Reduction electrochimique du nitrobenzene, en milieu micellaire aqueux, a divers pH. Influence de la nature des tensio-actifs

Pouillen, P.; Martre, Anne-Marie; Martinet, Pierre

doi:10.1016/0013-4686(82)80207-7

Cited by 20 publications

(11 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The assumption has been proven to be likely because the morphology of the PNBD polarograms does not change when SDS micelles are present in the medium. The assumption is also consistent with results of other electroactive molecules in surfactant systems. ,,, A second supposition involved is that the PNBD probe does not change the micelle size and shape. This approach seems valid provided that the probe concentration is kept much smaller that the surfactant concentration and the surfactant concentrations employed are low enough so that micellar growth to rods can be neglected .…”

Section: Discussionsupporting

confidence: 85%

“…Redox reactions of micelle-solubilized organic compounds have been an object of study for more than three decades by employing electrochemical techniques, and a number of reviews on the topic are available. − Two major lines of research appear evident: first, examination of micellar effects on half-wave potentials, − rate constants, − diffusion coefficients, − and so forth of well-known redox couples, and second, studies concerned with the stability of the electrogenerated anion or cation radicals. ,− Meyer et al have reported the remarkable stabilization of the electrogenerated anion radical of phthalonitrile in the presence of cationic micelles examined the role of anionic, cationic, and nonionic micellar systems on the heterogeneous one-electron-transfer process of nitrobenzene, NB, to yield the anion radical NB •- , and on the stability of NB •- .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effects of Sodium Dodecyl Sulfate, SDS, Micelles on the Electrochemical Behavior of a Model Arenediazonium Ion. 2. Estimation of the Association Constant of the Electrochemically Generated Aryl Radicals with SDS Micelles

2002

View full text Add to dashboard Cite

The effects of sodium dodecyl sulfate, SDS, on the reductive electrochemistry of p-nitrobenzenediazonium tetrafluoroborate, PNBD, were investigated at two different pHs by employing differential pulse polarography (DPP). At pH ) 2, the reduction peaks of the -N2 + and -NO2 groups are completely overlapped. Upon addition of SDS ([SDS] < critical micelle concentration, cmc), their peak potentials, Ep, are shifted in opposite directions, Ep(-N2 + ) toward more anodic values and Ep(-NO2) toward more cathodic values, and two polarographic peaks are clearly observed, suggesting that PNBD interacts with the sulfate group of SDS leading to the formation of an ion-pair. At the same pH but at [SDS] > cmc, the peak potentials shift in the reverse directions as those below the cmc and the polarographic peaks overlap again, an effect that is interpreted in terms of the incorporation of PNBD to the SDS micellar aggregates. At pH ) 5, the reduction peaks of the -N 2 + and -NO2 are clearly separated. Addition of SDS shifts their peak potentials in opposite directions, the same as those at pH ) 2, up to a maximum (-N2 + ) or minimum (-NO2) at [SDS] ) cmc, after which the directions are reversed getting a constant value. Peak currents, ip, for either -N2 + and -NO2 decrease smoothly reaching a plateau region. Quantitative analyses of the effects of SDS on Ep and on ip at [SDS] > cmc allowed estimations of the association constants of the parent PNBD and of the electrochemically generated aryl radical, Ar • , with SDS micelles. The association constant of the aryl radical is higher than that of PNBD by a factor of ∼2, indicating that the nitrobenzene radicals are preferentially stabilized in SDS micelles. The results obtained, together with those in previous work, suggest that the combination of DPP with arenediazonium ions as probe molecules provides a rapid, easy, and low-cost method to estimate the stability constants of a large number of aryl radicals to biomimetic systems, information that may be valuable for understanding relevant redox reactions in the more complex biological systems.

show abstract

Section: Discussionsupporting

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Effects of Sodium Dodecyl Sulfate, SDS, Micelles on the Electrochemical Behavior of a Model Arenediazonium Ion. 2. Estimation of the Association Constant of the Electrochemically Generated Aryl Radicals with SDS Micelles

