butylated hydroxytoluene

Butylated hydroxytoluene
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 Y
EC number	204-881-4
RTECS number	GO7875000
SMILES	CC(C)(C)c1cc(C)cc(c1O)C(C)(C)C
InChI	1/C15H24O/c1-10-8-11(14(2,3)4)13(16)12(9-10)15(5,6)7/h8-9,16H,1-7H3
InChI key	NLZUEZXRPGMBCV-UHFFFAOYAU
ChemSpider ID	13835296
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 K)
Solubility in water	insol.
Hazards
MSDS	External MSDS
R-phrases	22-36 37 38
S-phrases	26-36
Flash point	127 °C
Related compounds
Related compounds	Butylated hydroxyanisole
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

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 an antioxidant additive in cosmetics, pharmaceuticals, jet fuels, rubber, petroleum products, electrical transformer oil^[1], and embalming fluid.

Production

BHT is prepared by the reaction of p-cresol (4-methylphenol) with isobutylene (2-methylpropene) catalysed by sulfuric acid: ^[2]

CH₃(C₆H₄)OH + 2 CH₂=C(CH₃)₂ → ((CH₃)₃C)₂CH₃C₆H₂OH

Alternatively, BHT is prepared from 2,6-di-tert-butylphenol by hydroxymethylation or aminomethylation followed by hydrogenolysis. Approximately 4M kg/y are produced.

Reactions

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.^[3]

Controversy

In the 1970s, Benjamin Feingold, a San Francisco MD who established the Feingold Diet claimed that BHT could produce hyperactivity in some children. In addition, some controversy surrounds the link of BHT to cancer risk,^[4] some studies showing the potential to increase and some showing a decrease in risk.^[5][6][7] Some food industries have voluntarily eliminated this additive from their products, and since the 1970s it has been steadily replaced with the less studied BHA.

BHT is marketed as a health food supplement in capsule form. It has been reported to have anti-viral effects, particularly in use against herpes family viruses and in combination with L-lysine and Vitamin C.^{[8][9][10][11][12][13][14]} This latter use has made it into some of the more popular literature.^[15][16]

Closely related phenol antioxidants exhibit low toxicity. For 2,6-di-tert-butylphenol, the LD50 is greater than 9 g/kg.^[2]

References

1. ^ Ficha de Datos de Seguridad, Transformador 64, page 1, retrieved December 29, 2008, (español).
2. ^ ^{a b} Helmut Fiege, Heinz-Werner Voges, Toshikazu Hamamoto, Sumio Umemura, Tadao Iwata, Hisaya Miki, Yasuhiro Fujita, Hans-Josef Buysch, Dorothea Garbe, Wilfried Paulus "Phenol Derivatives" Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2002. doi:10.1002/14356007.a19_313 Article Online Posting Date: June 15, 2000.
3. ^ 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
4. ^ "Butylated hydroxytoluene (BHT)", IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, 1986;40:161-206.
5. ^ Kensler TW, Egner PA, Trush MA, Bueding E, Groopman JD, "Modification of aflatoxin B1 binding to DNA in vivo in rats fed phenolic antioxidants, ethoxyquin and a dithiothione", Carcinogenesis, 1985;6(5):759-63.
6. ^ Williams GM, Iatropoulos MJ, "Inhibition of the hepatocarcinogenicity of aflatoxin B1 in rats by low levels of the phenolic antioxidants butylated hydroxyanisole and butylated hydroxytoluene", Cancer Lett. 1996;104(1):49-53.
7. ^ Franklin RA, "Butylated hydroxytoluene in sarcoma-prone dogs", Lancet. 1976;1(7972):1296.
8. ^ Snipes W, Person S, Keith A, Cupp J, "Butylated hydroxytoluene inactivates lipid-containing viruses", Science. 1975;188(4183):64-6.
9. ^ Brugh M Jr, "Butylated hydroxytoluene protects chickens exposed to Newcastle disease virus. Science", 1977;197(4310):1291-2.
10. ^ Richards JT, Katz ME, Kern ER, "Topical butylated hydroxytoluene treatment of genital herpes simplex virus infections of guinea pigs", Antiviral Res. 1985;5(5):281-90.
11. ^ Kim KS, Moon HM, Sapienza V, Carp RI, Pullarkat R, "Inactivation of cytomegalovirus and Semliki Forest virus by butylated hydroxytoluene", J Infect Dis. 1978;138(1):91-4.
12. ^ Pirtle EC, Sacks JM, Nachman RJ, "Antiviral effectiveness of butylated hydroxytoluene against pseudorabies (Aujeszky’s disease) virus in cell culture, mice, and swine", Am J Vet Res. 1986;47(9):1892-5.
13. ^ Chetverikova LK, Ki’ldivatov II, Inozemtseva LI, Kramskaia TA, Filippov VK, et al. "Factors of antiviral resistance in the pathogenesis of influenza in mice", Vestn Akad Med Nauk SSSR. 1989;(11):63-8. [in Russian]
14. ^ Chetverikova LK, Inozemtseva LI, "Role of lipid peroxidation in the pathogenesis of influenza and search for antiviral protective agents" Vestn Ross Akad Med Nauk. 1996;(3):37-40. [in Russian]
15. ^ Pearson D, Shaw S, "Life Extension: A Practical Scientific Approach", New York, NY: Warner Books, Inc.; 1982:206-207.
16. ^ Mann JA, Fowkes SW, "Wipe Out Herpes with BHT", Manhattan Beach, Calif: MegaHealth Society; 1983.

See also

• Butylated hydroxyanisole (BHA)

External links

• An experiment on the effectiveness BHT has against herpes & cold sore outbreaks
• Why are BHA and BHT in foods? Are they safe?
• Bioassay of BHT, includes structure
• BUTYLATED HYDROXYTOLUENE (ICSC)
• Butylated Hydroxytoluene (BHT) Antioxidant