Photooxidation of 4-chlorophenol sensitised by iron meso-tetrakis(2,6-dichloro-3-sulfophenyl)porphyrin in aqueous solution

• Autor(a) principal: Silva, Eliana
• Data de Publicação: 2003
• Outros Autores: Pereira, Mariette M., Burrows, Hugh D., Azenha, M. E., Sarakha, Mohamed, Bolte, Michèle
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10316/10726; https://doi.org/10.1039/b308975d

The photosensitised degradation of 4-chlorophenol (4-CP) by iron meso-tetrakis(2,6-dichloro-3-sulfophenyl)porphyrin (FeTDCPPS) has been studied in aerated aqueous solution, and is shown to lead to formation of p-benzoquinone (BQ) and p-hydroquinone (HQ) as main photoproducts. In deaerated solution no p-benzoquinone was formed. The photolysis products were identified by high performance liquid chromatography (HPLC) and UV-visible spectroscopy. The photodegradation in aerated solution was also carried out in the presence of sodium azide (NaN3) as a singlet oxygen [1O2(1g)] quencher, and showed a significant decrease in the rate of photolysis, suggesting under these conditions, that Type II sensitisation is one of the dominant mechanisms of 4-CP degradation. Support for this comes from laser flash photolysis and time-resolved singlet oxygen phosphorescence measurements. However, these also show direct reaction between the excited porphyrin and 4-CP, indicating that there are two mechanisms involved in the chlorophenol photodegradation.