Handbook of Solvents - George Wypych - ChemTech - Ventech!

552 Y. Y. Fialkov, V. L. Chumak
Figure 9.17. Dependence of K a of sulfuric acid on 1/ε in
mixed solvents based on DMSO at 298.15K.
fractions of components of the mixed solvent x A and x B:
B A
B ( a a)
[ 1 ( a ( 1 add B( 1 i ) ) ) ]
adduct, K i; and resolvation constant, K us,
(e.g., equilibrium constant of process
HA n�A+B↔HA n�B + A), and with molar
B
K = K + K −K − K / + K x + K
[9.109]
a a
Figure 9.18. Dependence of K a for HSO 3F on solvent
composition in mixed solvents: A - n-butanol at
298.15K. 7 B:1-n-hexane; 2 - nitrobenzene; 3 - methanol;
4 - N,N- dimethyl aniline.
The equation [9.109] changes into equation [9.100] when both components of the
mixed solvent have donor character, e.i., Kus = 0. The analysis of equation [9.100] 59 shows
that the solvate active property of components of the mixed solvent A-B have to be changed
to influence the dependence of Ka on composition of the mixed solvent. Some examples of
such influence are presented in Figure 9.18.
9.4.6 SOLVENT EFFECT ON EXCHANGE INTERACTION PROCESSES
Chemical processes of exchange interaction, given by equation:
EF+ HL ↔ EL+HF [9.110]
are common in research and technology, but the solvent effect on their equilibrium was not
frequently studied. Let us systematize the existing experimental data on these processes. 60
Systems with non-associated reagents
The process of exchange interaction between bis-(carbomethoxymethyl)mercury and mercury
cyanide
(CH 3OCOCH 2) 2Hg + Hg(CN) 2 ↔ 2CH 3OCOCH 2HgCN [9.111]
has been studied in the mixed solvent DMSO-pyridine. The components of solvent possess
almost equal ability to specific solvation of mercury-organic compounds. This ability is