FLUOROSULFONIC ACID

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.

• Known Catalytic Activity
• Water-Reactive

Fumes in air. Reacts violently with water to form hydrogen fluoride and sulfuric acid mist.

Based on a scenario where the chemical is spilled into an excess of water (at least 5 fold excess of water), half of the maximum theoretical yield of Hydrogen Fluoride gas will be created in 0.12 minutes. Experimental details are in the following: "Development of the Table of Initial Isolation and Protective Distances for the 2008 Emergency Response Guidebook", ANL/DIS-09-2, D.F. Brown, H.M. Hartmann, W.A. Freeman, and W.D. Haney, Argonne National Laboratory, Argonne, Illinois, June 2009.

Special Hazards of Combustion Products: Toxic and irritating fumes of hydrogen fluoride and sulfuric acid may form in fires.

Behavior in Fire: Contact with water applied to adjacent fires produces toxic, irritating fumes of hydrogen fluoride. (USCG, 1999)

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. (USCG, 1999)

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.

• Acids, Strong Non-oxidizing
• Acyl Halides, Sulfonyl Halides, and Chloroformates
• Fluoride Salts, Soluble

Use caution: Liquids with this reactive group classification have been known to react with the absorbents listed below.

• Cellulose-Based Absorbents
• Mineral-Based & Clay-Based Absorbents
• Sand
• Dirt/Earth

Excerpt from 137 [Substances - Water-Reactive - Corrosive]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.

SPILL: See ERG Table 1 - Initial Isolation and Protective Action Distances on the UN/NA 1777 datasheet.

FIRE: If tank, rail car or tank truck is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2020)

Excerpt from 137 [Substances - Water-Reactive - Corrosive]:

When material is not involved in fire, do not use water on material itself.

SMALL FIRE: Dry chemical or CO2. If it can be done safely, move undamaged containers away from the area around the fire.

LARGE FIRE: Flood fire area with large quantities of water, while knocking down vapors with water fog. If insufficient water supply, responders should withdraw.

FIRE INVOLVING TANKS OR CAR/TRAILER LOADS: Cool containers with flooding quantities of water until well after fire is out. Do not get water inside containers. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks engulfed in fire. (ERG, 2020)

Excerpt from 137 [Substances - Water-Reactive - Corrosive]:

Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. Stop leak if you can do it without risk. Use water spray to reduce vapors; do not put water directly on leak, spill area or inside container. Keep combustibles (wood, paper, oil, etc.) away from spilled material.

SMALL SPILL: Cover with DRY earth, DRY sand or other non-combustible material followed with plastic sheet to minimize spreading or contact with rain. Use clean, non-sparking tools to collect material and place it into loosely covered plastic containers for later disposal. Prevent entry into waterways, sewers, basements or confined areas. (ERG, 2020)

Rubber gloves, shoes, and clothing; goggles and face shield; acid-type canister mask or air-line mask. (USCG, 1999)

Normalized Breakthrough Times (in Minutes)

Chemical	CAS Number	State	QS	QC	SL	C3	TF	TP	RC	TK	RF
Fluorosulfonic acid	7789-21-1	Liquid					194		>480	>480	>480

Special Warning from DuPont: Tychem® and Tyvek® fabrics should not be used around heat, flames, sparks or in potentially flammable or explosive environments. Only...

(DuPont, 2023)

Get medical attention quickly following all exposures to this compound.

INHALATION: remove victim to fresh air; if he is unconscious, give artificial respiration.

EYES: flush with water until medical help arrives.

SKIN: flush with water until medical help arrives; soak burned area in strong Epsom salt solution; pay particular attention to area around fingernails.

INGESTION: give large amounts of water. (USCG, 1999)

• FLUOROSULFONIC ACID
• FLUOROSULFURIC ACID
• FLUOROSULFURIC ACID (HSO3F)
• FLUOROSULPHONIC ACID
• FLUOSULFONIC ACID
• FLUOSULFURIC ACID
• MONOFLUOROSULFURIC ACID