PURPOSE: To prepare the titled compound useful as an intermediate of pharmaceuticals and agricultural chemicals, in high conversion, with little side reactions, by oxidizing an arylalkylmethane with an oxygen-containing gas in the presence of an aqueous solution of a caustic alkali and a polymer of lower aldehyde.

CONSTITUTION: An α-aryl tertiary alcohol of formula II is prepared by introducing an oxygen-containing gas into a reaction system containing an aryldialkylmethane of formula I (X is H, halogen such as Cl, Br, etc., alkyl such as methyl, ethyl, etc., or alkoxy such as methoxy, ethoxy, etc.; R1 and R2 are alkyl such as methyl, ethyl, propyl, etc.; n is 1W3) in the presence of an aqueous solution of a caustic alkali (e.g. aqueous solution of NaOH, KOH, etc.). The above reaction is carried out in the presence of a polymer of a lower aldehyde (e.g. paraldehyde, metaldehyde, trioxymethylene, etc.) in the reaction system. The reaction temperature is ≥80°C, preferably 90W130°C. The reaction proceeds in high efficiency, and the post-treatment of the product can be carried out safely.