''tert''-Butylhydroquinone (TBHQ, tertiary butylhydroquinone) is a synthetic

aromatic In chemistry, aromaticity is a chemical property of cyclic ( ring-shaped), ''typically'' planar (flat) molecular structures with pi bonds in resonance (those containing delocalized electrons) that gives increased stability compared to satur ...

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. T ...

which is a type of

phenol Phenol (also called carbolic acid) is an aromatic organic compound with the molecular formula . It is a white crystalline solid that is volatile. The molecule consists of a phenyl group () bonded to a hydroxy group (). Mildly acidic, it ...

. It is a derivative of

hydroquinone Hydroquinone, also known as benzene-1,4-diol or quinol, is an aromatic organic compound that is a type of phenol, a derivative of benzene, having the chemical formula C6H4(OH)2. It has two hydroxyl groups bonded to a benzene ring in a ''para' ...

, substituted with a ''tert''-

butyl In organic chemistry, butyl is a four- carbon alkyl radical or substituent group with general chemical formula , derived from either of the two isomers (''n''-butane and isobutane) of butane. The isomer ''n''-butane can connect in two ways, gi ...

group.

Applications

Food preservative

In foods, TBHQ is used as a

preservative A preservative is a substance or a chemical that is added to products such as food products, beverages, pharmaceutical drugs, paints, biological samples, cosmetics, wood, and many other products to prevent decomposition by microbial growth or by ...

for unsaturated

vegetable oil Vegetable oils, or vegetable fats, are oils extracted from seeds or from other parts of fruits. Like animal fats, vegetable fats are ''mixtures'' of triglycerides. Soybean oil, grape seed oil, and cocoa butter are examples of seed oils, or f ...

s and many edible animal fats. It does not cause discoloration even in the presence of iron, and does not change flavor or odor of the material to which it is added. It can be combined with other preservatives such as

butylated hydroxyanisole Butylated hydroxyanisole (BHA) is a synthetic, waxy, solid petrochemical. Its antioxidant properties have caused it to be widely used as a preservative in food, food packaging, animal feed, cosmetics, pharmaceuticals, rubber, and petroleum produ ...

(BHA). As a food additive, its

E number E numbers ("E" stands for "Europe") are codes for substances used as food additives, including those found naturally in many foods such as vitamin C, for use within the European Union (EU) and European Free Trade Association (EFTA). Commonly ...

is E319. It is added to a wide range of foods. Its primary advantage is extending storage life.''Fats and oils: formulating and processing for applications'', Richard D. O'Brien, page 168

Other

In perfumery, it is used as a fixative to lower the evaporation rate and improve stability. It is used industrially as a stabilizer to inhibit autopolymerization of organic peroxides. It is used as an antioxidant in biodiesel. It is also added to varnishes, lacquers,

resin In polymer chemistry and materials science, resin is a solid or highly viscous substance of plant or synthetic origin that is typically convertible into polymers. Resins are usually mixtures of organic compounds. This article focuses on n ...

s, and oil-field additives.

Safety and regulation

The

European Food Safety Authority The European Food Safety Authority (EFSA) is the agency of the European Union (EU) that provides independent scientific advice and communicates on existing and emerging risks associated with the food chain. EFSA was established in February 2002, ...

(EFSA) and the

United States Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food s ...

(FDA) have evaluated TBHQ and determined that it is safe to consume at the concentration allowed in foods."Opinion of the Scientific Panel on food additives, flavourings, processing aids and materials in contact with food (AFC) on a request from the Commission related to tertiary-Butylhydroquinone (TBHQ)"

, 12 July 2004 The FDA21 C.F.R. § 172.185
/ref> and European Union both set an upper limit of 0.02% (200mg/kg) of the oil or fat content in foods. At very high doses, it has some negative health effects on lab animals, such as producing precursors to stomach tumors and damage to DNA. A number of studies have shown that prolonged exposure to very high doses of TBHQ may be carcinogenic, especially for stomach tumors. Other studies, however, have shown opposite effects including inhibition against HCA-induced carcinogenesis (by depression of metabolic activation) for TBHQ and other phenolic antioxidants (TBHQ was one of several, and not the most potent). The EFSA considers TBHQ to be noncarcinogenic. A 1986 review of scientific literature concerning the toxicity of TBHQ determined that a wide margin of safety exists between the levels of intake by humans and the doses that produce adverse effects in animal studies. There have been reports of vision disturbances in individuals exposed to this chemical. In addition, TBHQ has been identified by high-throughput screening as having potential immunotoxic effects. Not only that, over time, the chemical can be linked to hyperactivity (worsening the symptoms of ADHD), arthritis, rhinitis, dermatitis, and asthma. It is banned in Japan,

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the European mainland, continental mainland. It comprises England, Scotlan ...

, and other European countries.

References

{{DEFAULTSORT:Butylhydroquinone, Tert- Hydroquinones Food additives Food antioxidants Preservatives Alkylphenols Tert-butyl compounds E-number additives