The anodic oxidation of p-benzoquinone and maleic acid

The oxidation of organics, in particular of p-benzoquinone and maleic acid, at high anodic potentials has been studied using a range of anode material s such as noble-metal-based oxides and antimony-doped tin oxides. The influ ence of the current density was also investigated showing that the oxidatio n rate of p-benzoquinone increased only slightly with increasing current de nsity. The efficiency of the p-benzoquinone oxidation was found to depend o n several properties of the anode material, not just its chemical nature. F urthermore, efficiencies for the partial oxidation of p-benzoquinone using specially prepared noble-metal-oxide-based anodes were found to be only som ewhat smaller or even as high as those observed for PbO2 or antimony-doped tin oxide anodes, respectively. The anodic electrolysis of maleic acid solu tions was found to decrease the activity of IrO2 for the oxidation of organ ic compounds. This was not observed when PbO2 was employed for the oxidatio n of maleic acid. (C) 1999 The Electrochemical Society. S0013-4651(98)12-09 9-2. All rights reserved.