THE AQUEOUS SOLUTION BEHAVIOR OF LARGE UNIVALENT IONS. A NEW TYPE OF ION-PAIRING<sup>1a</sup>

Diamond, R.M.

doi:10.1021/j100806a002

Cited by 277 publications

(89 citation statements)

References 2 publications

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“…26 In solution, the solvation and the interactions of the ions or ion pairs with the solvent determine the unique properties of these systems. 34 The volumetric properties of electrolyte and nonelectrolyte solutions have been particularly informative in elucidating the solute-solute and solute-solvent interactions that exist in these solutions.…”

Section: Introductionmentioning

confidence: 99%

Volumetric Properties, Viscosities, and Isobaric Heat Capacities of Imidazolium Octanoate Protic Ionic Liquid in Molecular Solvents

2010

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Densities (F), viscosities (η), and isobaric heat molar capacities (C p ) of binary mixtures containing imidazolium octanoate, [Im][C 7 CO 2 ], a protic ionic liquid (PIL), with four molecular solvents, water, acetonitrile, ethanol, and 1-octanol, are determined as a function of temperature from (298.15 to 323.15) K and within the whole composition range at atmospheric pressure. Excess molar volumes, V E , excess molar heat capacities, C p E , and the deviation from additivity rules of viscosities, ∆η, of imidazolium octanoate solutions were then deduced from the experimental results, as well as apparent molar volumes, V φi , and partial molar volumes, V j m,i . Results are discussed according to the nature of the interaction between the PIL and the molecules and the effect of temperature. The excess Gibbs energies of activation of viscous flow (∆G *E ) for these systems were then calculated at 298.15 K. The excess isobaric heat capacities, C p E , of binary ([Im][C 7 CO 2 ] + solvent) systems, depend also of the nature of the molecular solvent in mixture. The excess properties were then correlated, at each temperature, as a function of composition by a Redlich-Kister-type equation. Finally results have been discussed in terms of molecular interactions and molecular structures in these binary mixtures, and thermodynamic properties of investigated binary mixtures were then compared to literature values together to investigate the impact of the nature of the solvent on these reported properties.

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Section: Introductionmentioning

confidence: 99%

Volumetric Properties, Viscosities, and Isobaric Heat Capacities of Imidazolium Octanoate Protic Ionic Liquid in Molecular Solvents

2010

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“…Dia mond [4] coined the term 'water structureenforced ion pairing' to refer to the interac tion between large, bulky cations and anions in water. Sadek and Fuoss [5] and Winstein et al [6] later introduced the terms 'loose' and 'tight' ion pairs to describe solvent coordi nated and uncoordinated ion pairs, respec tively.…”

Section: Introductionmentioning

confidence: 99%

The Possibility of Lidocaine Ion Pair Absorption Through Excised Hairless Mouse Skin

Nash

Mehta

Matias

et al. 1992

Skin Pharmacol Physiol

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The purpose of the present research was to test the ion pair absorption hypothesis with respect to the topical route of drug delivery. The experiment consisted of preparing various lido-cainen-alkanoate ion pairs, then characterizing them by proton magnetic resonance spectroscopy, elemental analysis and conductivity. Percutaneous absorption studies through excised hairless mouse skin were carried out using ethanolic solution of radiolabeled ¹⁴C-lidocaine-octanoate, ¹⁴C-lido-caine-decanoate and ¹⁴C-lidocaine-dodecanoate. Studies were conducted under steady-state conditions using Bronaugh’s flow-through apparatus and normal saline as the receptor fluid. Ethanolic solution of a lidocaine base served as a control. The apparent differences in flux between lidocaine and the various ion pairs were statistically significant (p < 0.05). The differences among the fluxes of the various ion pairs were not statistically significant (p > 0.05), nor were the differences in lag times (p > 0.05). The difference between the flux values of lidocaine- 1-¹⁴C-dodecanoate and ¹⁴C-lidocaine-dodecanoate infers that lidocaine-dodecanoate did not cross the excised, full-thickness, hairless mouse skin as an intact 1:1 ion pair. The formation of weakly associated ion pairs was suggested by the apparent low-association constants (K_a = 15-17 liters/mol) obtained at 25 °C in methanol by conductometric analysis.

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“…These effects are considered to be the distortion of the stream-lines by the solute molecules or ions in viscous flow and the lengthening of the effective paths of the n~oviilg particles in coilductance and diffusion. This picture accounts qualitatively for the above results on the basis thal the obstructive effect increases regularly with ion size, and that the tetraall~plarnmoniu~~~ and fatty acid ions approximate spheres, However, ion-solvent interactions, such as the postulated tightening or iinmobilization of the surrounding water structure by tetraalkg-lamn~o~lium cations ancl fatty acid anions (19,20,21), may also play a role, and it is impossible on the basis of the present experiments to distinguish between the two effects. Thc same uncertaiilties are involved in attempting to account for the consistently and distinctly higher ziT values and the lower q,,1 values in chloride-tartrate solutions as compared to acetate-tartrate (Fig.…”

Section: Concentrationmentioning

confidence: 47%

Effect of Electrolyte Environment on Divalent Tartrate Ion Mobility

Nichol¹,

Heikkinen²,

Glass³

1965

Can. J. Chem.

