Partial or complete heterogeneous photocatalytic oxidation of neat toluene and 4-picoline in liquid organic oxygenated dispersions containing pure or iron-doped titania photocatalysts

Abstract

The heterogeneous photocatalytic oxidation of neat toluene and 4-picoline in liquid organic oxygenated dispersions containing pure or iron-doped titania photocatalysts has been studied in a photochemical reactor radiating predominantly at 365–366 nm. The investigation correlates experimental conditions such as structural aspects, surface properties, concentration and chemical nature of the photocatalysts, and illumination times, with chemical yields and selectivity of products. For toluene, the main photocatalytic products found were benzaldehyde, benzyl alcohol and benzoic acid. In particular, our results show that traces of water present in the reaction system play an important role in the distribution of products. Likewise, the important role of the adsorption effects in photocatalysis based on semiconductors is emphasized. Thus, differences in the affinity and mode of the adsorption of different molecules (i.e., toluene, picolines) should give rise to differences in the distribution of the reaction products.