Solvation of ions. XXVII. Comparison of methods to calculate single ion free energies of transfer in mixed solvents

1981 ◽  
Vol 10 (12) ◽  
pp. 847-861 ◽  
Author(s):  
K. K. Kundu ◽  
A. J. Parker
Keyword(s):  
Mixed Solvents ◽  
Comparison Of Methods ◽  
Free Energies ◽  
Free Energies Of Transfer ◽  
Solvation Of Ions

Ionization of ethylene glycol in isodielectric acetonitrile + ethylene glycol mixtures at 25 °C

1979 ◽  
Vol 57 (18) ◽  
pp. 2470-2475 ◽  
Author(s):  
Kumardev Bose ◽  
Kiron K. Kundu
Keyword(s):  
Free Energy ◽  
Ethylene Glycol ◽  
Mixed Solvents ◽  
Solvent Composition ◽  
Free Energies ◽  
Emf Measurements ◽  
Free Energies Of Transfer ◽  
Mixed Systems

The autoprotolysis constants (Ksm) of ethylene glycol in isodielectric acetonitrile + ethylene glycol mixtures have been determined at 25 °C from emf measurements on the cell[Formula: see text]From these values, those of δΔG0, the free energy of ionization of ethylene glycol in these mixed solvents relative to that in pure glycol, have been computed. The nature of variation of δΔG0 with solvent composition has been compared with that in two other mixed systems: water + ethylene glycol and methanol + 1,2-propanediol and the intrinsic differences between the solvation characteristics of the various solvents have been pointed out. The standard free energies of transfer of the glycoxide ion, ΔGt0(OEg−), from pure glycol to acetonitrile + glycol mixtures have also been estimated using ΔGt0(H+) values obtained earlier. The glycoxide ion is increasingly desolvated as the acetonitrile content of the solvent increases, as indicated by increasingly positive values of ΔGt0(OEg−). This behaviour has been compared with those of ΔGt0(H+) and ΔGt0(Cl−) determined previously.

Solvation of ions. Some applications. III. Solutions of copper(I) salts in water containing ligands

1977 ◽  
Vol 30 (8) ◽  
pp. 1661 ◽  
Author(s):  
AJ Parker ◽  
DA Clarke ◽  
RA Couche ◽  
G Miller ◽  
RI Tilley ◽  
...  
Keyword(s):  
Free Energies ◽  
Molar Excess ◽  
Free Energies Of Transfer ◽  
Reduction Potentials ◽  
Solvation Of Ions

Solutions of copper(II) and copper(I) sulphate in water containing acetonitrile have applications in the hydrometallurgy of copper. The potentials (n.h.e.) of the Cu+/Cu; the Pt/Cu2+, Cu+, and the Cu2+/Cu electrodes in water containing a large molar excess of various copper(I) bases and various counter-anions have been measured. Free energies of transfer of copper(I) ions from water to water containing the bases are calculated. ΔGtr(Cu+) at 25�C becomes less exoenergetic for water containing the bases in the following order: CN- >> S2O32- > Me2NCHS > KI > NH3 > C5H5N > KBr > KCl > C3H5OH ≥ MeCN, CO, C2H4 > C3H6. The reduction potentials of CuSO4/Cu2SO4 in acidic saturated copper(II) sulphate solutions and a range of Cu2SO4 concentrations in acetonitrile- water mixtures show that CuSO4/MeCN/H2O is a powerful oxidant, comparable in strength to acidic iron(III) sulphate in water. Acetonitrile is the preferred base for the processing of copper by way of solutions of copper(I) sulphate.

Determination of absolute transfer free energies of hydroxyl ion from water to aqueous 2-methoxy ethanol

1981 ◽  
Vol 59 (7) ◽  
pp. 1153-1159 ◽  
Author(s):  
Abhijit Bhattacharya ◽  
Asim K. Das ◽  
Kiron K. Kundu
Keyword(s):  
Ethylene Glycol ◽  
Mixed Solvents ◽  
Aqueous Mixtures ◽  
Free Energies ◽  
Free Energies Of Transfer ◽  
Hydroxyl Ion ◽  
Relative Stabilization ◽  
Solvent Systems ◽  
Reference Electrolyte

Absolute standard free energies of transfer ΔGt0 of OH− from water to aqueous mixtures of 2-methoxy ethanol (ME) have been evaluated at 298.15 K by combining the apparent transfer free energies of the lyate ion that were obtained from the standard emf's of the double cell:[Formula: see text]and that from the autoionization constants of these mixed solvents determined by use of the cell comprising H2– and Ag–AgCl electrodes. The required ΔGt0 values of K+ and H+ were determined earlier using the well-known tetraphenyl arsonium tetraphenyl boride (TATB) reference electrolyte method. These values and their non-Born type contributions in particular, are found to be increasingly positive in water-rich compositions, indicating that the relative stabilization of OH− and the acidity of the mixed solvents decrease with increasing cosolvent composition. These, when compared with those in aqueous mixtures of ethylene glycol and 1,2-dimethoxy ethane, are found to lie intermediate between the latter solvent systems conforming to what is expected from the structural and electronic features of the cosolvents.

Solvation of ions. XXVI. Free energies of transfer of ions to multi-site solvents and solvent mixtures

1978 ◽  
Vol 31 (6) ◽  
pp. 1181 ◽  
Author(s):  
AJ Parker ◽  
WE Waghorne
Keyword(s):  
Solvent Mixtures ◽  
Free Energies ◽  
Free Energies Of Transfer ◽  
Solvation Of Ions ◽  
Solvent Transfer

The free energies of solvent transfer of Ag+, K+, Cl-, Br-, I- and ClO4- from acetonitrile to glycolonitrile, 3-hydroxypropionitrile and mixtures of 2,2,2-trifluoroethanol or water with acetonitrile are reported. ��� The anion-solvating properties of a series of hydroxylic solvents decrease by 24 kJ mol-1 in the order CF3CH2OH > CNCH2OH > CNCH2CH2OH > CH3OH > CH3CH2OH; Ag+-solvating properties decrease by 70 kJ mol-1 in the order CH3CN > HOCH2CH2CN > HOCH2CN > CH3CH2OH > CF3CH2OH; and the K+- solvating properties decrease by 27 kJ mol-1 in the order CH3CN > HOCH2CH2CN ≈ CH3OH ≈ HOCH2CN ≈ CH3CH2OH > CF3CH2OH. It is not possible to make more than qualitative generalizations as to the ion-solvating properties of solvent mixtures if only the solvating properties of the pure components are known. Multi-site solvents like CNCH2OH are compared with related equimolar mixtures, like CH3CN/HOH, in their ability to solvate ions.

Sign in / Sign up

Export Citation Format

Share Document