Perfluorononanoic acid
Encyclopedia
Perfluorononanoic acid, or PFNA, is a synthetic perfluorinated carboxylic acid
and fluorosurfactant
that is also an environmental contaminant found in people and wildlife along with PFOS and PFOA.
. In its conjugate base form as a salt
it is stable and commonly ion paired with ammonium
. In the commercial product Surflon S-111
(CAS 72968-3-88) it is the primary compound present by weight. PFNA is used as surfactant
for the production of the fluoropolymer
polyvinylidene fluoride
. It is produced mainly in Japan by the oxidation of a linear fluorotelomer
olefin mixture containing F(CF2)8CH=CH2. It can also be synthesized by the carboxylation
of F(CF2)8I. PFNA can form from the biodegradation
of 8:2 fluorotelomer alcohol
. Additionally, it is considered a probable degradation product of many other compounds.
PFNA is the largest perfluorinated carboxylic acid surfactant. Fluorocarbon derivatives with terminal carboxylates are only surfactants when they possess five to nine carbons. Fluorosurfactants reduce the surface tension
of water down to half of what hydrocarbon
surfactants can by concentrating at the liquid-air interface due to the lipophobicity
of fluorocarbons. PFNA is very stable and is not known to degrade in the environment by oxidative processes because of the strength of the carbon–fluorine bond
and the electronegativity
of fluorine
.
toxicant. However, longer chain perfluorinated carboxylic acid
s (PFCAs) are considered more bioaccumulative and toxic. PFNA is an agonist
of the nuclear receptors PPARα
and PPARγ. In the years between 1999–2000 and 2003–2004, the geometric mean
of PFNA increased from 0.5 parts per billion to 1.0 parts per billion in the US population's blood serum
. In a cross-sectional study
of 2003–2004 US samples, a higher (13.9 milligram per deciliter) total cholesterol level was observed in when the highest quartile
was compared to the lowest. Non-HDL cholesterol (or "bad cholesterol") levels were also higher in samples with more PFNA.
In bottlenose dolphins from Delaware Bay
, PFNA was the perfluorinated carboxylic acid measured in the highest concentration in blood plasma
; it was found in concentrations well over 100 parts per billion. PFNA has been detected in polar bears in concentrations over 400 parts per billion. PFNA was the perfluorinated chemical measured in the highest concentration in Russian Baikal seals. However, PFOS is the perfluorinated compound
that dominates in most wildlife biomonitoring
samples.
Perfluorinated carboxylic acid
Perfluorinated carboxylic acids , or perfluorocarboxylates are fully fluorinated organofluorine compounds—or perfluorinated compounds—with carboxylic acid or carboxylate functional groups. PFCAs are fluorocarbon derivatives...
and fluorosurfactant
Fluorosurfactant
Fluorosurfactants, or fluorinated surfactants, are synthetic organofluorine chemical compounds that have multiple fluorine atoms. They can be polyfluorinated or fluorocarbon-based . As surfactants, they are more effective at lowering the surface tension of water than comparable hydrocarbon...
that is also an environmental contaminant found in people and wildlife along with PFOS and PFOA.
Chemistry and properties
In acidic form it is a highly reactive strong acidAcid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...
. In its conjugate base form as a salt
Salt
In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...
it is stable and commonly ion paired with ammonium
Ammonium
The ammonium cation is a positively charged polyatomic cation with the chemical formula NH. It is formed by the protonation of ammonia...
. In the commercial product Surflon S-111
Surflon S-111
Surflon S-111 is a commercial product consisting of perfluorinated carboxylic acids in ammonium salt form. It is commonly used as a polymerization aid in the production of fluoropolymers....
(CAS 72968-3-88) it is the primary compound present by weight. PFNA is used as surfactant
Surfactant
Surfactants are compounds that lower the surface tension of a liquid, the interfacial tension between two liquids, or that between a liquid and a solid...
for the production of the fluoropolymer
Fluoropolymer
A fluoropolymer is a fluorocarbon based polymer with multiple strong carbon–fluorine bonds. It is characterized by a high resistance to solvents, acids, and bases.-History:Fluoropolymers were accidentally discovered in 1938 by Dr. Roy J...
polyvinylidene fluoride
Polyvinylidene fluoride
Polyvinylidene fluoride, or PVDF is a highly non-reactive and pure thermoplastic fluoropolymer.PVDF is a specialty plastic material in the fluoropolymer family; it is used generally in applications requiring the highest purity, strength, and resistance to solvents, acids, bases and heat and low...
. It is produced mainly in Japan by the oxidation of a linear fluorotelomer
Fluorotelomer
Fluorotelomers are fluorocarbon-based oligomers, or telomers, synthesized by telomerization. Some fluorotelomers and fluorotelomer-based compounds are a source of environmentally persistent perfluorinated carboxylic acids such as PFOA and PFNA, while others are under extended...
olefin mixture containing F(CF2)8CH=CH2. It can also be synthesized by the carboxylation
Carboxylation
Carboxylation in chemistry is a chemical reaction in which a carboxylic acid group is introduced in a substrate. The opposite reaction is decarboxylation.-Carboxylation in organic chemistry:In organic chemistry many different protocols exist for carboxylation...
of F(CF2)8I. PFNA can form from the biodegradation
Biodegradation
Biodegradation or biotic degradation or biotic decomposition is the chemical dissolution of materials by bacteria or other biological means...
of 8:2 fluorotelomer alcohol
Fluorotelomer alcohol
Fluorotelomer alcohols, or FTOHs, are fluorotelomers with an alcohol functional group. They are volatile precursors to perfluorinated carboxylic acids, such as PFOA and PFNA, and other compounds.-Naming:...
