Synthesis, Characterization and Catalytic Properties of Series of Water-soluble Sulfonated Porphyrins

A series of water. soluble sulfonated porphyrins with different substituents and substituted positions has been efficiently synthesized by modifying the traditional sulfonation route, and has been characterized by H-1 NMR, Fourier transform infrared spectroscopy(FTIR), ultraviolet-visible spectroscopy(UV-Vis) and mass spectrscopy(MS). These porphyrins were used as photocatalysts for the oxidation of 1,5-dihydroxynaphthalene using H2O2 as oxidant. The product was 5-hydroxy-1,4-naphthoquinone with conversion rates ranging from 78% to 95%. The effects of the position of the sulfonic group on the phenyl ring, the number of substituents, the electron and steric hindrance of the substituent groups on the catalytic activities of the porphyrins have been investigated and the results indicate that all these factors can affect the catalytic activities. The catalytic mechanism has been discussed and the kinetic data show that the catalytic process is a first-order reaction.