Description
Fluorosulphuric acid (FSO3H) is a free-flowing colourless fuming liquid. It is soluble in
polar organic solvents such as acetic acid, ethyl acetate, and nitrobenzene but poorly soluble
in nonpolar solvents such as alkanes. FSO3H is corrosive to metals and body tissues,
corrodes glass, and is incompatible with many metals and bases. With its strong
acidity, FSO3H dissolves almost all organic compounds that are even weak proton acceptors.
FSO3H hydrolyses slowly to HF and sulphuric acid (H2SO4). The related triflic acid
(CF3SO3H) retains the high acidity of FSO3H but is more hydrolytically stable. FSO3H is one
of the strongest known simple Bronsted acids. FSO3H is useful for regenerating mixtures
of HF and H2SO4 for etching lead glass. FSO3H isomerises alkanes and the alkylation of
hydrocarbons with alkenes, although it is unclear if such applications are of commercial
importance. FSO3H is used as a catalyst in organic synthesis and in electroplating and as
a fluorinating agent and as a laboratory fluorinating agent. FSO3H has been reported as
a highly toxic and corrosive chemical substance. FSO3H is non-combustible but enhances
combustion of other substances. It gives off irritating or toxic fumes (or gases) in a fire.
FSO3H hydrolyses to release HF. Addition of water to FSO3H causes very violent reactions
similar to the addition of water to H2SO4. Addition of FSO3H to water is a much more violent
process than addition of H2SO4. The combination of FSO3H and others is categorised
as ‘magic acids and super acids’. Very short contact and the fumes of FSO3H cause severe
painful burns.
Chemical Properties
colourless liquid
Uses
Catalyst in organic synthesis, electropolishing,
fluorinating agent.
Definition
ChEBI: Fluorosulfonic acid is a sulfur oxoacid.
General Description
A fuming liquid. Boiling point 163°C. Density 1.73 g / cm3. Corrosive to metals and to tissue. Both very short contact and the fumes can cause severe painful burns. Used as a catalyst in organic synthesis, in electroplating and as a fluorinating agent.
Air & Water Reactions
Fumes in air. Reacts violently with water to form hydrogen fluoride and sulfuric acid mist.
Reactivity Profile
FLUOROSULFONIC ACID is very strongly acidic [Merck]. Reacts exothermically with chemical bases (examples: amines, amides, and inorganic hydroxides). These reactions can generate dangerously large amounts of heat in small spaces. Reacts violently with water to generate hydrofluoric acid and sulfuric acid. Reacts with active metals, including such structural metals as aluminum and iron, to release hydrogen, a flammable gas. Can initiate the polymerization of certain alkenes. Reacts with cyanide compounds to release gaseous hydrogen cyanide. Generates flammable and/or toxic gases in contact with dithiocarbamates, isocyanates, mercaptans, nitrides, nitriles, sulfides, and strong reducing agents. Additional gas-generating reactions occur with sulfites, nitrites, thiosulfates (to give H2S and SO3), dithionites (SO2), and carbonates. May catalyze (increase the rate of) chemical reactions.
Hazard
Extremely irritating to eyes and tissue.
Health Hazard
Inhalation of fumes causes severe irritation of nose and throat. Contact of liquid with eyes or skin causes very severe burns of mouth and stomach.
Safety Profile
Probably a poison by
inhalation. A corrosive irritant to the skin,
eyes, and mucous membranes. See also
FLUORIDES, SULFURIC ACID, and
FLUOROSULFONATES.
