PURPOSE: To produce the titled substance useful as an antioxidant, by reacting an alkylphenol compound with oxygen using inexpensive methanol as a solvent, cupric halide, etc. as a catalyst and the halide of alkali metal, etc. as an accelerator.

CONSTITUTION: A quinone compound is produced by reacting an alkylphenol compound free from substituent group at the p-position based on the hydroxyl group with oxygen under an oxygen partial pressure of 2W100atm. in methanol solvent, using cupric halide and an alkali metal or alkaline earth metal hydrooxide as a catalyst and an alkali metal or alkaline earth metal halide as an accelerator, at -10W+80°C. The copper used as the catalyst can be recovered easily to enable the repeated use of the catalyst. The recovery can be carried out by removing methanol from the reaction mixture after the completion of the reaction, extracting the residue with an organic solvent and an aqueous solution of hydrochloric acid, separating the extract into two layers, and recovering the accelerator and copper from each layer.