Handbook of Solvents - George Wypych - ChemTech - Ventech!

542 Y. Y. Fialkov, V. L. Chumak
Figure 9.12. Dependence of concentration (in molar parts) of solvate forms Li(EDA) mS n on molar fraction, x B,of
the second component in the binary solvents ethylenediamine-DMSO (a) and ethylenediamine-DMFA (b): 1m=4,
n=0;2- m=n=2;4-m=0, n=4.
aminophthalimide was 30%. Resolvation process completes at n-butanol concentration in
solution ≈90%.
Mishustin 37 proposed a strict and accurate method for selective solvation study. The
method is based on data of free energy transfer of electrolyte from individual solvent A to
mixed solventA-B.Themethod takes into account non-ideality of the system, and allows
calculation of the concentration of different solvate forms and their dependence on the
mixed solvent composition.
An example of application of this method is in the work. 39 Authors have calculated relative
concentration of different solvate forms of Li + in the mixed solvent ethylenediamine -
DMSO and ethylenediamine-DMFA (Figure 9.12). Free energy of lithium transfer from
DMSO (DMFA) in the mixed solvent has been calculated from the time of spin-lattice relaxation
of kernel 7 Li. The curves presented in Figure 9.12 depict quantitatively the selectivity
of Li + relative to ethylenediamine, which is more basic component in contrast to the
second components of the mixed solvent, namely DMSO and DMFA.
The following systems can serve as examples of the effect of composition of the mixed
solvent on the solvate shell composition:
[Cr(NH) S(H 2O) m(DMSO) n] 3+ -H 2O - DMSO 40
[Be(H 2O) m(EG) n]SO 4 -H 2O - ethylene glycol 41
[Be(H 2O) m(HMPTA) n]SO 4 -H 2O - HMPTA 42
[Ni(H 2O) mS n]ClO 4 -H 2O - S (where S is methanol, ethanol, propanol, DMSO) 43
Data presented in Figure 9.13 contain information on the composition of solvate shell
as a function of molar fraction of water in the mixed solvent H 2O-other solvents. 43
Monograph 44 contains collection of data on resolvation constants of the ions in the mixed
solvents.
The above presented dependencies of the composition of solvate shell on the mixed
solvent composition as well as resolvation constants permit calculation of the solvate composition
by varying solvent composition. The dependence of resolvation constants on the
permittivity of the solvent is discussed in the example of the proton resolvation process.