| tert-Butylhydroquinone | |
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2-(1,1-Dimethylethyl)-1,4-benzenediol |
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Other names
TBHQ(i) |
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| Identifiers | |
| CAS number | 1948-33-0 |
| PubChem | 16043 |
| ChemSpider | 15235 |
| DrugBank | DB07726 |
| ChEMBL | CHEMBL242080 |
| Jmol-3D images | Image 1 |
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| Properties | |
| Molecular formula | C10H14O2 |
| Molar mass | 166.22 g mol−1 |
| Appearance | Tan powder |
| Density | 1.050 g/mL |
| Melting point |
127-129 °C, 400-402 K, 261-264 °F |
| Boiling point |
273 °C, 546 K, 523 °F |
| Solubility in water | Slightly Soluble |
| Acidity (pKa) | 10.80±0.18 |
| Hazards | |
| MSDS | External MSDS |
| R-phrases | R22 |
| S-phrases | S26 S27 S28 |
| Main hazards | Harmful |
| Flash point | 171 °C |
| Related compounds | |
| Related compounds | Butylated hydroxyanisole (BHA) 4-tert-Butylcatechol (TBC) |
| (verify) (what is: /?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
tert-Butylhydroquinone (TBHQ, tertiary butylhydroquinone) is an aromatic organic compound which is a type of phenol. It is a derivative of hydroquinone, substituted with tert-butyl group.
TBHQ is a highly effective antioxidant.[1] In foods, it is used as a preservative for unsaturated vegetable oils and many edible animal fats.[2] 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.[1] It can be combined with other preservatives such as butylated hydroxyanisole (BHA). As a food additive, its E number is E319. It is added to a wide range of foods, with the highest limit (1000 mg/kg) permitted for frozen fish and fish products. Its primary advantage is enhancing storage life.
It is used industrially as a stabilizer to inhibit autopolymerization of organic peroxides. It is also used as a corrosion inhibitor in biodiesel.[3] In perfumery, it is used as a fixative to lower the evaporation rate and improve stability. It is also added to varnishes, lacquers, resins, and oil field additives.
Both the European Food Safety Authority (EFSA) and the United States Food and Drug Administration (FDA) have evaluated TBHQ and determined that it is safe to consume at the concentration allowed in foods.[4] The FDA sets an upper limit of 0.02% of the oil or fat content in foods.[5] At higher doses, it has some negative health effects on lab animals, such as producing precursors to stomach tumors and damage to DNA.[6] A number of studies have shown that prolonged exposure to high doses of TBHQ may be carcinogenic,[7] especially for stomach tumors.[8] 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).[9] The EFSA considers TBHQ to be non-carcinogenic.[4] A review of scientific literature concerning the toxicity of TBHQ determined that there is a wide margin of safety between the levels of intake by humans and the doses that produce adverse effects in animal studies.[10] However, it should also be noted that the review cited in the last sentence took place some time ago (1986).