OXIDATION CHARACTERISTICS OF ALIPHATIC ACIDS USING DIFFERENTLY 'DOPED' TIN OXIDE ANODES

摘要

The anodic oxidation of valeric acid has been studied using Sb 'doped' tin oxide, Sn(Sb)-oxide, anodes prepared by thermal decomposition. The oxidation products resulting from the anodic oxidation of valeric acid have been identified showing that this acid is effectively oxidized to mainly CO_2 using Sn(Sb)-oxide anodes. Oxalic acid was found to be formed as a major solution product/intermediate during the electrolysis, while octane (> 1 ppm) was not found to be formed. The oxidation of valeric acid using OH~(dot) generated by the decomposition of H_2O_2 by UV light resulted in the same solution products as found for the anodic oxidation using Sn(Sb) anodes. The anodic oxidation characteristics for oxalic acid using differently doped (Sb, Cl~-, F~-) tin oxides were also investigated and showed that this acid is oxidized using any of these oxide anodes. Differences for the oxidation rate of valeric acid, as well as in the stability of the oxide anodes, were observed even for Sn(Sb)-oxide anodes prepared under the same conditions but at different times. This appears to be related to different Sb/Sn ratios of the individual prepared oxide anodes and indicates just how difficult it is to achieve a high level of reproducibility in the formation of the catalytic coating.