Journal ArticleDOI
Transformation kinetics of phenols in water: photosensitization by dissolved natural organic material and aromatic ketones.
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TLDR
The results show that reactive excited triplet states are important photooxidants in natural waters and should be considered for assessing the abiotic degradation of chemicals.Abstract:
Different dissolved natural organic materials photosensitize the transformation of a series of methyl and methoxy phenols at pH 8 with a very similar high selectivity (reactivity range 50). This selectivity falls in the range of that achieved using the aromatic ketones benzophenone (BP), 3'-methoxyacetophenone (3'-MAP), and 2-acetonaphthone (2-AN) as model photosensitizers. For both natural and model sensitizers, the photooxidation at pH 8 is not controlled by singlet oxygen. Deuterium isotope effects (k H /k D ) of different phenols are 0.7-1.3 for humic and fulvic acids and 1.1-1.7 for BP, suggesting an electron transfer mechanism. In contrast, the isotope effect for 2-AN of 4 indicates an H-atom abstraction reaction. The results show that reactive excited triplet states are important photooxidants in natural waters and should be considered for assessing the abiotic degradation of chemicals. The reactive triplet state concentration is estimated to be 10 -14 M in the top meter of Lake Greifensee under summer noon sunlight, and this leads to a half-life of 7 h for 2,4,6-trimethylphenol. Further still uncharacterized photooxidants derived from the dissolved organic material are also involved in the phototransformation of the phenols.read more
Citations
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Journal ArticleDOI
Geometrical Effects on the Intramolecular Quenching of π,π* Aromatic Ketones by Phenols and Indoles
Julia Pérez-Prieto,Salah-Eddine Stiriba,Francisco Bosca,Agustín Lahoz,Luis R. Domingo,Fouad Mourabit,and Sandra Monti,Miguel A. Miranda +7 more
TL;DR: In this article, a series of bichromophoric compounds 1−12 containing the 2-benzoylthiophene (BT) and phenol (PhOH) or indole (InH) moieties has been used to determine the possible geometrical effects in the intramolecular quenching of triplet excited ketones, resulting in formal hydrogen abstraction.
Journal ArticleDOI
Impacts of Polar Changes on the UV-induced Mineralization of Terrigenous Dissolved Organic Matter.
TL;DR: Open questions, in addition to those shown in the Graphical Abstract, remain regarding the resulting contributions of tDOM photomineralization to CO2 production and global warming.
Journal ArticleDOI
Aqueous-Phase Secondary Organic Aerosol Formation Via Reactions with Organic Triplet Excited States—a Short Review
Hui Chen,Xinlei Ge,Zhaolian Ye +2 more
TL;DR: In this paper, a short review summarizes current studies regarding the secondary organic aerosol formed in atmospheric aqueous phases (cloud/fog drops and aerosols) via oxidation by the organic triplet excited states, including the current systems of interests, and major findings.
Journal ArticleDOI
OH-Initiated Oxidation of Imidazoles in Tropospheric Aqueous-Phase Chemistry.
TL;DR: The radical-driven aqueous-phase oxidative degradation reactions of the hydroxyl radical (·OH) with imidazoles were investigated and temperature and pH dependencies of the reactions as well as the activation parameters have been determined and discussed.
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