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The variation of the electrophoretic mobility, ZLT, of divalent tartrate ion with changing electrolyte environment has been studied. Mobilities were determined from boundary velocity ~neasurernents a t 1.00 "C in the Tiselius electrophoresis apparatus. The solutions used, which were adjusted to pH 8.3-8.5, \\.ere principally either 0.04667 ill CJ or 0.01 ill C?T -0.11 i l l Cry, where C+, T-, and A-are, respectively, a univalent cation, divalent tartrate ion, and a univalent anion. Iielative viscosities, a,,l, of a number of these solutions were also obtained. For a given anion environment, the variation of U T with clla~lging cation is characterized by a minimum a t sodium and a maximum a t tetra~nethylam~noilium for a series of six alkali metal and tetraalkylammonium ions. For the alBali metal cations and for tetrapropylammoniu~u ion, Z I T undergoes a distinct decrease \\.hen the solution is cha~iged froin 0.04667 i l l C?T to 0.01 ild C?T -0.11 M CC1. For all solutions containing an anion A-, ZIT decreases with illcreasing hydrocarbon content of A-for a given cation. Possible ion association, obstruction, and ion-solvent interaction effects are considered.In Dole's development of the steady state moving boundary theory for strong electrolytes (I), it is assumed that the mobilities of the ions in solutions of electrolytes vary by the same proportional factor with change in composition, that is, the relative mobilities are constant. This assunlption makes possible an elegant mathematical treatinent for the general case of n ions. Only the relative mobilities appear in the equations, since the ion mobilities themselves always occur in the fundamental moving boundary relationship as ratios. Thus, the inuch poorer assuinption of constant ion inobilities is avoided. The assumed constancy of relative inobilities is justified to the extent that the final results of a moving boundary experiment (boundary velocities and refractive index gradients), predicted froin the initial conditions by the Dole theory, have been found to agree to within lye or less of the observed values for uni-univalent electrolytes (2). Also, for simple systems involving weak electrolytes, the application of moving boundary theory, which includes the assumption that the relative mobilities of the ionic subspecies are constant, yields predictions in accord with observed results to within about lyo (3). Nevertheless, especially in experiments with strong electrolyte solutions containing inore highly charged ions, pronounced mobility changes can occur. For example, we have observed (Table 111) that the decrease of divalent tartrate ion mobility with increasing ionic strength varies markedly with the nature of the solutions in which it is measured. The value in 0.04667 i l l disodium tartrate is about 4y0 lower than that in 0.03333 116disodiuin tartrate, while in a n~ixture of 0.11 M sodium acetate and 0.01 M disodium tartrate, the decrease is about 13y0, although the change in ionic strength, 0.04 units, is the same in both cases. These

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THE AQUEOUS SOLUTION BEHAVIOR OF LARGE UNIVALENT IONS. A NEW TYPE OF ION-PAIRING^1a

Cited by 277 publications

References 2 publications

Volumetric Properties, Viscosities, and Isobaric Heat Capacities of Imidazolium Octanoate Protic Ionic Liquid in Molecular Solvents

Volumetric Properties, Viscosities, and Isobaric Heat Capacities of Imidazolium Octanoate Protic Ionic Liquid in Molecular Solvents

The Possibility of Lidocaine Ion Pair Absorption Through Excised Hairless Mouse Skin

Effect of Electrolyte Environment on Divalent Tartrate Ion Mobility

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THE AQUEOUS SOLUTION BEHAVIOR OF LARGE UNIVALENT IONS. A NEW TYPE OF ION-PAIRING1a

Cited by 277 publications

References 2 publications

Volumetric Properties, Viscosities, and Isobaric Heat Capacities of Imidazolium Octanoate Protic Ionic Liquid in Molecular Solvents

Volumetric Properties, Viscosities, and Isobaric Heat Capacities of Imidazolium Octanoate Protic Ionic Liquid in Molecular Solvents

The Possibility of Lidocaine Ion Pair Absorption Through Excised Hairless Mouse Skin

Effect of Electrolyte Environment on Divalent Tartrate Ion Mobility

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THE AQUEOUS SOLUTION BEHAVIOR OF LARGE UNIVALENT IONS. A NEW TYPE OF ION-PAIRING^1a