Photochlorination of aniline in Fe3+-containing saline water under simulated solar light irradiation

Photochlorination of aniline was observed in aqueous solutions containing dissolved Fe-III and chloride ions under simulated solar light irradiation. Effects of O-2, Cl-, Fe3+ and pH on the formation of chloroanilines (CAs) were investigated. para-chloroaniline (4CA) was identified as the main chlorinated product. The formation of 4CA is enhanced with increased concentrations of Cl- or Fe3+, and decreased pH, whereas oxygen plays a negligible role in the process. The results indicate that, Cl-center dot is formed mainly by the photodissociation of FeCl2+-FeCl2+ complexes, and reacts with Cl- to produce Cl-2(center dot-). Aniline is then oxidised by Cl-2(center dot-) into an anilino radical cation, which further reacts with Cl-2(center dot-) to generate CAs. The photochlorination of aniline in natural seawater was also observed. Other phototransformation products of aniline were detected and a transformation pathway was proposed. This work provides evidence for the photochemical chlorination path of aniline-based aromatic amines in aqueous solutions.