perfluorooctanesulfonamide

Perfluorooctanesulfonamide (PFOSA) is a synthetic organofluorine compound. It is a fluorocarbon derivative and a perfluorinated compound, having an eight-carbon chain and a terminal sulfonamide functional group. PFOSA, a persistent organic pollutant, was an ingredient in 3M's former Scotchgard formulation from 1956 until 2003, and the compound was used to repel grease and water in food packaging along with other consumer applications. It breaks down to form perfluorooctane sulfonate (PFOS). PFOSA can be synthesized via the nucleophilic substitution of POSF with liquid ammonia or by a two step reaction via an azide followed by reduction with Zn and HCl. PFOSA is also a metabolic by-product of N-alkylated perfluorooctanesulfonamides. For example, N-ethyl perfluorooctanesulfonamidoethanol (N-EtFOSE), which was primarily used on paper, and N-methyl perfluorooctanesulfonamidoethanol (N-MeFOSE), which was primarily used on carpets and textiles, both metabolize via acetates to PFOSA.

In addition, PFOSA is thought to be the biologically active form of the insecticide Sulfluramid (N-ethyl perfluorooctanesulfonamide) as it is an extremely potent uncoupler of oxidative phosphorylation with an IC50 of about 1 micromolar (≈500 nanograms per milliliter or parts per billion). PFOSA was the most toxic perfluorinated compound in a study with PC12 cells. Concentrations ranged from 10 to 250 micromolar in the study (or 5000 to 125,000 parts per billion).