Ion Transfer into Solvent Mixtures

The transfer of ions from a sonrce solvent into a binary solvent mixture has been studied mainly for the cases where water is the source solvent and also one of the components of the solvent mixtures, that is, aqueous solvent mixtures. Few studies are available in which ions are transferred from nonaqueous solvents and into completely nonaqueous mixtures. The source solvent in some of these studies, according to reports by Kondo et al., Cox and Waghome, Marcus, and Piekarski et al., was methanol [1-6], in other studies acetonitrile [7, 8], and some further systems were also studied [2, 5, 9]. 

In many cases, there exists enthalpy-entropy compensation and relatively small values of A G (r ,W- W-i-S) may result from much larger values of A /f (r ,W- W-i-S) and rA,j5 (l, W- W-i-S). Therefore, it is not advisable to use this path for the estimation of Gibbs energies of transfer for such ions and aqueous solvent compositions that are not available in in Refs. 10 and 11 from data in Ref. 13. On the contrary, if both A, G °(I, W W-i-S) and 

Values in parentheses are neither recommended nor tentatively recommended as specified in these sources. Ph P rather than Ph As.  

Few direct reports on the standard molar heat capacities and volumes of transfer of electrolytes and ions from a source solvent to a solvent mixture are available. Examples are found for transfer from water to aqueous I-butanol [14] and aqueous acetonitrile [15] in the smdies by Hefter et al. Since, however, the standard molar heat capacities and volumes of ions in water are known (Sections 2.3.1.1 and 2.3.1.5) and the corresponding values in aqueous cosolvent mixtures are also known (Section 6.2.1 below), the data for the transfer, if needed, can be readily calculated from these sources. 

---