Butylated hydroxytoluene

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Butylated hydroxytoluene
Butylated hydroxytoluene BHT structure.png
Chemical structure of BHT
Names
IUPAC name
2,6-Di-tert-butyl-4-methylphenol
Other names
2,6-Di-tert-butyl-p-cresol
3,5-(Dimethylethyl)-4-hydroxytoluene
3,5-Di-tert-butyl-4-hydroxytoluene
4-Methyl-2,6-di-tert-butyl phenol
Additin RC 7110
AO-29
Avox BHT
BHT
DBPC
Dibutylated hydroxytoluene
E321
Properties
C15H24O
Molar mass 220.356 g/mol
Appearance White to yellow powder
Odor Phenolic, aromatic
Density 1.048 g/cm3
Melting point 70 °C (158 °F; 343 K)
Boiling point 265 °C (509 °F; 538 K)
1.1 mg/L (20 °C)
Solubility Soluble in acetone, benzene, cyclohexane, ethanol, heptane, hexane,isopropanol, methanol, methyl cellosolve, methyl ethyl ketone, petroleum ether, toluene, vegetable oil
Insoluble in propylene glycol
Vapor pressure 0.01 mmHg (20°C)
Thermochemistry
-400 kJ/mol
Hazards
Safety data sheet Sigma-Aldrich
Flash point 127 °C (261 °F; 400 K)
Lethal dose or concentration (LD, LC):
2,000 mg/kg (rat, dermal)
Related compounds
Related compounds
Phenol
Butylated hydroxyanisole
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Butylated hydroxytoluene (BHT), also known as dibutylhydroxytoluene, is an organic compound, chemically a derivative of phenol, widely for its antioxidant properties, such as preservative for many reagents and other products.

Properties

Chemical

BHT acts as a synthetic structural analog 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. Each BHT consumes two peroxy radicals.[1]

Physical

BHT is a white to yellowish crystalline solid insoluble in water, with a phenolic odor.

Availability

BHT is sold by chemical suppliers.

Phytoplankton, including the green algae Botryococcus braunii, as well as three different cyanobacteria (Cylindrospermopsis raciborskii, Microcystis aeruginosa and Oscillatoria sp.) are capable of producing minute amounts of BHT.

Preparation

Industrially, BHT is prepared by the reaction of p-cresol (4-methylphenol) with isobutylene (2-methylpropene), catalyzed by conc. sulfuric acid:

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

Projects

  • Antioxidant
  • Reagent preservative

Handling

Safety

BHT is considered to posses low toxicity.

Storage

BHT should be kept in air-tight containers.

Disposal

No special disposal is required. Should be strongly diluted and poured down the drain.

References

  1. https://pubs.acs.org/doi/10.1021/ja00411a035

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