Butylated hydroxytoluene
From Wikipedia, the free encyclopedia
| Butylated hydroxytoluene | |
|---|---|
 |
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| IUPAC name | 2,6-bis(1,1-dimethylethyl)-4-methylphenol |
| Other names | 2,6-di-tert-butyl-4-methylphenol; 2,6-di-tert-butyl-p-cresol (DBPC); butylated hydroxytoluene; BHT |
| Identifiers | |
| CAS number | [128-37-0] |
| EINECS number | |
| RTECS number | GO7875000 |
| Properties | |
| Molecular formula | C15H24O |
| Molar mass | 220.35 g/mol |
| Appearance | white powder |
| Density | 1.048 g/cm³, solid |
| Melting point |
70-73 °C |
| Boiling point |
265 °C (538.15 K) |
| Solubility in water | insol. |
| Hazards | |
| MSDS | External MSDS |
| Main hazards | Flammable |
| R-phrases | 22-36 37 38 |
| S-phrases | 26-36 |
| Flash point | 127 °C |
| Related compounds | |
| Related compounds | butylated hydroxyanisole |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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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 fuels, rubber, petroleum products, and embalming fluid.
Contents |
[edit] Chemistry
BHT is produced by alkylation reaction of 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:
- RO2. + ArOH → ROOH + ArO.
- RO2. + ArO. → 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.[1]
In the chemical industry it is added to tetrahydrofuran and diethyl ether in order to inhibit the formation of dangerous organic peroxides.
[edit] Controversy
Concerns have been raised about the use of BHT in food products.[citation needed] The compound has been banned for use in food in Japan (1958), Romania, Sweden, and Australia. The US has barred it from infant foods.[citation needed] 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.[citation needed] 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 BHA.
[edit] References
- ^ 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
[edit] See also
- Butylated hydroxyanisole (BHA)
