Titania photocatalysts for selective oxidations in water

Abstract

Heterogeneous photocatalysis by polycrystalline semiconductor oxides is an unconventional technology that has been mainly applied for the degradation of organic and inorganic pollutants in both the vapor and liquid phase. The application of photocatalysis in synthetic routes has also been researched in recent years, demonstrating its viability as an alternative route in organic chemistry. This work illustrates the main findings in the application of heterogeneous photocatalysis to the oxidation of organic compounds dissolved in water, free of any organic co-solvent. Two main aspects of the oxidative process have been studied: the first one is the partial oxidation of various mono-substituted aromatic compounds, investigated to better understand the influence of the substituent group on the reactivity of these species and on the distribution of oxidized products. The second aspect investigated is the possibility of using heterogeneous photocatalysis for the selective oxidation of alcohols to aldehydes and ketones. The partial oxidation of alcohols to produce carbonyl compounds is of great industrial importance; generally, it is performed in environmentally harmful organic solvents at high temperatures and pressures by using stoichiometric oxygen donors that not only are expensive and toxic, but also produce large amounts of dangerous waste