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Butylated hydroxytoluene

|Section2={{Chembox Properties | C=15 | H=24 | O=1 | Appearance = White to yellow powder | Odor = slight, phenolic | Density = 1.048 g/cm3 | Solubility = 1.1 mg/L (20 °C) KEMI – Swedish Chemicals Agency – read the 1'st of Marts 2010 on | MeltingPtC = 70 | MeltingPt_notes = BUTYLATED HYDROXYTOLUENE (ICSC) | BoilingPtC = 265 | BoilingPt_notes = | pKa = | VaporPressure = 0.01 mmHg (20°C) }} |Section7={{Chembox Hazards | ExternalSDS = External MSDS | NFPA-H = 2 | NFPA-F = 1 | NFPA-R = 0 | NFPA-S = | MainHazards = Flammable | FlashPtC = 127 | FlashPt_notes = | RPhrases = --- | SPhrases = - | PEL = none | IDLH = N.D. | REL = TWA 10 mg/m3 }} |Section8={{Chembox Related | OtherCompounds = Butylated hydroxyanisole }} }} Butylated hydroxytoluene (BHT), also known as dibutylhydroxytoluene, is a lipophilic organic compound, chemically a derivative of phenol, that is useful for its antioxidant properties. European and U.S. regulations allow small amounts to be used as a food additive. In addition to this use, BHT is widely used to prevent oxidation in fluids (e.g. fuel, oil) and other materials where free radicals must be controlled.

Occurrence

Phytoplankton, including the green algae Botryococcus braunii, as well as three different cyanobacteria ( Cylindrospermopsis raciborskii, Microcystis aeruginosa and Oscillatoria sp.) are capable of producing BHT. Confirmation was made via gas chromatography–mass spectrometry analysis.

Production

Industrially, BHT is prepared by the reaction of p-cresol (4-methylphenol) with isobutylene (2-methylpropene) catalyzed by sulfuric acid: Helmut Fiege, Heinz-Werner Voges, Toshikazu Hamamoto, Sumio Umemura, Tadao Iwata, Hisaya Miki, Yasuhiro Fujita, Hans-Josef Buysch, Dorothea Garbe, Wilfried Paulus "Phenol Derivatives" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2002. Article Online Posting Date: June 15, 2000. CH3(C6H4)OH + 2 CH2=C(CH3)2 → ((CH3)3C)2CH3C6H2OH Alternatively, BHT is prepared from 2,6-di-tert-butylphenol by hydroxymethylation or aminomethylation followed by hydrogenolysis.

Reactions

The species behaves as a synthetic analog of vitamin E, primarily acting as a terminating agent that suppresses autoxidation, a process whereby unsaturated (usually) organic compounds are attacked by atmospheric oxygen. BHT stops this autocatalytic reaction by converting peroxy radicals to hydroperoxides. It effects this function by donating a hydrogen atom: RO2. + ArOH → ROOH + ArO. RO2. + ArO. → nonradical products where R is alkyl or aryl, and where ArOH is BHT or related phenolic antioxidants. Each BHT consumes two peroxy radicals.Burton, G. W.; Ingold, K. U., "Autoxidation of biological molecules. 1. Antioxidant activity of vitamin E and related chain-breaking phenolic antioxidants in vitro", Journal of the American Chemical Society, 1981, volume 103, pp 6472 – 6477.

Applications

BHT is listed under three categories in catalogues and databases, such as food additive, household product ingredient, industrial additive, personal care product/cosmetic ingredient, pesticide ingredient, plastic/Rubber ingredient and Medical/Veterinary/Research.US Dept of Health & Human Services. Household Products Database. http://hpd.nlm.nih.gov/.US EPA. InertFinder. linkhttp://iaspub.epa.gov/apex/pesticides/f?p=175:1:. US National Library of Medicine. Haz-Map. linkhttp://hazmap.nlm.nih.gov/index.php. US National Library of Medicine. Hazardous Substances Data Bank. linkhttp://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?HSDB.

Food additive

BHT is primarily used as an antioxidant food additive. In the United States, it is classified as generally recognized as safe (GRAS) based on a National Cancer Institute study from 1979 in rats and mice. Bioassay of Butylated Hydroxytoluene (BHT) for Possible Carcinogenicity, National Cancer Institute, CARCINOGENESIS Technical Report Series No. 150, 1979, 128 pp National Institutes of Health It is approved for use in the U.S. by the Food and Drug Administration: For example, 21 CFR § 137.350(a)(4) allows BHT up to 0.0033% by weight in "enriched rice", while 9 CFR § 381.147(f)(1) allows up to 0.01% in poultry "by fat content". It is permitted in the European Union under E321. European Food Safety Authority|url = http://www.efsa.europa.eu/en/efsajournal/pub/2588|website = www.efsa.europa.eu|accessdate = 2015-10-04}} It is forbidden as food additive in Japan (since 1958), Romania, Sweden, and Australia. Since the 1970s, BHT has been steadily replaced with butylated hydroxyanisole (BHA). Some food companies have voluntarily eliminated BHT from their products. Others like General Mills and Kellogg's announced in February 2015, following a petition by Vani Hari, that they were going to phase it out.

