Butylated hydroxytoluene
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225269006
2008-07-12T20:15:13Z
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Date the maintenance tags or general fixes
{{Chembox new
| Name = Butylated hydroxytoluene
| ImageFile = 2,6-bis(1,1-dimethylethyl)-4-methylphenol.svg
| ImageSize = 200px
| ImageName = Butylated hydroxytoluene
| IUPACName = 2,6-bis(1,1-dimethylethyl)-4-methylphenol
| OtherNames = 2,6-di-''tert''-butyl-4-methylphenol; 2,6-di-''tert''-butyl-''p''-cresol (DBPC); butylated hydroxytoluene; BHT
| Section1 = {{Chembox Identifiers
| CASNo = 128-37-0
| EINECS = 204-881-4
| RTECS = GO7875000
}}
| Section2 = {{Chembox Properties
| Formula = C<sub>15</sub>H<sub>24</sub>O
| MolarMass = 220.35 g/mol
| Appearance = white powder
| Density = 1.048 g/cm³, solid
| Solubility = insol.
| MeltingPt = 70-73 °C
| BoilingPt = 265 °C (538.15 K)
| pKa =
}}
| Section7 = {{Chembox Hazards
| ExternalMSDS = [http://ptcl.chem.ox.ac.uk/MSDS/DI/2,6-di-t-butyl-p-cresol.html External MSDS]
| MainHazards = Flammable
| FlashPt = 127 °C
| RPhrases = 22-36 37 38
| SPhrases = 26-36
}}
| Section8 = {{Chembox Related
| OtherCpds = [[butylated hydroxyanisole]]
}}
}}
'''Butylated hydroxytoluene''' (BHT), also known as '''Butylhydroxytoluene''', is a [[lipophilic]] (fat-soluble) [[organic compound]] that is primarily used as an [[antioxidant]] [[food additive]] ([[E number]] E321) as well as in [[cosmetics]], pharmaceuticals, [[jet fuel]]s, [[rubber]], [[petroleum]] products, and [[embalming]] fluid.
==Chemistry==
BHT is produced by [[alkylation]] reaction of [[cresol|''p''-cresol]] with [[isobutylene]]. The species behaves as a synthetic analogue 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:
:RO<sub>2</sub><sup>.</sup> + ArOH → ROOH + ArO<sup>.</sup>
:RO<sub>2</sub><sup>.</sup> + ArO<sup>.</sup> → nonradical products
where R is alkyl or aryl, and where ArOH is BHT or related phenolic antioxidants. One can see that each BHT consumes two peroxy radicals.<ref>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. DOI: 10.1021/ja00411a035</ref>
In the chemical industry it is added to [[tetrahydrofuran]] and [[diethyl ether]] in order to inhibit the formation of dangerous [[organic peroxide]]s.
==Controversy==
Concerns have been raised about the use of BHT in food products.{{Fact|date=September 2007}} The compound has been banned for use in food in [[Japan]] ([[1958]]), [[Romania]], [[Sweden]], and [[Australia]]. The US has barred it from infant foods.{{Fact|date=September 2007}} Some food industries have voluntarily eliminated it from their products. However, BHT is also marketed as a health food supplement in capsule form. In different studies, BHT has been
reported to cure some cancers, but to encourage others.{{Fact|date=April 2008}} BHT is well studied because of
public concern over synthetic preservatives. BHT was largely removed from food in the 1970s,
to be replaced with the less well studied [[Butylated hydroxyanisole|BHA]].
==References==
<references/>
==See also==
*[[Butylated hydroxyanisole]] (BHA)
==External links==
* [http://bht-coldsores.blogspot.com An experiment on the effectiveness BHT has against herpes & cold sore outbreaks]
* [http://chemistry.about.com/library/weekly/aa082101a.htm Why are BHA and BHT in foods? Are they safe?]
*[http://ntp.niehs.nih.gov/index.cfm?objectid=070510F7-946E-0334-8C3427E3D9734FD0 Bioassay of BHT, includes structure]
*[http://www.inchem.org/documents/icsc/icsc/eics0841.htm BUTYLATED HYDROXYTOLUENE (ICSC)]
*[http://www.shadetreephysics.com/bht.htm Butylated Hydroxytoluene (BHT) Antioxidant]
[[Category:Antioxidants]]
[[Category:Phenols]]
[[Category:Fuel antioxidants]]
[[Category:Food antioxidants]]
[[de:Butylhydroxytoluol]]
[[es:BHT]]
[[fr:Hydroxytoluène butylé]]
[[it:Butilidrossitoluene]]
[[hu:Butil-hidroxi-toluol]]
[[nl:Butylhydroxytolueen]]
[[ja:ジブチルヒドロキシトルエン]]
[[pl:Butylowany hydroksytoluen]]
[[pt:BHT]]
[[ru:Ионол]]
[[zh:2,6-二叔丁基對甲酚]]