Solvation of ions. XXV. Partial molal volumes of single ions in protic and dipolar aprotic solvents

1975 ◽  
Vol 28 (5) ◽  
pp. 955 ◽  
Author(s):  
MRJ Dack ◽  
KJ Bird ◽  
AJ Parker

Partial molal volumes at 25� are reported for some 1 : 1 electrolytes, and for triphenylmethane, in dimethyl sulphoxide, N,N- dimethylformamide, acetonitrile, propylene carbonate, formamide and hexamethylphosphoramide. The assumption that ΔV�tr(Ph4As+) = ΔV�tr(BPh4-) was used to obtain ionic partial molal volumes of transfer from water to the non-aqueous solvents. Solvent compressibility appears to determine the partial molal volumes of non-electrolytes and large hydrophobic ions in solution. Values of ΔV�tr for cations and anions are discussed in terms of ion-solvent interactions, solvent-solvent interactions and steric crowding of large solvent molecules around the ions.

1985 ◽  
Vol 50 (11) ◽  
pp. 2493-2508 ◽  
Author(s):  
Petr Kyselka ◽  
Zdeněk Havlas ◽  
Ivo Sláma

Solvation of Li+, Be2+, Na+, Mg2+, and Al3+ ions has been studied in binary mixtures with dimethyl sulphoxide, dimethylformamide, acetonitrile and water, and in ternary mixtures of the organic solvents with water. The CNDO/2 quantum chemical method was used to calculate the energies of solvation, molecular structures and charge distributions for the complexes acetonitrile...ion (1:1, 2:1, 4:1), dimethyl sulphoxide...ion (1:1), dimethylformamide...ion (1:1), and acetonitrile (dimethyl sulphoxide, dimethylformamide)...ion...water (1:1:1).


1983 ◽  
Vol 36 (9) ◽  
pp. 1675 ◽  
Author(s):  
P Singh ◽  
ID MacLeod ◽  
AJ Parker

The partial molal volumes of Na+, Ag+, Cu+, Ph4As+, BPh4-, Cl- and NO3- are reported for transfer from water to various acetonitrile/water (MeCN/H2O) mixtures by using the tatb assumption that ΔVt(Ph4As+) = ΔVt(BPh4-). The results, which show a complex dependence of ionic partial molal volumes on MeCN/H2O solvent composition, are discussed in terms of ion-solvent and solvent-solvent interactions. This study complements earlier work on the energetics of transfer (tatb assumption) of these ions from water to aqueous acetonitrile solutions.


1974 ◽  
Vol 27 (3) ◽  
pp. 477 ◽  
Author(s):  
BG Cox ◽  
GR Hedwig ◽  
AJ Parker ◽  
DW Watts

Standard molar free energies, enthalpies and entropies of transfer of some uni-univalent electrolytes from water to methanol, N-methylformamide, formamide, dimethyl sulphoxide, N,N-dimethyl- formamide, propylene carbonate, sulpholane, N-methylpyrrolidone and acetonitrile are presented. They have been divided into the corresponding thermodynamic properties for single ions by means of extrathermodynamic assumptions. Changes in the chemistry of anions on transfer from protic to dipolar aprotic solvents are mainly a function of enthalpy changes. There is a substantial loss of entropy on transferring both anions and cations from water to non-aqueous solvents. Entropies of transfer can be interpreted in terms of ordering and disordering solvent molecules and a uniquely extensive water structure. Evidence for solvation of the first and second kind in water is presented. Enthalpies of transfer from water are exothermic for cations but endothermic for many anions.


1966 ◽  
Vol 19 (1) ◽  
pp. 43 ◽  
Author(s):  
WA Millen ◽  
DW Watts

Ion association constants at 30� have been determined for the cis-[Co en, Cl2]+Cl- ion pair in NN-dimethylformamide (DMF), NN-dimethylacetamide (DMA), and at 20.0�, 25.0�, and 30.0� in dimethyl sulphoxide (DMSO), by a spectrophotometric method. Association constants for the cis-[Co en2 Cl2]+Br- and the trans- [Co en2 Cl2]+Cl- ion pairs have also been determined in DMF at 30�.


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