Perfluorooctanesulfonic acid

January 28, 2019
I’m a bad actor that makes excellent foams.
What molecule am I?

Perfluorooctanesulfonic acid, usually abbreviated to PFOS, was once a widely used surfactant in fabric protectors, firefighting foams, and photolithographic chemical mixtures. It was introduced in 1949 by 3M Co. (then known as Minnesota Mining and Manufacturing Co.).

By 1968, traces of PFOS began to appear in human blood. 3M began to phase it out in 2000, but it and similar perfluorinated compounds continue to be produced in China.

Because of the multiple hazards imposed by PFOS and its cousins (see hazard information box), efforts have been made to develop lower fluorine content or fluorine-free foams for several years. Specifically, perfluorinated C6 surfactants have lower toxicological and environmental profiles than the C8s. Some of the C6s meet US military foam standards.

Thus far, the C6 products have significantly outperformed fluorine-free surfactants. But the pressure is on to develop better non-fluorine foams because last year Congress passed, and the president signed, an act that allows civilian airports to use these foams to fight fires.

Perfluorooctanesulfonic acid fast facts

CAS Reg. No. 1763-23-1
Empirical formula C8HF17O3S
Molar mass 500.13 g/mol
Appearance White powder
Melting point 90 ºC
Boiling point 258–260 ºC
Water solubility 680 mg/L

Perfluorooctanesulfonic acid hazard information

GHS classification*: corrosive to metals, category 1
H290—May be corrosive to metals   Chemical Safety Warning
GHS classification: acute toxicity, oral, category 3
H301—Toxic if swallowed Chemical Safety Warning
GHS classification: skin corrosion, category 1B
H314—Causes severe skin burns and eye damage Chemical Safety Warning
GHS classification: serious eye damage, category 1
H318—Causes serious eye damage Chemical Safety Warning
GHS classification: acute toxicity, inhalation, category 4
H332—Harmful if inhaled Chemical Safety Warning
GHS classification: carcinogenicity, category 2
H351—Suspected of causing cancer Chemical Safety Warning
GHS classification: reproductive toxicity, category 1A
H360—May damage fertility or the unborn child Chemical Safety Warning
GHS classification: hazardous to the aquatic environment, acute hazard, category 2
H401—Toxic to aquatic life
GHS classification: hazardous to the aquatic environment, long-term hazard, category 2
H411—Toxic to aquatic life with long-lasting effects Chemical Safety Warning

*Globally Harmonized System of Classification and Labeling of Chemicals. Explanation of pictograms.

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