Solubilities in aqueous mixtures oft-butanol andtrans-dichlorotetra(3-alkylpyridine) cobalt(III) hexachlororhenate(IV): Gibbs energies of transfer of the complex cations

1993 ◽  
Vol 22 (10) ◽  
pp. 883-894 ◽  
Author(s):  
Gehan M. El-Subruiti ◽  
Cecil F. Wells ◽  
Ibrahim M. Sidahmed
Keyword(s):  
Aqueous Mixtures ◽  
Gibbs Energies ◽  
Gibbs Energies Of Transfer

Gibbs energies of transfer of individual ions from water to acetone + water solvents

1989 ◽  
Vol 67 (8) ◽  
pp. 1268-1273 ◽  
Author(s):  
Mahmoud Mohamad Elsemongy ◽  
Ahmed Ahmed Abdel-Khalek
Keyword(s):  
Glass Electrode ◽  
Aqueous Mixtures ◽  
Free Energies ◽  
Emf Measurements ◽  
Gibbs Energies ◽  
Electrode Potentials ◽  
Gibbs Energies Of Transfer ◽  
Acetone Water ◽  
Alkali Metal Halides ◽  
Dipolar Aprotic Solvents

The standard absolute potentials of hydrogen, Ag–AgX (X = Cl, Br, and I) and M/M+ (M = Li, Na, K, Rb, and Cs) electrodes in nine different acetone + water solvents containing up to 80 wt. % acetone were determined from the emf data at 25 °C of the cells: glass electrode/HCl (m), solvent/AgCl–Ag and glass electrode (M)/MX (m), solvent/AgX–Ag. The standard Gibbs free energies of a transfer of halogen acids and alkali metal halides as well as their constituent individual ions from water to the respective solvents were computed. The observed increases in [Formula: see text] values of all ions with increasing acetone content of the solvent and their relative order in each solvent were interpreted and discussed. A comparison of the present results with those obtained earlier in the dimethyl sulphoxide (DMSO) + water solvents shows the different nature of the two dipolar aprotic solvents, acetone and DMSO, in their aqueous mixtures. Keywords: acetone + water solvents, electrode potentials, emf measurements, individual ions, transfer free energies.

Solute–solvent effects in the dissociation of thymolsulfonephthalein (an uncharged acid) in aqueous mixtures of acetonitrile (ACN), urea, and dimethyl sulfoxide (DMSO)

1986 ◽  
Vol 64 (8) ◽  
pp. 1521-1526 ◽  
Author(s):  
A. L. De ◽  
A. K. Atta
Keyword(s):  
Solvent Effect ◽  
Dimethyl Sulfoxide ◽  
Solvent Effects ◽  
Mixed Solvent ◽  
Dissociation Constants ◽  
Aqueous Mixtures ◽  
Solvent Interactions ◽  
Gibbs Energies ◽  
Gibbs Energies Of Transfer ◽  
Solvent Systems

The thermodynamic first dissociation constants, [Formula: see text] of thymolsulfonephthalein (H2A), an uncharged acid, have been determined at 25 °C in aqueous mixtures of 10, 30, 50, 70, and 80 wt% acetonitrile (ACN), 11.52, 20.31, 29.64, and 36.83 wt% urea, 20, 40, 60, and 80 wt% dimethyl sulfoxide (DMSO) by spectrophotometric measurements. The solvent effect represented by ∂(ΔG0) = 2.303RT[p(sK)N − p(wK)N] is found to increase in ACN + H2O system as mol% ACN increases in the solvent. In contrast, the corresponding values in urea + H2O as well as DMSO + H2O solvent systems decrease with increase in proportion of organic component in the solvent, the decrease being sharp in urea + H2O. The results have been discussed in terms of the standard Gibbs energies of transfer of H+ from water to the mixed solvent, [Formula: see text] and the relative values of the standard Gibbs energies of transfer of HA−, [Formula: see text] and of [Formula: see text] in all the solvent systems. The overall dissociation behaviour of the acid (H2A) is found to be dictated by the specific solute-solvent interactions of the species participating in the dissociation equilibria.

