Cu precipitate formed during the benzene oxidation catalyzed by supported Cu in the presence of ascorbic acid and O2

The Cu precipitate formed during the liquid-phase oxidation of benzene to phenol with supported Cu catalyst in the presence of O2 and ascorbic acid was confirmed to be a Cu oxalate analogue (Cu1+[OC(O)C(O)OH]1−), of which Cu1+ species were thought to be the cause of the deactivation of the benzene oxidation.