Abstract:
The absorbance maxima of the reduction products for the heteropoly compound potassium 1:12 dodecatungstosilicate seventeen hydrate, K4 [SiW12O40] • 17H2O, with isopropyl alcohol and sulfuric acid have been studied using a Bausch and Lomb Spectronic 20 photometer, and GCA McPherson ultraviolet-visible spectrophotometer. The position of absorbance maxima and maximum absorbance depend on the concentrations of the heteropoly compound and isopropyl alcohol, irradiation time and deaerated mixtures with nitrogen. The rate of photooxidation of organic substrates and related compounds with the heteropoly compound occurring in an ultraviolet photochemical reactor was studied and reported. The rate of photooxidation of alcohols and amine with the heteropoly compound is secondary > primary = amine > tertiary. Amino acids, except glycine, and saccharides such as glucose, maltose, and sucrose, also are photooxidized by the heteropoly compound. The rate of the photooxidation of saccharides is glucose> sucrose > maltose. The proposed reactive functional
group in the photooxidation of the alcohols and amine is either a -CH(OH) or a -CH(NH) moiety. The proposed mechanism for the photocatalyzed oxidation of alcohol by the heteropoly anion is consistent with these results.
