Nonylphenol
Encyclopedia
Nonylphenol is a family of closely related organic compound
Organic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...

s, a subset of the alkylphenol
Alkylphenol
Alkylphenols are a family of organic compounds obtained by the alkylation of phenols. The term is usually reserved for commercially important propylphenol, butylphenol, amylphenol, heptylphenol, octylphenol, nonylphenol, dodecylphenol and related "long chain alkylphenols"...

s. This collection of compounds is a precursor to commercially important detergents. Nonylphenol features both polar and hydrophobic subunits, the phenol
Phenol
Phenol, also known as carbolic acid, phenic acid, is an organic compound with the chemical formula C6H5OH. It is a white crystalline solid. The molecule consists of a phenyl , bonded to a hydroxyl group. It is produced on a large scale as a precursor to many materials and useful compounds...

 and the hydrocarbon tail.

Production and basic properties

The material known collectively as nonylphenol is produced by acid-catalyzed alkylation
Alkylation
Alkylation is the transfer of an alkyl group from one molecule to another. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion or a carbene . Alkylating agents are widely used in chemistry because the alkyl group is probably the most common group encountered in...

 of phenol
Phenol
Phenol, also known as carbolic acid, phenic acid, is an organic compound with the chemical formula C6H5OH. It is a white crystalline solid. The molecule consists of a phenyl , bonded to a hydroxyl group. It is produced on a large scale as a precursor to many materials and useful compounds...

 with a mixture of nonene
Nonene
Nonene is an alkene with the molecular formula C9H18. Many structural isomers are possible, depending on the location of the C=C double bond and the branching of the other parts of the molecule. Industrially, the most important nonenes are trimers of propene...

s. Millions of kilograms are produced annually. The nonyl group, which is highly branched, attaches to the phenol ring via the 4- and, to lesser extent, the 2-positions. This mixture of isomers is usually available as a pale yellow liquid, although the pure compounds are colorless. The organic compound 1-nonyl-4-phenol
1-Nonyl-4-phenol
1-Nonyl-4-phenol is an organic compound consisting of a n-nonyl group attached to the 4-position of phenol. The related nonylphenols with branched nonyl groups are commercially important detergents....

 is not normally a component of what is marketed as nonylphenol. The nonylphenols are poorly soluble in water but soluble in alcohol.

In the environment, nonylphenols arise from the degradation of the nonaphenol ethoxylates, which are detergents.

Nonylphenol has been found to be a component of the slime produced by the velvet worm as a defence mechanism.

Applications

Alkylphenols are subjected to ethoxylation
Ethoxylation
Ethoxylation is an industrial process in which ethylene oxide is added to alcohols and phenols to give surfactants. The invention of the process is attributed to Schöller and Wittwer at I.G. Farben industrie.-Production:...

 to give alkylphenol ethoxylates (APEs), which are widely used as industrial 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...

s. They are used in applications as disparate as the processing of wool and metals, as emulsifiers for emulsion polymerization
Emulsion polymerization
Emulsion polymerization is a type of radical polymerization that usually starts with an emulsion incorporating water, monomer, and surfactant. The most common type of emulsion polymerization is an oil-in-water emulsion, in which droplets of monomer are emulsified in a continuous phase of water...

, as laboratory detergent
Detergent
A detergent is a surfactant or a mixture of surfactants with "cleaning properties in dilute solutions." In common usage, "detergent" refers to alkylbenzenesulfonates, a family of compounds that are similar to soap but are less affected by hard water...

s, and as pesticide
Pesticide
Pesticides are substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest.A pesticide may be a chemical unicycle, biological agent , antimicrobial, disinfectant or device used against any pest...

s. APEs are a component of some household detergents outside of Europe. In Europe, due to environmental concerns, they have been replaced by more expensive alcohol ethoxylates, which are less problematic environmentally. Nonoxynol-9
Nonoxynol-9
Nonoxynol-9, sometimes abbreviated as N-9, is an organic compound that is used as a surfactant. It is a member of the nonoxynol family of nonionic surfactants. N-9 and related compounds are ingredients in various cleaning and cosmetic products. It is widely used in contraceptives for its...

, one of the APEs, is used as a surfactant in cleaning and cosmetic products, and as a spermicide
Spermicide
Spermicide is a contraceptive substance that eradicates sperm, inserted vaginally prior to intercourse to prevent pregnancy. As a contraceptive, spermicide may be used alone. However, the pregnancy rate experienced by couples using only spermicide is higher than that of couples using other methods...

 in contraceptives.

Health and environmental hazards

Nonylphenol is considered to be an endocrine disruptor
Endocrine disruptor
Endocrine disruptors are chemicals that interfere with endocrine in animals, including humans. These disruptions can cause cancerous tumors, birth defects, and other developmental disorders...

 due to weak ability to mimic estrogen and in turn disrupt the natural balance of hormones in affected organisms. The effect is weak because nonylphenols are not very close structural mimics of estradiol, but the levels of nonylphenol can be sufficiently high to compensate.

Occurrence in the environment

Nonylphenols have been detected widely in waste water streams across the globe, which is a concern since it is toxic to many aquatic organisms. In the US, nonylphenols have been detected both in the Great Lakes and in the region of New York City. In 1984, the formation of 4-nonylphenols from nonylphenol ethoxylates in wastewater treatment plants
Sewage treatment
Sewage treatment, or domestic wastewater treatment, is the process of removing contaminants from wastewater and household sewage, both runoff and domestic. It includes physical, chemical, and biological processes to remove physical, chemical and biological contaminants...

was first discovered. Nonylphenol is persistent in the environment, therefore lingers with the potential to negatively affect organisms it comes in contact with.

Environmental protection policies

Nonylphenol and nonyphenol ethoxylates have been restricted in the European Union as a hazard to human and environmental safety.

For freshwater ecosystems, the Environmental Protection Agency has set two types of standards: the first which is considered acute criteria is one-hour average concentration of nonylphenol does not exceed 28 μg/L more than once every three years on the average.

For saltwater ecosystems, the standard is considered to be chronic criteria and is set to four-day average concentration of nonylphenol that does not exceed 6.6 μg/l more than once every three years on the average.
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