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

Pradines, Vincent; Despoux, Sabrina; Claparols, Catherine; Martins, Nathalie; Micheau, J. C.; Lavabre, D.; Pimienta, Véronique

doi:10.1002/poc.1085

Cited by 13 publications

(26 citation statements)

References 35 publications

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“…The extraction data thus obtained are summarized in Table 1. The log ex values of the extraction into benzene, Bz, and chloroform, CF, were in accord with those [1,2] reported before by Takeda et al Although the measuring temperature was not described, the log ex value (=2.28 [10]) estimated previously for the dichloromethane, DCM, system was also close to our value (=2.462). From the log HPic values in Table 1, one can see easily that differences among the present values, the average ones, have no objection to comparisons among the ex values or component equilibrium constants, except for the cyclohexane, cHex, system [8].…”

Section: Determination Of Ex and Dhpicsupporting

confidence: 93%

“…Picric acid (HPic) has been widely used for the source of pairing anions in solvent extraction [1][2][3][4][5], application to selective sensors [6], sequential injection analysis with it [7], its separation science [8,9], theoretical study for its partition [10], its distribution into ionic liquids [11], and so on. Also, many authors have studied extraction and separation of many metal ions by crown compounds from water (w) into various diluents [1][2][3][12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

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Distribution of Picric Acid into Various Diluents

Kudo

Takahashi

Katsuta

2013

Journal of Chemistry

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Extraction constants, defined as ex = [HPic] o /[H + ][Pic − ], for picric acid (HPic) into ten diluents were spectrophotometrically determined at 298 K, where the subscript "o" refers to an organic (o) phase which is composed of the diluent. Their values for the HPic extraction into benzene and chloroform were fairly consistent with those reported before. From the ex values, distribution constants (D,HPic) of HPic into the o phases were estimated using the thermodynamic relation ex = D,HPic HPic , where HPic corresponds to a protonation constant of Pic − in water. Thereby, contributions of functional groups, such as-Cl and-CH 3 , involved in the diluents molecules to D,HPic were discussed. The same discussion was also applied for the distribution of the ion pair, composed of CdPic 2 and 18-crown-6 ether, into the diluents.

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Section: Determination Of Ex and Dhpicsupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Distribution of Picric Acid into Various Diluents

Kudo

Takahashi

Katsuta

2013

Journal of Chemistry

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“…[16] We assume that consideration of contact IPs, as we have done in our work, is relevant and that it should provide valuable insights into the increase of association constants.…”

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confidence: 99%

Amphiphilic Organic Ion Pairs in Solution: A Theoretical Study

2007

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The macroscopic manifestation of hydrophobic interactions for amphiphilic organic ion pairs (tetraalkylammonium-anion) has been shown experimentally by measuring their association constants and their affinity with the organic phase. Beyond a certain size, there is a direct relation between association constants and chain lengths in tetraalkylammonium ions. We propose to cast a bridge between these results and geometrical properties considered at the level of a single ion pair by means of quantum chemistry calculations performed on model systems: trimethylalkylammonium-pentyl sulfate instead of tetraalkylammonium-dodecyl sulfate. Two limiting cases are considered: head-to-head configurations, which yield an optimal electrostatic interaction between polar heads, and parallel configurations with a balance between electrostatic and hydrophobic interactions. All properties (geometries, complexation energies, and atomic charges) were obtained at the MP2 level of calculation, with water described by a continuum model (CPCM). Dispersion forces link hydrocarbon chains of tetraalkylammonium ions and pentyl sulfate, thus yielding (for the largest ion pairs) parallel configurations favored with respect to head-to-head geometries by solute-solvent electrostatic interactions. Given the small experimental association energies, we probe the accuracy limit of the MP2 and CPCM methods. However, clear trends are obtained as a function of chain length, which agree with the experimental observations. The calculated monotonic stabilization of ion pairs when the hydrocarbon chain increases in length is discussed in terms of electrostatic interactions (between ions and between ion pairs and water), dispersion forces, and cavitation energies.

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“…10,11 We have, in a recent article, 12 extended this methodology to the partition of ionic surfactants. In this case, due to dissociation in the aqueous phase, the dependence of partition on initial concentration is no more linear 13 and deserves the exploration of a larger concentration domain. Modeling water/air adsorption isotherms obtained before and after partition of ionic surfactants allows the determination of the apparent partition coefficient K app ¼ K p /K d where K d is the dissociation constant in water.…”

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confidence: 99%

Autocatalysis in liquid/liquid surfactant transfer

2011

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Equilibrium and transfer properties of two surfactants (a non-ionic one, Brij5, and a cationic one, CTAB) were studied in water/oil biphasic systems. Water/air surface tension measurements provide information on both the partition coefficient and also on the type of aggregates formed: classical micelles or swollen micelles (oil-inwater microemulsion). A clear correlation is established between the type of aggregates and the kinetics recorded during transfer of the surfactant from the organic to the aqueous phase. Indeed, an accelerating kinetics is obtained for every system leading to the formation of swollen micelles. This is the first example of autocatalytic dynamics observed in biphasic conditions for a non-reactive system. This non-linear behavior, correlated to the Critical Aggregation Concentration, confirms the contribution of an interface mediated pathway, known as the ''budding mechanism'', to the formation of microemulsion for both non-ionic and ionic surfactants.

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

Cited by 13 publications

References 35 publications

Distribution of Picric Acid into Various Diluents

Distribution of Picric Acid into Various Diluents

Amphiphilic Organic Ion Pairs in Solution: A Theoretical Study

Autocatalysis in liquid/liquid surfactant transfer

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