Anion transfer, water-nitrobenzene interfac

The effect of temperature on ion transfer across the water-nitrobenzene interface was studied for a series of six quaternary ammonium and phosphonium cations and two anions using cyclic voltammetry and equilibrium impedance measurements [115]. Standard entropies (A S ) and enthalpies (A iT ) of ion transfer have been evaluated from the experimentally accessible reversible half-wave potential ( "572 and standard Gibbs energy of transfer (A G ),... 

Gulaboski, R., V. Mirceski, and R Scholz, Determination of the standard Gibbs energies of transfer of cations and anions of amino acids and small peptides across the water nitrobenzene interface. Amino Acids, Vol. 24, (2003) p. 149. 

Figure 3.10a shows the time courses of the interfacial tension when the hydrophilic anions were added into the oil phase. The concentrations of these ions were set at 1.0 x 10 M. Here, desorption rate of each case was determined by 1/Ar, where At is the period for the interfacial tension to become the initial value again after the oscillation. The At values of each ion (Cl , Br and I ) were 110, 150 and 1000 seconds, respectively. Figure 3.10b shows the dependence of the desorption rate of the DS ions on AGi w of Cl , Br and 1 from nitrobenzene to water. We can consider that the desorption rate is proportional to the exponential of —AG - /RT R gas constant, T temperature). We plotted the dependence of the log value of the desorption rate (ln(l/Ar)) on the standard free energy of transfer from the interface to the water phase (AGi w). The solid straight line with the slope — /RT R 8.314 J mol , T 298 K) was obtained... 

Kakiuchi, T., J. Noguchi, and M. Senda, Kinetics of the transfer of monovalent anion across the nitrobenzene-water interface, J Electroanal Chem, Vol. 327, (1992) p. 63. 

Nishizawa, S., T. Yokobori, T. Shioya, and N. Teramae, Facihtated transfer of hydro-phihc anions across the nitrobenzene-water interface by a hydrogen-bonding iono-phore AppUeabUity for multianalyte deteetion, Chem Lett, (2001) p. 1058. 

Gulaboski, R., K. Riedl, and R Scholz, Standard Gibbs energies of transfer of halo-genate and pseudohalogenate ions, halogen substituted acetates, and cycloalkyl car-boxylate anions at the water I nitrobenzene interface, Phys Chem Chem Phys, Vol. 5, (2003) p. 1284. 

On the assumption that = 2, the theoretical values of the ion solvation energy were shown to agree well with the experimental values for univalent cations and anions in various solvents (e.g., 1,1- and 1,2-dichloroethane, tetrahydrofuran, 1,2-dimethoxyethane, ammonia, acetone, acetonitrile, nitromethane, 1-propanol, ethanol, methanol, and water). Abraham et al. [16,17] proposed an extended model in which the local solvent layer was further divided into two layers of different dielectric constants. The nonlocal electrostatic theory [9,11,12] was also presented, in which the permittivity of a medium was assumed to change continuously with the electric field around an ion. Combined with the above-mentioned Uhlig formula, it was successfully employed to elucidate the ion transfer energy at the nitrobenzene-water and 1,2-dichloroethane-water interfaces. 

An ITIES is formed between water and nitrobenzene (NB) using electrolytes with the picrate (Pic ) anion at the same activity (0.1 M). The electrolyte in water is Li Pic and that in NB, tetraphenylarsonium (TA" ") picrate. Given that the standard Gibbs energy of transfer of Pic is -4.6 kJmoU [18], estimate the Galvani potential difference at the interface. Use the data in table 8.11 to estimate the activity of Li" " in NB. 

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