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DOI

Reaction of the carbonate radical with substituted anilines

01 Jan 1984-Vol. 93, Iss: 1, pp 47-52
TL;DR: In this article, the rate constants for the reaction of carbonate radical with aniline and some parasubstituted anilines were determined by the flash photolysis technique.
Abstract: Rate constants for the reaction of carbonate radical with aniline and some parasubstituted anilines have been determined by the flash photolysis technique. Using σ+ para values the rate constants at pH 8.5 correlate very well with the Hammett equation yielding ρ= − 1. The carbonate radical oxidises aniline giving the anilino radical. The products so formed have been identified through studies under conditions of continuous irradiation.
Citations
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Journal ArticleDOI
TL;DR: Results demonstrate that UVA-TiO(2) photocatalysis can be a very effective approach for degrading sulfonamide micropollutants, particularly in natural waters exhibiting either alkaline pH or low concentrations of NOM, or both conditions.

357 citations

Journal ArticleDOI
TL;DR: The triplet state of oxcarbazepine (3OXC∗) was found to play an important role in OXC degradation via UV and UV/H2O2, and hydroxyl radicals (•OH) and singlet oxygen (1O2) were found to be the dominant ROS in OxC degradation.

107 citations

Journal ArticleDOI
TL;DR: This review summarizes many of the reported QSARs for aquatic oxidations of organic compounds with emphasis on the interrelation between traditional empirical models and the potential for future development of QSars based on theoretical models.
Abstract: Even in the absence of microbiological mediation, oxidation is one of the most important chemical processes contributing to the degradation of organic contaminants in the aquatic environment. The oxidants that are responsible for these reactions include hydroxyl radical, carbonate radical, organic oxyl and peroxyl radicals, peroxides, excited triplet states of organic chromophores, singlet molecular oxygen, ozone, chlorine dioxide, permanganate, and chromate. Some of these oxidants contribute to natural attenuation of organic contaminants, but many are of greater interest because of their role in engineered remediation technologies. Kinetic studies of these processes have lead to numerous quantitative structure-activity relationships (QSARs). Many of these QSARs are simple empirical correlations to common convenient descriptor variables like Hammett constants (sigma), half-wave oxidation potentials (E1/2), energies of the highest occupied molecular orbital (E(HOMO)) or rate constants for other oxidation reactions. However, several environmentally relevant, aqueous-phase oxidation reactions have been described with QSARs based on theoretical models for electron transfer that were developed by Marcus-Hush and Rehm-Weller. This review summarizes many of the reported QSARs for aquatic oxidations of organic compounds with emphasis on the interrelation between traditional empirical models and the potential for future development of QSARs based on theoretical models.

102 citations


Additional excerpts

  • ...Similarly, data on p-substituted anilines [82] (neglecting the 2COO(2) substituent), yielded:...

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Journal ArticleDOI
TL;DR: A good linear relationship is observed between the natural logarithms of kCO3•- and the negative values of the Hammett Σσp+ constant for aromatic PPCPs, indicating that electron-donating groups promote the attack of benzene derivatives by CO3•-.

98 citations

Journal ArticleDOI
TL;DR: In this article, a competition between a chemical of known reactivity and a compound with unknown reactivity toward carbonate radical was set up, and the second-order rate constants for substituted anilines corresponded to reference values with a relative error less than 10%.
Abstract: The carbonate radical is produced from the scavenging of the hydroxyl radical by carbonate/bicarbonate and is strongly electrophilic toward electron-rich compounds such as aromatic amine and sulfur-containing compounds. Carbonate radical reactivity (CO3⋅−) was measured by setting up a competition between a chemical of known reactivity and a compound with unknown reactivity toward CO3⋅−. The carbonate radical was produced using a novel method whereby KOONO (potassium peroxonitrite) was dissolved into 0.01 NaHCO3 solution initially producing a HO⋅, which was rapidly scavenged by HCO3⋅−, yielding CO3⋅− CO3⋅− production was monitored using a stopped-flow spectrometer at the absorption band for CO3⋅− of 600 nm. Results using this competition kinetic method indicated the second-order rate constants for substituted anilines corresponded to reference values with a relative error less than 10%. Using σpara+ values, the rate constants of substituted anilines at pH 9.0 correlated well (R2 = 0.98) with the Hammett equation yielding ρ = −0.89. To measure the reactivity of pesticides toward the carbonate radical, p-nitroaniline (PNA) was selected as the standard competitor. Of the nine pesticides tested, fenthion was the most reactive, followed by phorate, with rate constants above 107/M/s. Fluometuron and atrazine were of intermediate reactivity, and methyl parathion was one of the least reactive.

92 citations


Cites background or methods from "Reaction of the carbonate radical w..."

  • ...0 when using spara(1) values [13], the same r value as observed for the reaction of the carbonate radical...

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  • ...Thus, it is likely the rate constants are influenced by the ionization potential of the amine, suggesting possible electron transfer from aniline to the carbonate radical [13]....

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References
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BookDOI
01 Jan 1972
TL;DR: In this article, the Hammett Equation and the present position were separated by the use of Linear Free Energy Relationships (LFE) and Optical Spectroscopy (OS).
Abstract: 1 The Hammett Equation-the Present Position.- 2 The Separation of Polar, Steric, and Resonance Effects by the Use of Linear Free Energy Relationships.- 3 Linear Free Energy Relationships and Optical Spectroscopy.- 4 Linear Correlations of Substituent Effects in 1H, 19F, and 13C Nuclear Magnetic Resonance Spectroscopy.- 5 The Influence of the Solvent on Organic Reactivity.- 6 The Influence of the Reagent on Organic Reactivity.- 7 Linear Free Energy Relationships in Inorganic Chemistry.- 8 Linear Free Energy Relationships in Enzymology.- 9 The Interpretation of Drug Action through Linear Free Energy Relationships.- 10 Interpretation of Mass Spectrometry Data through Linear Free Energy Relationships.- Author Index.

490 citations