Description
Concerns about the potential environmental and toxicological
impacts of long-chain perfluoroalkyl sulfonates and
carboxylic acids have led to: (1) the phaseout of production of
perfluorooctane sulfonate (PFOS) and related compounds
and perfluorooctanoic acid (PFOA) by their major global
manufacturer in 2000–02; (2) the conclusion of a stewardship
agreement between the United States Environmental Protection
Agency (US EPA) and eight leading global companies to
reduce emissions and product content of PFOA and related
chemicals by 95% by 2010 and to work toward their elimination
by 2015; (3) a similar agreement between the
Canadian environmental and health authorities and five
companies to restrict perfluorinated carboxylic acids in
products; (4) a European Union Marketing and Use Directive
restricting the use of ‘PFOSs’ in the European Union; and
(5) the inclusion of PFOS in the Stockholm Convention on
Persistent Organic Pollutants as an Annex B substance,
i.e., restricted in its use; and other regulatory and voluntary
initiatives intended to reduce environmental emissions of this
family of compounds.
Chemical Properties
Perfluorooctanoic acid is a white to off-white powder or colorless flakes. It is very soluble in water.It has a pH of 2.6. Perfluorooctanoic acid has the ability to react with bases, oxidizing agents, and reducing agents. Upon decomposition, PFOA can form carbon oxides and hydrogen fluoride. Additional information related to physical and chemical properties of PFOA are not currently available.
Uses
Pentadecafluorooctanoic acid solution may be used as an ion-pairing reagent in the development of a chromatographic method for the separation and determination of underivatized proteinic amino acids using liquid chromatography with evaporative light scattering detection (LC-ELSD) and atmospheric pressure ionization-mass spectrometry (LC-API-MS), respectively.
Uses
PFOA is a completely fluorinated organic acid that is
produced synthetically as its salts. The typical structure has
a nonbranched chain of eight carbon atoms. The industrial
production of perfluoroalkyl carboxylates started in the late
1940s. Two principal production processes are used to
manufacture PFOA, viz. electrochemical fluorination and
telomerization. PFOA can also appear as a result of degradation
of some precursors, e.g., fluorotelomer alcohols. The
ammonium salt of PFOA is primarily used as an emulsifier
or ‘processing aid’ in industrial applications, for example, in the production of fluoropolymers such as polytetrafluoroethylene,
but also produced for fluorosurfactant use. Typical
uses include fluoropolymers in electronics, textiles, and
nonstick cookware, and fluorosurfactants in aqueous filmforming
foams used for fire fighting.
Uses
Perfluorooctanoic acid (PFOA) is fluorinated surfactant used, primarily as its ammonium salt (APFO), as an aid in the chemical synthesis of fluoropolymers and fluoroelastomers. As such, it may be found in nonstick cookware and utensils, stain-repellant fabric treatments, and water-proofing treatments for garments. Although an effort is underway by the U.S. EPA to reduce use of and replace perfluoroalkyls with other substances, PFOA is still used in United States industry.
Perfluorooctanoic acid (PFOA, C8, pentadecafluorooctanoic acid, perfluoro caprylic acid) is an eightcarbon compound in the perfluoroalkyl family of chemicals. Perfluorooctane sulfonate is used in a variety of applications, including nonstick cookware, waterproof clothing, leather products, cleaning products, and pesticides. Its main use was as a stain repellent on carpet, furniture, and other consumer products. In 2006, the U.S. Protection Agency along with eight major companies that utilized PFOA embarked on a program to reduce emissions and use of the chemical by 2015 (USEPA, 2012).
Definition
ChEBI: A fluoroalkanoic acid that is perfluorinated octanoic acid.
General Description
Perfluorooctanoic acid is a perfluoroalkyl acid commonly used in the preparation of fluoroacrylic esters, fluoropolymers and fluoroelastmers. It is found to be environmentally persistent and bioaccumulative with a long half-life.
Safety Profile
Poison by intraperitoneal route. Mutation data reported. Whenheated to decomposition it emits toxic vapors of Fí.
Environmental Fate
Perfluorooctanoic acid found in the environment may result from waste stream releases from manufacture of cosmetics, lubricants, paints, polishes, adhesives, fabric treatments, and fire-fighting compounds. It can partition to the vapor phase in the atmosphere, where it is degraded atmospherically with a half-life of 31 days. It is very resistant to hydrolysis, and immobile in soil. It will not likely evaporate from soil (depending on soil pH) or surface waters. It is not expected to be absorbed to sediments and suspended particles. Perfluorooctanoic acid is not expected to bioaccumulate in aquatic organisms (BCF =3.1–9.4) (NLM, 2013).
Purification Methods
Crystallise the acid from CCl4 and toluene, and distil it. It forms micelles in H2O and the solubility is 1% in H2O. The acid chloride has b 129-130o/744mm. The amide has m 138o. [Bernett & Zisman J Phys Chem 63 1911 1959, Bro & Sperati J Polym Sci 38 289 1959, Beilstein 2 IV 994.]
Toxicity evaluation
Studies with animals fed PFOA for a long period showed effects
on the stomach, liver, and thyroid hormones. Animal studies
also indicate that PFOA may cause cancer at relatively high
levels. PFOA has also been shown to be a developmental
toxicant, and to have effects on the immune system.
PFOA affects primarily the liver and can cause developmental
and reproductive toxic effects at relatively low dose
levels in experimental animals. It increases the tumor incidence
in rats, mainly in the liver. The carcinogenic effects in rats
appear to be due to indirect/nongenotoxic modes of action.
Epidemiological studies in PFOA-exposed workers do not
indicate an increased cancer risk. There is relatively consistent
evidence of modest positive associations between serum levels
of PFOA and cholesterol, uric acid, and liver enzyme levels.
The critical effects observed in rodents and monkeys are on
the liver and include hypertrophy, changes in liver enzyme
activity, and proliferation of peroxisomes.
In rodents the anionic form of PFOA induces hepatocellular
adenomas, Leydig cell adenomas, and pancreatic hyperplasia.
The genotoxic activity of PFOA is a matter of current debate and
controversy, with classifications as ‘devoid of significant genotoxicity’
as well as ‘weakly nonspecific genotoxic.’ PFOA does
not appear directly genotoxic; animal data indicate that it can
cause several types of tumors and neonatal death and may have
toxic effects on the immune, liver, and endocrine systems.
Toxics Screening Level
The initial threshold screening level (ITSL) for perfluorooctanoic acid (PFOA) is 0.0001 μg/m3 with 24-hour averaging time.