. Additionally, it is considered a probable degradation product of many other compounds.
PFNA is the largest perfluorinated carboxylic acid surfactant. Fluorocarbon derivatives with terminal carboxylates are only surfactants when they possess five to nine carbons. Fluorosurfactants reduce the surface tension
Surface tension
Surface tension is a property of the surface of a liquid that allows it to resist an external force. It is revealed, for example, in floating of some objects on the surface of water, even though they are denser than water, and in the ability of some insects to run on the water surface...
of water down to half of what hydrocarbon
Hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....
surfactants can by concentrating at the liquid-air interface due to the lipophobicity
Lipophobicity
Lipophobicity, also sometimes called lipophobia, is a chemical property of chemical compounds which means "fat rejection", literally "fear of fat". Lipophobic compounds are those not soluble in lipids or other non-polar solvents...
of fluorocarbons. PFNA is very stable and is not known to degrade in the environment by oxidative processes because of the strength of the carbon–fluorine bond
Carbon–fluorine bond
The carbon–fluorine bond is a bond between carbon and fluorine that is a component of all organofluorine compounds. It is the strongest single bond in organic chemistry—and relatively short—due to its partial ionic character. The bond also strengthens and shortens as more fluorines are...
and the electronegativity
Electronegativity
Electronegativity, symbol χ , is a chemical property that describes the tendency of an atom or a functional group to attract electrons towards itself. An atom's electronegativity is affected by both its atomic number and the distance that its valence electrons reside from the charged nucleus...
of fluorine
Fluorine
Fluorine is the chemical element with atomic number 9, represented by the symbol F. It is the lightest element of the halogen column of the periodic table and has a single stable isotope, fluorine-19. At standard pressure and temperature, fluorine is a pale yellow gas composed of diatomic...
.
Environmental and health concerns
Like the eight-carbon PFOA, the nine-carbon PFNA is a developmental toxicant and an immune systemImmune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...
toxicant. However, longer chain perfluorinated carboxylic acid
Perfluorinated carboxylic acid
Perfluorinated carboxylic acids , or perfluorocarboxylates are fully fluorinated organofluorine compounds—or perfluorinated compounds—with carboxylic acid or carboxylate functional groups. PFCAs are fluorocarbon derivatives...
s (PFCAs) are considered more bioaccumulative and toxic. PFNA is an agonist
Agonist
An agonist is a chemical that binds to a receptor of a cell and triggers a response by that cell. Agonists often mimic the action of a naturally occurring substance...
of the nuclear receptors PPARα
Peroxisome proliferator-activated receptor
In the field of molecular biology, the peroxisome proliferator-activated receptors are a group of nuclear receptor proteins that function as transcription factors regulating the expression of genes...
and PPARγ. In the years between 1999–2000 and 2003–2004, the geometric mean
Geometric mean
The geometric mean, in mathematics, is a type of mean or average, which indicates the central tendency or typical value of a set of numbers. It is similar to the arithmetic mean, except that the numbers are multiplied and then the nth root of the resulting product is taken.For instance, the...
of PFNA increased from 0.5 parts per billion to 1.0 parts per billion in the US population's blood serum
Blood serum
In blood, the serum is the component that is neither a blood cell nor a clotting factor; it is the blood plasma with the fibrinogens removed...
. In a cross-sectional study
Cross-sectional study
Cross-sectional studies form a class of research methods that involve observation of all of a population, or a representative subset, at one specific point in time...
of 2003–2004 US samples, a higher (13.9 milligram per deciliter) total cholesterol level was observed in when the highest quartile
Quartile
In descriptive statistics, the quartiles of a set of values are the three points that divide the data set into four equal groups, each representing a fourth of the population being sampled...
was compared to the lowest. Non-HDL cholesterol (or "bad cholesterol") levels were also higher in samples with more PFNA.
In bottlenose dolphins from Delaware Bay
Delaware Bay
Delaware Bay is a major estuary outlet of the Delaware River on the Northeast seaboard of the United States whose fresh water mixes for many miles with the waters of the Atlantic Ocean. It is in area. The bay is bordered by the State of New Jersey and the State of Delaware...
, PFNA was the perfluorinated carboxylic acid measured in the highest concentration in blood plasma
Blood plasma
Blood plasma is the straw-colored liquid component of blood in which the blood cells in whole blood are normally suspended. It makes up about 55% of the total blood volume. It is the intravascular fluid part of extracellular fluid...
; it was found in concentrations well over 100 parts per billion. PFNA has been detected in polar bears in concentrations over 400 parts per billion. PFNA was the perfluorinated chemical measured in the highest concentration in Russian Baikal seals. However, PFOS is the perfluorinated compound
Perfluorinated compounds
A perfluorinated compound is an organofluorine compound with all hydrogens replaced by fluorine on a carbon chain—but the molecule also contains at least one different atom or functional group. Thus, PFCs have properties similar to fluorocarbons as they are fluorocarbon derivatives...
that dominates in most wildlife biomonitoring
Biomonitoring
Aquatic biomonitoring is the science of inferring the ecological condition of rivers, lakes, streams, and wetlands by examining the organisms that live there...
samples.
External links
- Perfluorocarboxylic Acid Content in 116 Articles of Commerce PDF
- Centers for Disease Control and Prevention, Polyfluorochemicals fact sheet
- Perfluorinated substances and their uses in Sweden
- Perfluoroalkylated substances, Aquatic environmental assessment
- Chain of Contamination: The Food Link, Perfluorinated Chemicals (PFCs) Incl. PFOS & PFOA