Alkylphenols are a family of organic compounds obtained by the alkylation of
phenol
Phenol (also known as carbolic acid, phenolic acid, or benzenol) is an aromatic organic compound with the molecular formula . It is a white crystalline solid that is volatile and can catch fire.
The molecule consists of a phenyl group () ...
s. The term is usually reserved for commercially important propylphenol, butylphenol, amylphenol, heptylphenol, octylphenol,
nonylphenol
Nonylphenols are a family of closely related organic compounds composed of phenol bearing a 9 carbon-tail. Nonylphenols can come in numerous structures, all of which may be considered alkylphenols. They are used in manufacturing antioxidants, l ...
, dodecylphenol and related "long chain alkylphenols" (LCAPs). Methylphenols and ethylphenols are also alkylphenols, but they are more commonly referred to by their specific names, cresols and xylenols.
Some members of this group of compounds have proven controversial.
Production and use
The long-chain alkylphenols are prepared by
alkylation Alkylation is a chemical reaction that entails transfer of an alkyl group. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion, or a carbene (or their equivalents). Alkylating agents are reagents for effecting al ...
of
phenol
Phenol (also known as carbolic acid, phenolic acid, or benzenol) is an aromatic organic compound with the molecular formula . It is a white crystalline solid that is volatile and can catch fire.
The molecule consists of a phenyl group () ...
with
alkenes
In organic chemistry, an alkene, or olefin, is a hydrocarbon containing a carbon–carbon double bond. The double bond may be internal or at the terminal position. Terminal alkenes are also known as Alpha-olefin, α-olefins.
The Internationa ...
:
:C
6H
5OH + RR'C=CH2 → RR'CH−CH
2−C
6H
4OH
In this way, about 500M kg/y are produced. Alkylphenols ethoxylates are common surfactants. Long-chain alkylphenols are used extensively as precursors to detergents. By condensation with formaldehyde, some alkylphenols are components in
phenolic resins.
[ These compounds are also used as building-block chemicals in making fragrances, thermoplastic elastomers, antioxidants, oil field chemicals, and fire retardant materials. As plastizers and antioxidants, alkylphenols are also found in tires, adhesives, coatings, carbonless copy paper and high performance rubber products.
]
Environmental controversy over nonylphenols
Alkylphenols are xenoestrogens
Xenoestrogens are a type of xenohormone that imitates estrogen. They can be either synthetic or natural chemical compounds. Synthetic xenoestrogens include some widely used industrial compounds, such as PCBs, BPA, and phthalates, which have ...
.nonylphenol
Nonylphenols are a family of closely related organic compounds composed of phenol bearing a 9 carbon-tail. Nonylphenols can come in numerous structures, all of which may be considered alkylphenols. They are used in manufacturing antioxidants, l ...
s are used because of their "toxicity, persistence, and the liability to bioaccumulate" but the United States EPA has taken a slower approach.[European Bans on Surfactant Trigger Transatlantic Debate]
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References
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