2002

View full text Add to dashboard Cite

show abstract

“…The assumption is likely because the morphology of the BD polarograms does not change in the absence or presence of SDS micelles. The assumption is also consistent with results of other electroactive molecules in surfactant systems …”

Section: Resultssupporting

confidence: 91%

“…The assumption is also consistent with results of other electroactive molecules in surfactant systems. [35][36][37][38] A third important assumption is related to how BD distributes in the micelles and its effect on the effective probe concentration at the surface of the electrode. Literature reports indicate that the distribution of substrates in micelles is not uniform but is of the Poisson type.…”

Section: Effects Of Sds Micelles On the Electrochemical Behavior Of Bdmentioning

confidence: 99%

Partitioning of aryl radicals in micellar systems

Sienkiewicz

Losada‐Barreiro

Bravo‐Díaz

2018

J of Physical Organic Chem

View full text Add to dashboard Cite

Determining the association constants of radicals to biomimetic systems is not a simple task because of the inherent experimental difficulties associated to their “in‐situ” generation together with their high chemical instability, requiring the use of radical trapping agents in combination with, for example, magnetic (eg, EPR) and/or time‐resolved techniques (eg, frequency comb spectroscopy) to indentify and quantify them. Here, we have exploited the unique electrochemical properties of arenediazonium ions, ArN2+, to estimate the association constant of the electrochemically generated aryl radicals derived from benzenediazonium ions, BD, with sodium dodecyl sulfate (SDS) micelles. When ArN2+ are reduced on an Hg electrode, they acquire an electron yielding the corresponding arenediazenyl radical, ArN2•, which undergoes further decomposition to produce the aryl radical, Ar•. BD partitions between the aqueous and micellar pseudophases, and, upon increasing [SDS], peak currents decrease and the peak potentials are shifted. Results indicate that the association constant of the aryl radical to SDS micelles is 3 times higher than that of the parent substrate as a consequence of its higher hydrophobicity compared with that of the parent molecule. The method is feasible because of the large number of arenediazonium ions that can be prepared and because it does not depend on the reactivity of the electrochemically generated radical.

show abstract

“…2 The reduction of nitrobenzene has been studied at a number of electrode surfaces, including Hg, Pb, glassy carbon, Ag, Au, Pt, Sn, Cu, Devarda Cu, Ni, and Raney Ni. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] The reduction of nitrobenzene is proposed to occur as shown in Scheme I below, by a succession of twoelectron steps [3][4][5] 2e, 2H ϩ 2e, 2H ϩ 2e, 2H ϩ PhNO 2 r PhNO r PhNHOH r PhNH 2…”

mentioning

confidence: 99%

A Study of the Electrochemical Reduction of Nitrobenzene at Molybdenum Electrodes

Seshadri

Kelber

1999

J. Electrochem. Soc.

View full text Add to dashboard Cite

The reduction of nitrobenzene at Mo electrodes has been observed over a wide range of pH values from 4.4 to 13. Constant potential coulometry in conjunction with cyclic voltammetric studies show that under moderately alkaline and alkaline conditions, the final reduction product is the four-electron reduction product, namely, phenylhydroxylamine. This is the first report of nitrobenzene reduction at a Mo electrode.

show abstract

Reduction electrochimique du nitrobenzene, en milieu micellaire aqueux, a divers pH. Influence de la nature des tensio-actifs

Cited by 20 publications

References 17 publications

Effects of Sodium Dodecyl Sulfate, SDS, Micelles on the Electrochemical Behavior of a Model Arenediazonium Ion. 2. Estimation of the Association Constant of the Electrochemically Generated Aryl Radicals with SDS Micelles

Effects of Sodium Dodecyl Sulfate, SDS, Micelles on the Electrochemical Behavior of a Model Arenediazonium Ion. 2. Estimation of the Association Constant of the Electrochemically Generated Aryl Radicals with SDS Micelles

Partitioning of aryl radicals in micellar systems

A Study of the Electrochemical Reduction of Nitrobenzene at Molybdenum Electrodes

Contact Info

Product

Resources

About