH + MgBrHSO
4
In its anionic form, the lanthanide salts of triflidic acid ("triflides") have been shown to be more efficient Lewis acids than the corresponding triflates. The triflide anion has also been employed as the anionic component of ionic liquids.
See also
*
Bistriflimide
Bistriflimide, also known variously as bis(trifluoromethane)sulfonimide, bis(trifluoromethanesulfonyl)imide, bis(trifluoromethanesulfonyl)imidate (and variations thereof), informally and somewhat inaccurately as triflimide or triflimidate'','' or ...
*
Non-coordinating anion
Anions that interact weakly with cations are termed non-coordinating anions, although a more accurate term is weakly coordinating anion. Non-coordinating anions are useful in studying the reactivity of electrophilic cations. They are commonly foun ...
References
{{reflist
Superacids
Triflyl compounds