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| Names | |
|---|---|
| Preferred IUPAC name 2-tert-Butyl-4-methoxyphenol and 3-tert-butyl-4-methoxyphenol (mixture) | |
Other names
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| Identifiers | |
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3D model (JSmol) | |
| ChEBI | |
| ChEMBL | |
| ChemSpider |
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| ECHA InfoCard | 100.042.315 |
| E number | E320(antioxidants, ...) |
| UNII |
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| Properties | |
| C11H16O2 | |
| Molar mass | 180.247 g/mol |
| Appearance | Waxy solid |
| Density | 1.0587 g/cm3 at 20 °C |
| Melting point | 48 to 55 °C (118 to 131 °F; 321 to 328 K) |
| Boiling point | 264 to 270 °C (507 to 518 °F; 537 to 543 K) |
| Insoluble in water | |
| Solubility | Freely soluble inethanol,methanol,propylene glycol; soluble in fats and oils |
Refractive index (nD) | 1.5303 at 589.3 nm[2] |
| Related compounds | |
Related compounds | Butylated hydroxytoluene |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Butylated hydroxyanisole (BHA) is a synthetic, waxy, solidpetrochemical. Itsantioxidant properties have caused it to be widely used as a preservative in food, food packaging, animal feed, cosmetics, pharmaceuticals, rubber, and petroleum products.[3] BHA has been used in food since around 1947.[4]
BHA consists of a mixture of twoisomeric organic compounds, 2-tert-butyl-4-hydroxyanisole and 3-tert-butyl-4-hydroxyanisole. It is prepared from4-methoxyphenol andisobutylene.
The conjugated aromatic ring of BHA is able to stabilizefree radicals, sequestering them. By acting as free radicalscavengers, further free radical reactions are prevented.
Since 1947, BHA has been added to edible fats and fat-containing foods for its antioxidant properties as it preventsrancidification of food which creates objectionable odors.[5] It has been assigned theE number E320. It is often combined with a similar chemical,butylated hydroxytoluene (BHT).[4]
The U.S.National Institutes of Health report that BHA is reasonably anticipated to be a humancarcinogen based on evidence of carcinogenicity in experimental animals. In particular, when administered in high doses as part of their diet, BHA causespapillomas andsquamous cell carcinomas of the forestomach in rats and Syrian goldenhamsters.[6] In mice, there is no carcinogenic effect;[6] in fact, there is evidence of a protective effect against the carcinogenicity of other chemicals.[5]
When examining humanpopulation statistics, the usual low intake levels of BHA show no significant association with an increased risk of cancer.[7]
The European Commission has conducted an evaluation of literature. They noted the lack of potential for the compound to induce carcinogenic effects in humans; studies showing carcinogenic effects in hamsters are not relevant to humans (which lack a forestomach). Also noted is that endocrine disruption, if any, is only likely to be present at levels vastly exceeding the intake as a food.[8]
TheInternational Agency for Research on Cancer (IARC) – Summaries & Evaluations stated butylated hydroxyanisole was tested for carcinogenicity in two experiments in rats and in two experiments in hamsters by administration in the diet, inducing benign and malignant tumours of the forestomach.[9]
One of its metabolites isTBHQ (t-butylhydroquinone), a preservative made infamous by food writerMichael Pollan.[4]
