Mechanism of Chlorine Dioxide and Chlorate Ion Formation from the Reaction of Hypobromous Acid and Chlorite Ion

Furman, Christopher S.; Margerum, Dale W.

doi:10.1021/ic980262q

Cited by 99 publications

(145 citation statements)

References 41 publications

(51 reference statements)

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“…11 This reaction has been thoroughly studied and found to be subject to general acid catalysis. 30 We used the experimentally determined rate constant, 11 1.55 × 10 4 M -1 s -1 , to start our fitting procedure.…”

Section: Discussionmentioning

confidence: 99%

Kinetics and Mechanism of the Decomposition of Chlorous Acid

et al. 2003

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The kinetics of decomposition of aqueous chlorous acid has been reinvestigated at pH 0.7-1.9, ionic strength 1.0 M (HSO 4 -/SO 4 2-), and temperature 25.0 ( 0.1°C. Optical absorbances were collected in the 240-450 nm wavelength range for up to ∼90% decomposition for time series lasting as long as 2 days. The number of absorbing species was investigated by matrix rank analysis; no absorbing intermediate was formed in significant concentration during the decomposition. Of the many mechanistic models tested, the one that fit best included the following reactive intermediates: HOCl, explains the variation in stoichiometric ratio as well as the maximum observed in the initial rate of ClO 2 formation as a function of pH. The kinetics of chlorous acid decomposition cannot be quantitatively fit through the last stages of the reaction without postulating a first-order decomposition. Scission of chlorous acid to give short-lived hydroxyl and chlorine-(II) monoxide is a plausible route for this process. A set of best-fit and literature-derived parameters is presented for the complete mechanism.

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Section: Discussionmentioning

confidence: 99%

Kinetics and Mechanism of the Decomposition of Chlorous Acid

et al. 2003

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“…S12, SI). The four other detected transformation products (19)(20)(21)(22) had all a mass higher than IPN, suggesting the potential formation of coupling products. None of them could be identified but, according to its mass and retention time, product 19 could possibly be a hydroxylated IPN (Fig.…”

Section: Transformation Products Formed In the Laccase-abts-ipn Systemmentioning

confidence: 99%

“…A stock solution of aqueous chlorine (OCl − , 8.16 mM) was prepared by diluting a sodium hypochlorite solution (around 5%, Sigma) 100 times. The final OCl − concentration was measured at pH 10.9 by spectrophotometry at 292 nm (extinction coefficient 292 nm of 362 M −1 cm −1 ) [20].…”

Section: Chemicals and Enzymementioning

confidence: 99%

Sulfamethoxazole and isoproturon degradation and detoxification by a laccase-mediator system: Influence of treatment conditions and mechanistic aspects

Margot

Copin

Gunten

et al. 2015

Biochemical Engineering Journal

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a b s t r a c tThe potential of laccase-mediator systems (LMS) for the removal and detoxification of two wastewater micropollutants, the antibiotic sulfamethoxazole (SMX) and the herbicide isoproturon (IPN), was assessed. The influence of various parameters on micropollutant oxidation rates, such as pH, mediator, enzyme and pollutant concentrations, was investigated with three mediators: 2,2 -azinobis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS), syringaldehyde (SA) and acetosyringone (AS). Both pollutants were completely transformed within a few hours in presence of laccase and ABTS, as well as, for SMX, in presence of AS or SA. The three mediators were consumed during the reaction (no catalytic reactions observed), at a ratio mediator/pollutant between 1.1 and 16 mol/mol. Faster oxidation kinetics were observed at lower pH values, but also higher mediator/pollutant ratios were required. Several transformation products were formed, including cross-coupled products. Product mixtures were always less toxic to algae than untreated pollutants. Finally, a kinetic model that could explain the experimental observations was established. Based on the findings in this study LMS appears to be a promising option to treat concentrated and potentially toxic industrial effluents.

