PURPOSE: An alkylphenol which is unsubstituted in the para position to the hydroxyl group is oxidized in the presence of a catalyst of a combination of a specific copper compound and an amine under a relatively low oxygen pressure to produce the titled compound in high yield.
CONSTITUTION: The oxidation of an alkylphenol which is unsubstituted in the para position to the hydroxyl group is carried out in a solvent such as acetonitrile or methyl ethyl ketone in the presence of a catalyst of a combination of a cupric halide with a tertiary amine, using an oxygen-containing gas to produce a quinone. The reaction is preferably conducted under 2W100atm pressure and vigorous stirring is needed during the reaction. The tertiary amine as a partner of the copper compound is preferably e.g. triethylamine or tri-n-butylamine and its amount is 0.1W10 times, preferably 1W3 times the molar amount of the cupric halide.