Title: Triflic Acid
CAS Registry Number: 1493-13-6
CAS Name: Trifluoromethanesulfonic acid
Synonyms: TFMSA
Molecular Formula: CHF3O3S
Molecular Weight: 150.08
Percent Composition: C 8.00%, H 0.67%, F 37.98%, O 31.98%, S 21.37%
Line Formula: F3CSO2OH
Literature References: One of the strongest acids known. Prepn: R. N. Haszeldine, J. M. Kidd,
J. Chem. Soc. 1954, 4228. Acid-base equilibria study: Y. Y. Fialkov, V. I. Ligus,
J. Gen. Chem. USSR 42, 256 (1972). Deprotecting agent in peptide chemistry: H. Yajima
et al., J. Chem. Soc. Chem. Commun. 1974, 107. Hammett acidity function: S. Saito
et al., Chem. Pharm. Bull. 39, 2718 (1991). Electrochemical determn of ionic form: F. Favier, J. L. Pascal,
Analyst 116, 479 (1991). Ion chromatographic determn of triflic and trifluoroacetic acids: N. Simonzadeh,
J. Chromatogr.634, 125 (1993).
Reviews: R. D. Howells, J. D. McCown,
Chem. Rev. 77, 69-92 (1977); P. J. Stang, M. R. White,
Aldrichim. Acta 16, 15-22 (1983).
Properties: Clear, colorless, hygroscopic liquid, bp760 162°; bp57.5 91°; bp37.5 81°; bp1 42°. d25 1.6980.
nD25 1.325. Miscible with water; sol in alcohols, ketones, ethers, esters and many other polar organic solvents. Viscosity at 25°: 2.87 cP. Electrical conductivity at 25°: 2 ′ 10-4 W-1 cm-1. Thermally stable; nonoxidizing.
Boiling point: bp760 162°; bp57.5 91°; bp37.5 81°; bp1 42°
Index of refraction: nD25 1.325
Density: d25 1.6980
CAUTION: Direct contact may cause skin burns (Haszeldine).
Use: As a catalyst in Friedel-Crafts type acylation, alkylation and polymerization reactions; as a solvent for ESR; as a nonaqueous strong acid titrant; with trifluoroacetic acid,
q.v., in solid-phase peptide synthesis.