Antioxidant

BHT is also used as an antioxidant in products such as cosmetics, pharmaceuticals, rubber, electrical transformer oil (at 0.35%), Ficha de Datos de Seguridad, Transformador 64, benco.com, page 1, retrieved December 29, 2008, (español). and embalming fluid. In the petroleum industry, where BHT is known as the fuel additive AO-29, it is used in hydraulic fluids, turbine and gear oils, and jet fuels.Michael Ash, Irene Ash, Handbook of Preservatives, Synapse Information Resources, 2004. . BHT is also used to prevent peroxide formation in diethyl ether and other laboratory chemicals. Some additive products contain BHT as their primary ingredient, while others contain the chemical merely as a component of their formulation, sometimes alongside butylated hydroxyanisole (BHA).

Derivatives

Derivatives include Tazofelone, Terbuficin, Darbufelone, Prifelone, Tebufelone and BSPP.

Health effects

Debate surrounds the link of BHT to cancer risk, asthma, and behavioral issues in children;{{cite report | author = | year = 1986 | title = Butylated hydroxytoluene (BHT) | url = https://monographs.iarc.fr/ENG/Monographs/vol1-42/mono40.pdf | archiveurl = https://web.archive.org/web/20150905203436/http://monographs.iarc.fr/ENG/Monographs/vol1-42/mono40.pdf | archivedate = 2015-09-05 | dead-url = no | publisher = World Health Organization: International Agency For Research On Cancer | format = PDF | volume = 40 | pages = 161–206 }} some studies show a potential to increase and some showing a decreased risk.Kensler TW, Egner PA, Trush MA, Bueding E, Groopman JD, "Modification of aflatoxin B1 binding to DNA in vivo in rats fed phenolic antioxidants, ethoxyquin and a dithiothione", Carcinogenesis, 1985;6(5):759-63.Williams GM, Iatropoulos MJ, "Inhibition of the hepatocarcinogenicity of aflatoxin B1 in rats by low levels of the phenolic antioxidants butylated hydroxyanisole and butylated hydroxytoluene", Cancer Lett. 1996;104(1):49-53.Franklin RA, "Butylated hydroxytoluene in sarcoma-prone dogs", Lancet. 1976;1(7972):1296. There is in vitro indication for endocrine disruption with effect on the testes and thyroid. Because of this uncertainty, the consumer group Center for Science in the Public Interest recommend to avoid BHT and puts BHT in its "caution" column. The National Cancer Institute determined in 1979 that it was noncarcinogenic in a mouse model. BHT is marketed as a health food supplement in capsule form. It has been reported to have anti-viral effects, particularly in use against herpes family viruses, sometimes in combination with L- lysine and vitamin C.Snipes W, Person S, Keith A, Cupp J, "Butylated hydroxytoluene inactivates lipid-containing viruses", Science. 1975;188(4183):64-6.Brugh M Jr, "Butylated hydroxytoluene protects chickens exposed to Newcastle disease virus. Science", 1977;197(4310):1291-2.Richards JT, Katz ME, Kern ER, "Topical butylated hydroxytoluene treatment of genital herpes simplex virus infections of guinea pigs", Antiviral Res. 1985;5(5):281-90.Kim KS, Moon HM, Sapienza V, Carp RI, Pullarkat R, "Inactivation of cytomegalovirus and Semliki Forest virus by butylated hydroxytoluene", J Infect Dis. 1978;138(1):91-4.Pirtle EC, Sacks JM, Nachman RJ, "Antiviral effectiveness of butylated hydroxytoluene against pseudorabies (Aujeszky’s disease) virus in cell culture, mice, and swine", Am J Vet Res. 1986;47(9):1892-5.Chetverikova LK, Ki’ldivatov II, Inozemtseva LI, Kramskaia TA, Filippov VK, et al. "Factors of antiviral resistance in the pathogenesis of influenza in mice", Vestn Akad Med Nauk SSSR. 1989;(11):63-8. RussianChetverikova LK, Inozemtseva LI, "Role of lipid peroxidation in the pathogenesis of influenza and search for antiviral protective agents" Vestn Ross Akad Med Nauk. 1996;(3):37-40. Russian This latter use has made it into some of the more popular literature.Pearson D, Shaw S, "Life Extension: A Practical Scientific Approach", New York, NY: Warner Books, Inc.; 1982:206-207. Closely related phenol antioxidants exhibit low toxicity. For example, the of 2,6-di-tert-butylphenol is greater than 9 g/kg.

References

External links

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This article based upon the http://en.wikipedia.org/wiki/Butylated_hydroxytoluene, the free encyclopaedia Wikipedia and is licensed under the GNU Free Documentation License.
Further informations available on the list of authors and history: http://en.wikipedia.org/w/index.php?title=Butylated_hydroxytoluene&action=history
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