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This paper presents ferrate(VI) (FeVIO42-, FeVI) oxidation of a wide range of sulfonamide antibiotics (SAs) containing five- and six-membered heterocyclic moieties (R) in their molecular structures. Kinetics measurements of the reactions between FeVI and SAs at different pH (6.5 – 10.0) give species-specific second-order rate constants, k5 and k6 of the reactions of protonated FeVI (HFeO4-) and unprotonated FeVI (FeVIO42-) with protonated SAs (HX), respectively. The values of k5 varied from (1.2 ± 0.1) × 103 to (2.2 ± 0.2) × 104 M-1 s-1, while the range of k6 was from (1.1 ± 0.1) × 102 to (1.0 ± 0.1) × 103 M-1 s-1 for different SAs. The transformation products of reaction between FeVI and sulfadiazine (SDZ, contains a six-membered R) include SO2 extrusion oxidized products (OPs) and aniline hydroxylated products. Comparatively, oxidation of sulfisoxazole (SIZ, a five-membered R) by FeVI has OPs that have no SO2 extrusion in their structures. Density functional theory (DFT) calculations are performed to demonstrate SO2 extrusion in oxidation of SDZ by FeVI. The detailed mechanisms of oxidation are proposed to describe the differences in the oxidation of six- and five-membered heterocyclic moieties (R) containing SAs (i.e., SDZ versus SIZ) by FeVI.
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Gas-Phase Organic Oxidation Chemistry and Atmospheric Particles
Organic aerosols comprise a rich mixture of compounds, many generated via nonselective radical oxidation. This produces a plethora of products, most unidentified, and mechanistic understanding has improved with instrumentation. Recent advances include recognition that some peroxy radicals undergo internal H-atom transfer reactions to produce highly oxygenated molecules and recognition that gas-phase association reactions can form higher molecular weight products capable of nucleation under atmospheric conditions. Particles also range from molecular clusters near 1 nm diameter containing a few molecules to coarse particles above 1 μm containing 1 billion or more molecules. A mixture of organics often drives growth of particles. We can describe this via detailed thermodynamics, and we can also describe the physics driving mixing between separate populations containing semi-volatile organics. Finally, fully size-resolved particle microphysics enables detailed comparisons between theory and observations in chamber experiments.
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- PAR ID:
- 10210320
- Editor(s):
- Barker, John R; Steiner, Allison L
- Date Published:
- Journal Name:
- Advances in atmospheric chemistry
- Volume:
- 2
- ISSN:
- 2425-0015
- Page Range / eLocation ID:
- 199-317
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1142/9789813271838_0004
