SOLVENT EFFECTS ON CHEMICAL PROCESSES .7. QUANTITATIVE DESCRIPTION OFTHE COMPOSITION DEPENDENCE OF THE SOLVENT POLARITY MEASURE E(T)(30) IN BINARY AQUEOUS-ORGANIC SOLVENT MIXTURES
Rd. Skwierczynski et Ka. Connors, SOLVENT EFFECTS ON CHEMICAL PROCESSES .7. QUANTITATIVE DESCRIPTION OFTHE COMPOSITION DEPENDENCE OF THE SOLVENT POLARITY MEASURE E(T)(30) IN BINARY AQUEOUS-ORGANIC SOLVENT MIXTURES, Perkin transactions. 2, (3), 1994, pp. 467-472
The solvation effect component of the phenomenological model of solven
t effects is applied to E(T)(30), the molar transition energy of the D
imroth-Reichardt betaine, In binary aqueous-organic solvents. The depe
ndence of E(T)(30) on x(2), the mole fraction of organic cosolvent, ca
n be quantitatively described for all 17 systems studied. New data are
given for 9 of these systems. It is found that a 1-parameter model su
ffices to describe the composition dependence of the highly polar coso
lvents, whereas a 2-parameter model is needed to account for other cos
olvents, which yield a nonhyperbolic composition dependence. The solva
tion parameters, which are exchange equilibrium constants, yield corre
lations suggesting their positive dependence on cosolvent hydrophobici
ty and electron-pair donor ability.