Voltammetry of tetraalkylammonium picrates at water∣nitrobenzene and water∣dichloroethane microinterfaces; influence of partition phenomena

Sladkov, Vladimir; Guillou, Valéry; Peulon, S.; L’Her, Maurice

doi:10.1016/j.jelechem.2004.06.027

Cited by 11 publications

(13 citation statements)

References 41 publications

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“…Especially, in the w/NB system, there is little difference between Picand Me4N + in the ratio, D w /D o , of the diffusion coefficients in both phases; according to electrochemical measurements, the D w /D NB values were estimated to be 1.8 to 3.0 for Picand 2.0 to 2.6 for Me4N + . 5,8,11 That is, the D w /D NB value for Picis nearly equal to that for…”

Section: Reduction Of Reported Individual Distribution Constants Of Amentioning

confidence: 90%

“…Sladkov et al 11 have reported that Me4N + and Pichave almost the same half-wave potentials (Δf1/2) for ion transfer at the w/NB interface, and Et4N + and Pichave the same Δf1/2 values at the w/DCE interface. Especially, in the w/NB system, there is little difference between Picand Me4N + in the ratio, D w /D o , of the diffusion coefficients in both phases; according to electrochemical measurements, the D w /D NB values were estimated to be 1.8 to 3.0 for Picand 2.0 to 2.6 for Me4N + .…”

Section: Reduction Of Reported Individual Distribution Constants Of Amentioning

confidence: 99%

“…[1][2][3][4] One of their interests is based on grounds for an evaluation of standard potentials (Δftr 0 ) with respect to single ion transfers at immiscible liquid/liquid interfaces. [5][6][7][8][9][10][11][12][13][14][15] In particular, nitrobenzene (NB) and 1,2-dichloroethane (DCE) have been employed as major organic (o) solvents or diluents constituting a phase separated at the interface. [4][5][6][8][9][10][11][12][13][14][15] However, the distribution properties of MA into such diluents with its ion-pair formation in water (w)-and o-phases have not been adequately studied.…”

Section: Introductionmentioning

confidence: 99%

“…3,4 Also, it seems to be difficult to electrochemically clarify ion-pair formation in both phases, since the o-phases or both phases contain excess supporting electrolytes for measurements of the ion-transfer at the interfaces in many cases. 4,6,8,11,[13][14][15] Apparent distribution constants (KD,ML) of the complex ions (ML + ) composed of cations (M + ) with crown compounds (L) and their complex formation ones (KML org ) in the o-phases saturated with w have been reported for the solvent extraction of MA by L. 16,17 On the other hand, the same constants have been determined by electrochemical measurements at the w/NB and w/DCE interfaces, and it has been based on the Δftr 0 values for M + . 6,18,19 However, agreements between the KD,ML or KML NB values determined by these methods have been poor.…”

Section: Introductionmentioning

confidence: 99%

“…In the present study, we first examined the validity of the extra-thermodynamic assumption 1 standardizing the ion transfer at the interfaces by determining apparent distribution constants (KD,±) of M + or Aby solvent-extraction experiments of some MA into the DCE-and NB-phases. Here, tetraethylammonium picrate (Et4NPic) for the w/DCE extraction system and tetramethylammonium picrate (Me4NPic) for the w/NB system were selected as a standard MA from their electrochemical properties 11,8 reported by cyclic-voltammetric measurements at the corresponding interfaces. Secondly, using the Δftr 0 values of these picrate ions as standards, some Δftr 0 values for the w/DCE and w/NB distribution systems were determined at 25 C. In addition to the above, the thus-obtained log KD,± values were applied for computation of the equilibrium constants, namely KD,ML and KML NB , in extraction systems 16 with MA = NaMnO4 and L = benzo-3m-crown-m ethers with m = 5 and 6.…”

