Inhibition of the Humic Substances-Sensitized Photo-Oxygenation of Furfurylic Alcohol by 2,4,6-Trimethylphenol

摘要

The capacity of humic substances extracted from soil and water to generate singlet oxygen (~1O2) upon irradiation was demonstrated for long. Singlet oxygen is produced by energy transfer from triplet excited states derived from humic substances to ground state oxygen. Humic substances sensitized -degradation of organic compounds bearing labile hydrogen atoms such as phenols was also reported. The nature of the oxidant species abstracting the electron or the H atom from the chemical is not yet firmly known : oxidant triplet excited states and oxygenated radicals have been proposed. To discriminate between these two possibilities we have studied the influence of 2,4,6-trimethylphenol on the humic substances-sensitized photo-oxygenation of furfurylic alcohol. A drastic inhibiting effect was found demonstrating that reactive species that degrade 2,4,6-trimethylphenol are also those that generate singlet oxygen.