Cobalt, manganese, and iron in cationic positions of the secondary structure of Mo- or W-Keggin type heteropolyanions were investigated in the liquid-phase oxidation of phenol in glycerol. Iron tungstophosphate series is the most active in this reaction, yielding catechol and hydroquinone. On the other hand, manganese and cobalt salts of heteropolyacids demonstrate higher catalytic activity in the degradation of phenol to CO2 in comparison with iron tungstophosphates. It is the first time that glycerol is used as alternative "green" solvent in phenol oxidation reaction. (C) 2015 Elsevier B.V. All rights reserved.