2,4-Dimethyl-6-tert-butylphenol is the organic compound with the formula Me2(tert-Bu)C6H2OH (Me = methyl, tert-Bu = tertiary butyl). It is a colorless oil that is classified as an alkylated phenol.
It is used as an antioxidant, e.g. to prevent gumming in fuels, and as an ultraviolet stabilizer. It is used in jet fuels, gasolines, and avgas.
It is prepared by alkylation of xylenol with isobutylene. This alkylation provides a means to separate 2,4-xylenol from 2,5-xylenol since 2,4-dimethyl-6-tert-butylphenol is insoluble in 10% NaOH but 2,5-dimethyl-6-tert-butylphenol is soluble. Subsequent to separation, the tert-butyl group can be removed in strong acid.
One of its trade names is Topanol A. It is found in antioxidant mixtures AO-30, AO-31, AO-32, IONOL K72, IONOL K78, IONOL K98, and others.