Spectrophotometric study of the dissociation of p-nitroanilinium ion in a binary aqueous-dipolar aprotic solvent system (H2O + acetonitrile) at 25 °C: effect of the solvent

1984 ◽  
Vol 62 (9) ◽  
pp. 1776-1779
Author(s):  
A. L. De ◽  
T. K. De
Keyword(s):  
Solvent Effect ◽  
Dissociation Constants ◽  
Spectrophotometric Study ◽  
Solvent System ◽  
Individual Species ◽  
Aqueous Mixtures ◽  
Gibbs Energies ◽  
Gibbs Energies Of Transfer ◽  
Aqueous Mixture ◽  
The Individual

Thermodynamic dissociation constants (SK) of p-nitroanilinium ion (BH+) have been determined at 25 °C in aqueous solutions containing 20, 40, 60, and 80 wt% acetonitrile (ACN) by spectrophotometric measurements. Standard Gibbs energies of transfer, [Formula: see text] (B) of p-nitroaniline (B) from water to other solvents have been evaluated from the measurement of solubilities at 25 °C. Solvent effect on the dissociation of the acid (BH+), δ(ΔG0) = 2.303RT[p(sK) − p(wK], results in a characteristic minimum with a change in the solvent composition. The result in this protic – dipolar aprotic mixture (H2O + ACN) has been compared with that in aqueous mixture of protic solvent (H2O + ethylene glycol) available from literature. The solvent effect has been discussed in terms of the standard Gibbs energies of transfer [Formula: see text], from water to aqueous mixtures of organic co-solvent of the uncharged base (B), the hydrochloride of the base (BHCl), and hydrochloric acid (HCl) and also in terms of the individual species involved in the dissociation process. The results indicate that solvent effect on dissociation is an involved process, guided by the combined effects of various types of solute–solvent interactions of the Brønsted acid and its conjugate base in addition to the relative solvent basicities.

Activity Coefficients and Gibbs Energies of Transfer of Tetraalkylammonium Dianilinetetraisothiocyanatochromates(III)

1994 ◽  
Vol 59 (8) ◽  
pp. 1738-1744
Author(s):  
Vladislav Holba
Keyword(s):  
Activity Coefficients ◽  
Transfer Functions ◽  
Butyl Alcohol ◽  
Methyl Ethyl ◽  
Tetraalkylammonium Ions ◽  
Ionic Transfer ◽  
Gibbs Energies ◽  
Gibbs Energies Of Transfer ◽  
Acetonitrile Solutions ◽  
Mixed Systems

The solubilities of tetraalkylammonium dianilinetetraisothiocyanatochromates(III) (alkyl = methyl, ethyl, 1-propyl, and 1-butyl) in water, water - methanol, water - tert-butyl alcohol and water - acetonitrile solutions were measured at 25 °C. The results were used to evaluate the activity coefficients and Gibbs energies of transfer of the saturating salts from water to the mixed systems. The Gibbs energies of transfer of the [Cr(C6H5NH2)2(NCS)4]- ion were obtained by means of known ionic transfer functions for the tetraalkylammonium ions based on the TATB assumption.

The distribution of branched octanols between dodecane and water

1985 ◽  
Vol 63 (4) ◽  
pp. 789-792 ◽  
Author(s):  
Norman H. Sagert ◽  
Danny W. P. Lau
Keyword(s):  
Thermodynamic Functions ◽  
Distribution Data ◽  
Standard Entropy ◽  
Standard Thermodynamic Functions ◽  
Enthalpies Of Transfer ◽  
Data Standard ◽  
Gibbs Energies ◽  
Gibbs Energies Of Transfer ◽  
Branched Chain ◽  
Entropy Of Transfer

The distribution of four branched chain octanols, 3-ethyl-3-hexanol, 4-ethyl-3-hexanol, 2-ethyl-4-methylpentanol, and 4-octanol, has been measured between dodecane and water. Measurements were made at alcohol concentrations in the dodecane of less than 0.1 mol/dm3, and as a function of temperature from 10 °C to 35 °C. From these distribution data, standard thermodynamic functions for transfer were calculated. Standard Gibbs energies of transfer from water to dodecane at 25 °C were in the range −14.1 to −15.1 kJ/mol, whereas the standard enthalpies of transfer at 25 °C varied from 29 to 39 kJ/mol. Thus, the change in the standard enthalpy tends to inhibit transfer, but a large standard entropy of transfer results in dodecane being the favoured phase.

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