Fe2O3-photocatalysis with sunlight and UV light: Oxidation of aniline

Fe2O3 photocatalyzes the oxidation of aniline to azobenzene and exhibits sustainable catalytic activity. The reaction in ethanol was studied with natural sunlight and UV irradiation (365 nm) as a function of [aniline], catalyst loading, airflow rate, solvent composition, etc. The product formation is larger with illumination at 254 nm than at 365 nm. Electron donors enhance the photocatalysis and singlet oxygen quencher fails to inhibit the catalysis. The photocatalysis occurs in protic and aprotic solvents. The mechanism of photocatalysis is discussed and the product formation analyzed using a kinetic model.