2,6-Di-tert-butylphenol is an organic compound with the structural formula 2,6-((CH3)3C)2C6H3OH. This colorless solid alkylated phenol and its derivatives are used industrially as UV stabilizers and antioxidants for hydrocarbon-based products ranging from petrochemicals to plastics.[1] Illustrative of its usefulness, it prevents gumming in aviation fuels.
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| Preferred IUPAC name
2,6-Di-tert-butylphenol | |
| Other names
2,6-Bis(1,1-dimethylethyl)phenol
Dibutylphenol 2,6-Bis(tert-butyl)phenol 2,6-Di(1,1-dimethylethyl)phenol 2,6-DTBP Ethanox 701 Ethyl 701 Ethyl AN 701 Irganox L 140 Isonox 103 TK 12891 | |
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| ECHA InfoCard | 100.004.441 |
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| UNII | |
| UN number | 2430, 3077 |
CompTox Dashboard (EPA)
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| Properties | |
| C14H22O | |
| Molar mass | 206.329 g·mol−1 |
| Appearance | Low-melting colourless solid |
| Melting point | 34 to 37 °C (93 to 99 °F; 307 to 310 K) |
| Boiling point | 253 °C (487 °F; 526 K) |
| Hazards | |
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| Warning | |
| H315, H319, H410 | |
| P264, P273, P280, P302+P352, P305+P351+P338, P321, P332+P313, P337+P313, P362, P391, P501 | |
| Flash point | 118 °C (244 °F; 391 K) |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Production
edit2,6-Di-tert-butylphenol is prepared industrially via the Friedel–Crafts alkylation of phenol with isobutene catalyzed by aluminium phenoxide:
- C6H5OH + 2 CH2=C(CH3)2 → ((CH3)3C)2C6H3OH
In this way, approximately 2.5M kg/y are produced.[2] Alkylation of phenol usually favours the para-position, and a strong lewis acid such as the Al3+ ion is necessary to give selective ortho‑alkylation.[3][4] If a conventional brønsted acid is used then 2,4-di-tert-butylphenol will be produced instead.
Applications
editIts dominant use is as an antioxidant.
2,6-di-tert-butylphenol is a precursor to more complex compounds used as antioxidants and light-protection agents for the stabilization for polymers. Of particular note is methyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate (CAS# 6386-38-5), which is formed by the Michael addition of methyl acrylate. This compound is used as a feedstock in the synthesis of more complex antioxidants such as Irganox 1098. 2,6-Di-tert-butylphenol is also used in the synthesis of CGP-7930, probucol, and nicanartine.
Safety and regulation
editThe LD50 is 9200 mg/kg, indicating a low toxicity.[2]
2,6-Di-tert-butylphenol is covered by the U.S. Department of Transportation Code of Federal Regulations 49 CFR 172.101, Appendix B (20 Dec 2004). This substance is designated by the U.S. Department of Transportation (DOT) as a marine pollutant.
See also
editReferences
edit- ^ Peter P. Klemchuk (2005). "Antioxidants". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a03_091. ISBN 978-3527306732.
- ^ a b Helmut Fiege; Heinz-Werner Voges; Toshikazu Hamamoto; Sumio Umemura; Tadao Iwata; Hisaya Miki; Yasuhiro Fujita; Hans-Josef Buysch; Dorothea Garbe; Wilfried Paulus (2002). "Phenol Derivatives". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a19_313. ISBN 978-3527306732.
- ^ Kolka, Alfred J.; Napolitano, John P.; Filbey, Allen H.; Ecke, George G. (June 1957). "The ortho-Alkylation of Phenols 1". The Journal of Organic Chemistry. 22 (6): 642–646. doi:10.1021/jo01357a014.
- ^ Küpper, Friedrich-Wilhelm (June 2004). "A new mechanism — key for an improved synthesis of 2,6-di-tert-butylphenol". Applied Catalysis A: General. 264 (2): 253–262. doi:10.1016/j.apcata.2003.12.043.