2,6-Di-tert-butylphenol (2,6-DTBP) serves as the starting material in the production of the most efficient phenolic antioxidants known today and also for the synthesis of 4,4′-dihydroxybiphenyl. The compound is usually synthesised by the alkylation of phenol or of 2-tert-butylphenol (2-TBP) with isobutene. In the presence of aluminium tris-(phenolate) catalyst temperatures between 100 and 125 °C and at pressures up to 25 bar have been employed[1].
Widely used as antioxidant in fuels, lubricants and polymers. Employed as a synthetic intermediate for the production of higher molecular weight phenolic antioxidants. Used as an oxidation inhibitor and stabilizer (e.g. for fuel, oil and gasoline) and also used in plastics and rubber. Also applied as an intermediate and an antioxidant in aviation gasoline.
Antioxidant Intermediate, Pharmaceuticals
Antioxidant for Gasoline, Jet Fuels, and Electrical Insulating Oils
ChEBI: 2,6-di-tert-butylphenol is a member of the class of phenols carrying two tert-butyl substituents at positions 2 and 6. It has a role as an antioxidant. It is a member of phenols and an alkylbenzene.
Odorless colorless to light yellow solid or liquid. Floats on water. Freezing point is 97°F.
Phenols, such as 2,6-Di-tert-butylphenol, do not behave as organic alcohols, as one might guess from the presence of a hydroxyl (-OH) group in their structure. Instead, they react as weak organic acids. Phenols and cresols are much weaker as acids than common carboxylic acids (phenol has Ka = 1.3 x 10^[-10]). These materials are incompatible with strong reducing substances such as hydrides, nitrides, alkali metals, and sulfides. Flammable gas (H2) is often generated, and the heat of the reaction may ignite the gas. Heat is also generated by the acid-base reaction between phenols and bases. Such heating may initiate polymerization of the organic compound. Phenols are sulfonated very readily (for example, by concentrated sulfuric acid at room temperature). The reactions generate heat. Phenols are also nitrated very rapidly, even by dilute nitric acid.
Irritates eyes and (on prolonged contact) skin. Ingestion causes irritation of mouth and stomach.
Flammability and Explosibility
Non flammable
2,6-Di-tert-butylphenol is synthesized by the alkylation of phenol or 2-tert-butylphenol with isobutene[2]. An improved process involves the alkylation of 2-tert-butylphenol with isobutene in the presence of tris(2-tert-butylphenolate)aluminium under low temperature and low pressure conditions[2].
Crystallise the phenol from aqueous EtOH or n-hexane. [Beilstein 6 III 2061.]
[1] Küpper, Friedrich-Wilhelm. “A new mechanism — key for an improved synthesis of 2,6-di-tert-butylphenol.” Applied Catalysis A: General 264 2 (2004): Pages 253-262.
[2]Küpper, F.-W. (2004). A new mechanism--key for an improved synthesis of 2,6-di-tert-butylphenol. Applied Catalysis A: General, 264(2), 253–262.
https://doi.org/10.1016/j.apcata.2003.12.043
