Supported photosensitizers for the visible light activation of phenols towards oxygen

To circumvent the drawbacks of the homogeneous photosensitization, a series of photosensitizing molecules, mainly porphyrins and phthalocyanines, were supported on aminopropyl silica and/or exchange resins. Their grafting ratios were evaluated and their efficiencies were assayed on the ability to photo-oxidize phenol under 900 W/m2 visible light. A comparison was done by determining the time necessary to obtain 50% consumption of the substrate. Under these conditions, the meso tetra(4-sulfonatophenyl)porphine displayed the best photocatalytic effect.