Section: Introductionmentioning

confidence: 99%

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Extraction of Some Univalent Salts into 1,2-Dichloroethane and Nitrobenzene: Analysis of Overall Extraction Equilibrium Based on Elucidating Ion-pair Formation and Evaluation of Standard Potentials for Ion Transfers at the Interfaces between Their Diluents and Water

et al. 2011

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Sodium permanganate, sodium picrate (NaPic), Bu(4)NPic, Me(4)NPic, and Et(4)NPic were extracted at an ionic strength of 2 × 10(-5) to 0.08 mol dm(-3) and 25°C from water (w)-phases into the organic (o)-ones, 1,2-dichloroethane (DCE) and nitrobenzene (NB). Thereby, apparent distribution constants (K(D,±)) of the anions (A(-)) or the cations (M(+)) and ion-pair formation ones (K(MA)(org)) of the univalent salts (MA) in the o-phases were determined at 25 °C, where K(D,±) = ([A(-)](o)[M(+)](o)/[A(-)][M(+)])(1/2) = (K(D,A)K(D,M))(1/2) and K(MA)(org) = [MA](o)/[M(+)](o)[A(-)](o). Also, the K(ex) and K(D,MA) values with A(-) = Pic(-), MnO(4)(-) were estimated from the relations K(ex) (= [MA](o)/[M(+)][A(-)]) = K(MA)(org)(K(D,±))(2) and = K(MA)K(D,MA), respectively. Standard potentials (Δψ(tr)(0)) for ion transfers at the w/DCE and w/NB interfaces were evaluated from the log K(D,A) or log K(D,M) values by assuming the relations K(D,Pic) = K(D,Et4N) and = K(D,Me4N), respectively. The thus-obtained Δψ(tr)(0) values, especially for the w/DCE system, were in good agreement with the values based on the extra-thermodynamic assumption for Ph(4)As(+) and BPh(4)(-) transfers at the interfaces. In the present extraction systems, the ion-pair formation of MA in the w- and o-phases was less effective in the determination of their distribution constants into the two o-phases.

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Section: Reduction Of Reported Individual Distribution Constants Of Amentioning

confidence: 90%

Section: Reduction Of Reported Individual Distribution Constants Of Amentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Extraction of Some Univalent Salts into 1,2-Dichloroethane and Nitrobenzene: Analysis of Overall Extraction Equilibrium Based on Elucidating Ion-pair Formation and Evaluation of Standard Potentials for Ion Transfers at the Interfaces between Their Diluents and Water

et al. 2011

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Electrocatalysis at Liquid–Liquid Interfaces

Samec

2011

Catalysis in Electrochemistry

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Le transfert assisté de protons utilisant deux porphyrines "base libre" telles que le H 2 TPP et H 2 OEP a été étudié à l'interface eau|1,2-DCE. La formation de di-acid H 4 TPP 2+ et H 4 OEP 2+ , liée à la double protonation de H 2 TPP et H 2 OEP au niveau des nitrogènes tertiaires dans le cycle, a été observée à l'interface par voltamétrie du transfert d'ions ainsi que par spectroscopie en UV visible. De plus, les derivés neutres et ionisées de H 2 TPP ont été déterminés dans le "diagramme de partition ionique" pour illustrer les diverses contributions de H 2 TPP.

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Partition of dissociable compounds in two‐phase liquid systems: a theoretical and experimental study

Pradines¹,

Despoux²,

Claparols³

et al. 2006

J of Physical Organic Chem

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The partition at equilibrium, in a two-phase liquid system, of a compound dissociated in one phase, or both, is expressed in terms of general equations and analyzed. Dissociation in the second phase, even weak, has a nonnegligible influence. The distribution ratio depends strongly on the concentration and can even be reversed in certain cases. All the partition and dissociation constants in each phase can be obtained from the concentrations at equilibrium measured under some given conditions. In less favorable cases, an apparent partition constant can still be estimated. This is illustrated by an experimental study, in the water/dichloromethane system, involving the partition of picric acid and cetyltrimethylammonium bromide (CTAB) followed by UV-Visible spectroscopy, and of a series of tetraalkylammonium bromides (ethyl, propyl, and butyl) assayed by mass spectroscopy.

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Voltammetry of tetraalkylammonium picrates at water∣nitrobenzene and water∣dichloroethane microinterfaces; influence of partition phenomena

Cited by 11 publications

References 41 publications

Extraction of Some Univalent Salts into 1,2-Dichloroethane and Nitrobenzene: Analysis of Overall Extraction Equilibrium Based on Elucidating Ion-pair Formation and Evaluation of Standard Potentials for Ion Transfers at the Interfaces between Their Diluents and Water

Extraction of Some Univalent Salts into 1,2-Dichloroethane and Nitrobenzene: Analysis of Overall Extraction Equilibrium Based on Elucidating Ion-pair Formation and Evaluation of Standard Potentials for Ion Transfers at the Interfaces between Their Diluents and Water

Electrocatalysis at Liquid–Liquid Interfaces

Partition of dissociable compounds in two‐phase liquid systems: a theoretical and experimental study

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