Y-Ba-Cu-O mixed oxides for production of diphenols in liquid-solid phase

Superconductor mixed oxides were often used as catalysts at higher temperature in gas phase oxidations, and considered not suitable for lower temperature reactions in the liquid-solid phase; here the catalysis of YBa₂Cu₃O_7±x and Y₂BaCuO_5±x, in the phenol hydroxylation at lower temperature with H₂O₂ as oxygen donor was studied, and found that the superconductor YBa₂Cu₃O_7±x has no catalytic activity for phenol hydroxylation, but Y₂BaCuO_5±x does, even has better catalytic activity and stability than most previously reported ones. With the studies of catalysis of other simple metal oxides and perovskite-like mixed oxides, a radical substitution mechanism is proposed and the experimental facts are explained clearly, and draw a conclusion that the perovskite-like mixed oxides with (AO)(ABO₃) and (AO)₂(ABO₃) structure have better catalytic activity than the simple perovskite oxides with (ABO₃)₃ structure alone, and (AO) structure unit is the key for the mixed oxides to have the phenol hydroxylation activity. No pollution of this process is very important for its further industrial application.