Phenol oxidation with hydrogen peroxide into catechol (CL) and hydroquinone (HQ) over H-MFI, H-MOR, H-USY and H-BEA in the presence of diethylketone was investigated. Among the examined zeolites, large pore zeolites having 12-membered oxygen ring aperture, H-MOR, H-USY and H-BEA, showed higher reaction yield than that having 10-membered oxygen ring aperture, H-MFI. The reaction yield over these zeolites was in the order of H-BEA > H-USY > H-MOR > H-MFI, thus the superior one was H-BEA in this work. The sum of the reaction yield of CL and HQ based on hydrogen peroxide was >89% over H-BEA (SiO2/Al2O3 = 150) in the presence of diethylketone at 373 K for 5 min reaction. (C) 2003 Elsevier B.V. All rights reserved.