Fluorosulfonic Acid

Title: Fluorosulfonic Acid
CAS Registry Number: 7789-21-1
CAS Name: Fluorosulfuric acid
Additional Names: fluosulfonic acid
Molecular Formula: FHO3S
Molecular Weight: 100.07
Percent Composition: F 18.99%, H 1.01%, O 47.96%, S 32.04%
Line Formula: HSO3F
Literature References: Prepn: Thorpe, Kirman, J. Chem. Soc. 61, 921 (1892); Meyer, Schramm, Z. Anorg. Allg. Chem. 206, 25 (1932); Kwasnik in Handbook of Preparative Inorganic Chemistry vol. 1, G. Brauer, Ed. (Academic Press, New York, 2nd ed., 1963) pp 177-178. Reviews of properties and chemistry: Gillespie, Acc. Chem. Res. 1, 202-209 (1968); Thompson, "Fluorosulfuric Acid" in Inorganic Sulfur Chemistry, G. Nickless, Ed. (Elsevier, New York, 1968) pp 587-606; Jache in Adv. Inorg. Chem. Radiochem. 16, 177-200 (1974).
Properties: Colorless liquid; fumes in moist air. d418 1.740; d425 1.726. mp -89°. bp760 163°; bp120 110.0°; bp19 77.0°. Stable to 900°. Considerably more acidic than 100% H2SO4. Does not attack glass when anhydr and pure. Violent reaction with water although it is incompletely and reversibly hydrolyzed. Reddish-brown color with acetone. Forms stable salts which are little hydrolyzed by water and which may be recrystallized from water.
Melting point: mp -89°
Boiling point: bp760 163°; bp120 110.0°; bp19 77.0°
Density: d418 1.740; d425 1.726
Derivative Type: Methyl ester see Methyl Fluorosulfonate
CAUTION: May be highly irritating to skin, mucous membranes.
Use: Fluorinating agent. Catalyst in alkylation, acylation, polymerization and condensation reactions; in hydrofluorination of olefins; in production of substituted pyridines. In production of petroleum products. See Thompson, loc. cit. Magic Acid (Cationics) , a 1:1 HSO3F-SbF5 soln, is used in the study of stable solns of alkyl- and arylcarbonium ions: Olah, Science 168, 1298 (1970).
Fluorotoluene Fluorouracil Fluosilicic Acid Fluosol DA Fluoxastrobin