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“…The stock solutions were diluted to the desired concentration, and the pH was adjusted to the target pH with dilute aqueous HCl. ) (8) were determined spectrophotometrically with an Agilent 8453 UV-visible spectrophotometer (Agilent Technologies Deutschland GmbH, Waldbronn, Germany). The stability of NVC-422 at room temperature over a period of 430 days was monitored spectrophotometrically at its max value.…”

Section: Methodsmentioning

confidence: 99%

Chemical Characterization and Biological Properties of NVC-422, a Novel, Stable N -Chlorotaurine Analog

Wang

Belisle

Bassiri

et al. 2011

Antimicrob Agents Chemother

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During oxidative burst, neutrophils selectively generate HOCl to destroy invading microbial pathogens. Excess HOCl reacts with taurine, a semi-essential amino acid, resulting in the formation of the longer-lived biogenerated broad-spectrum antimicrobial agent, N-chlorotaurine (NCT). In the presence of an excess of HOCl or under moderately acidic conditions, NCT can be further chlorinated, or it can disproportionate to produce N,N-dichlorotaurine (NNDCT). In the present study, 2,2-dimethyltaurine was used to prepare a more stable N-chlorotaurine, namely, N,N-dichloro-2,2-dimethyltaurine (NVC-422). In addition, we report on the chemical characterization, in vitro antimicrobial properties, and cytotoxicity of this compound. NVC-422 was shown effectively to kill all 17 microbial strains tested, including antibiotic-resistant Staphylococcus aureus and Enterococcus faecium. The minimum bactericidal concentration of NVC-422 against Gram-negative and Grampositive bacteria ranged from 0.12 to 4 g/ml. The minimum fungicidal concentrations against Candida albicans and Candida glabrata were 32 and 16 g/ml, respectively. NVC-422 has an in vitro cytotoxicity (50% cytotoxicity ‫؍‬ 1,440 g/ml) similar to that of NNDCT. Moreover, our data showed that this agent possesses rapid, pH-dependent antimicrobial activity. At pH 4, NVC-422 completely killed both Escherichia coli and S. aureus within 5 min at a concentration of 32 g/ml. Finally, the effect of NVC-422 in the treatment of an E. coli-infected granulating wound rat model was evaluated. Treatment of the infected granulating wound with NVC-422 resulted in significant reduction of the bacterial tissue burden and faster wound healing compared to a saline-treated control. These findings suggest that NVC-422 could have potential application as a topical antimicrobial.As part of the innate immune system, leukocytes are capable of generating and releasing reactive oxygen species. During oxidative burst, neutrophils selectively generate hypochlorous acid to destroy invading microbial pathogens. In a secondary reaction, hypochlorous acid reacts with taurine, a semi-essential amino acid. The resulting N-chlorotaurine (NCT) is a wellknown antimicrobial and anti-inflammatory oxidant (12, 15). Furthermore, NCT has shown significant bactericidal and fungicidal properties with relatively low toxicity compared to other oxidants (13,14). In the presence of an excess of hypochlorous acid or under moderately acidic conditions, NCT can be further chlorinated or, alternatively, it can disproportionate to form N,N-dichlorotaurine (NNDCT), which also has broadspectrum antimicrobial activity (9). Unfortunately, both NCT and NNDCT have relatively short solution half-lives, decomposing by hydrolytic dehydrochlorination (5, 6, 16). Because of this instability, the potential usefulness of the endogenous Nchlorotaurines as marketable therapeutics is limited. Replacement of the hydrogens at the ␤-carbon of taurine by methyl groups prevents the dehydrochlorination process, thereby circumventing this instabi...

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Mechanism of Chlorine Dioxide and Chlorate Ion Formation from the Reaction of Hypobromous Acid and Chlorite Ion

Cited by 99 publications

References 41 publications

Kinetics and Mechanism of the Decomposition of Chlorous Acid

Kinetics and Mechanism of the Decomposition of Chlorous Acid

Sulfamethoxazole and isoproturon degradation and detoxification by a laccase-mediator system: Influence of treatment conditions and mechanistic aspects

Chemical Characterization and Biological Properties of NVC-422, a Novel, Stable N -Chlorotaurine Analog

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