PURPOSE: To obtain a compound useful as a raw material for producing polyether useful as a functional high polymer, by catalytically oxidizing bis(hydroxyaryl)alkane and a carboxylic acid anhydride under a specific condition in a liquid phase.

CONSTITUTION: A bis(hydroxyaryl)alkane and a carboxylic acid anhydride are catalytically oxidized in a corresponding carboxylic acid solvent by the use of a carbonyl compound as an oxidation promoter in the presence of a metallic compound catalyst (e.g. cobalt salt) of group 8 of the periodic table in a liquid phase. The reaction is carried out at 90W180°C under 1W50kgf/cm2 pressure for 0.1W20hr to give the aimed substance. Acetaldehyde, methyl ethyl ketone, peracetic acid, etc., may be cited as the oxidation promoter and the amount of the promoter used is 0.5W10mol based on 1mol bis(hydroxyaryl)alkane. 4,4- Dihydroxydiphenylmethane may be cited as the bis(hydroxyaryl)alkane of the starting substance.