Interactions entre les cations et les sucres. I. Évaluation de l'enthalpie libre d'interaction Ca2+ − D-(−)-ribose dans l'eau à 25 °C

1985 ◽  
Vol 63 (10) ◽  
pp. 2639-2643 ◽  
Author(s):  
Jean-Pierre Morel ◽  
Claude Lhermet
Keyword(s):  
Liquid Membrane ◽  
Specific Interaction ◽  
Pair Interaction ◽  
Hydroxyl Groups ◽  
Electrochemical Cells ◽  
Selective Electrode ◽  
Liquid Junction ◽  
Free Energy Of Transfer ◽  
Energy Of Transfer ◽  
Pair Interaction Parameter

The interaction of the two isomeric pentoses D-(−)-ribose and D-(−)-arabinose with the Ca2+ ion in aqueous solution is studied with the help of two types of electrochemical cells (with and without liquid junction) including a liquid-membrane Ca2+-selective electrode. Some of the D-(−)-ribose isomers contain a sequence of hydroxyl groups which can interact specifically with the cation. The measurement of the Gibbs free energy of transfer of Ca2+ between water and the sugar solutions allows one to calculate a characteristic pair-interaction parameter. This specific interaction can also be characterized by its association constant: β1 = 0.93. The two approaches are studied and their coherence is shown.

Comparison of the free energy of transfer of electrolytes, measured with cells without transference, with the sum of the free energies of the corresponding cations and anions with the Owen-cell on standard conditions

1983 ◽  
Vol 36 (10) ◽  
pp. 1997 ◽  
Author(s):  
K Schwabe ◽  
W Hoffmann ◽  
C Queck
Keyword(s):  
Free Energy ◽  
Free Energies ◽  
Liquid Junction Potential ◽  
Liquid Junction ◽  
Ph Values ◽  
Liquid Junction Potentials ◽  
Free Energy Of Transfer ◽  
Energy Of Transfer ◽  
Very High ◽  
Junction Potential

The comparison of S2ΔS1G°tr(E1) with the sum of the values for the corresponding cation and anion S2ΔS1G°tr(Ct+)~S2ΔS1G°tr(X-) (measured) with Owen cells, gained by double extrapolation and by the assumption that the liquid junction potential at 1→0 may be neglected) gives values which differ by not more than ±5%. Most of the investigated acids allow the conclusion that the pH values, measured in cells with transference, and having the same electrodes, give good information on the acidity of the organic solvent and its water mixtures, referred to the standard state in water. That means that the pH, changed to the same H+ concentration in the solvent compared with that in water, is essentially an effect of the free energy of transfer of the hydrogen ion and not of very high liquid junction potentials.

Liquid-membrane perchlorate-selective electrode

The Analyst ◽  
1987 ◽  
Vol 112 (10) ◽  
pp. 1355 ◽  
Author(s):  
Ajay K. Jain ◽  
Muzayan Jahan ◽  
Vipendra Tyagi
Keyword(s):  
Liquid Membrane ◽  
Selective Electrode

A SELECTIVITY STUDY ON THE ION-SELECTIVE ELECTRODE WITH A LIQUID MEMBRANE

1974 ◽  
Vol 3 (5) ◽  
pp. 493-496 ◽  
Author(s):  
Nobuo Yoshida ◽  
Nobuhiko Ishibashi
Keyword(s):  
Liquid Membrane ◽  
Ion Selective Electrode ◽  
Selective Electrode

Thermodynamics of transfer of Ph4C; scaled-particle theory and the Ph4As+/Ph4B− assumption for single ions

1979 ◽  
Vol 57 (15) ◽  
pp. 2004-2009 ◽  
Author(s):  
Michael H. Abraham ◽  
Asadollah Nasehzadeh
Keyword(s):  
Free Energy ◽  
Total Free Energy ◽  
Scaled Particle Theory ◽  
Free Energies ◽  
Particle Theory ◽  
Free Energy Of Transfer ◽  
Enthalpy And Entropy ◽  
Interaction Term ◽  
Energy Of Transfer ◽  
Entropy Of Transfer

Free energies of transfer of Ph4C from acetonitrile to 20 other solvents have been calculated from literature data. The contribution of the cavity term to the total free energy has been obtained from scaled-particle theory and Sinanoglu–Reisse–Moura Ramos theory. It is shown that there is little connection between the cavity term and the total free energy of transfer, and that there must be, in general, a large interaction term. If the latter is important for transfer of Ph4C, we argue that it must also be important for transfer of the ions Ph4As+ and Ph4B−. Previous suggestions that the interaction term is zero for transfer of these two ions are thus seen to be unreasonable. We also show, for six solvents, that the interaction term for Ph4C is very large in terms of enthalpy and entropy, and that scaled-particle theory seems not to apply to transfers of Ph4C between pure organic solvents.The free energy, enthalpy, and entropy of transfer of Ph4As+ = Ph4B− have been calculated by dividing the total transfer values into neutral and electrostatic contributions; reasonable agreement is obtained between calculated and observed values.

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