Photodegradation of 1,5-dihydroxynaphthalene catalyzed by meso-tetra(4-sulfonatophenyl)porphyrin in aerated aqueous solution

The photodegradation of 1,5-dihydroxynaphthalene catalyzed by meso-tetra(4-sulfonatophenyl)porphyrin (H2TPPS4−) under visible light irradiation in aerated aqueous solution has been studied and the main product has been identified as 5-hydroxy-1,4-naphthoquinone. It is found that the photodegradation is dependent on the pH of reaction system and the addition of sodium azide (NaN3) leads to a significant decrease in the degree of 1,5-dihydroxynaphthalene photodegradation. The species distribution of H2TPPS4− in solution was obtained from potentiometric titration experiments. It is suggested that the mono-protonated monomeric species [H(H2TPPS)]3− is the main active species of H2TPPS4− to catalyze 1,5-dihydroxynaphthalene photodegradation.

The photodegradation of 1,5-dihydroxynaphthalene catalyzed by meso-tetra(4-sulfonatophenyl)porphyrin (H2TPPS4−) under visible light irradiation in aerated aqueous solution has been studied. Considering the dependence of the photodegradation to the pH and the species distribution of H2TPPS4− in solution, it is suggested that the mono-protonated monomeric species [H(H2TPPS)]3− is the main active species of H2TPPS4− to catalyze photodegradation of 1,5-dihydroxynaphthalene.Figure optionsDownload as PowerPoint slide