Rose Bengal solution singlet oxygen generation, photosensitization

The dye Rose-Bengal, in solution or as a suspension, is a very suitable sensitizer for generating singlet oxygen (Foote, 1%8 Kearns, 1971). There are several limitations to the dyes as photosensitizers (a) When the sensitizer is used in a solution, solvents which can be used for the reaction are limited, (b) The dye bleaches if longer reaction times are used, (c) The dye can sometimes react with the reactants or with the products, (d) Separation of the products from the dye in the reaction mixture is often difficult. 

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