Mixtures of solvents. Understanding the preferential solvation model

The equilibrium position is mainly dictated by solvent polarity however, there is clearly a specific contribution of solvent acidity from the carbonyl groups of the dione. 10.3.7.3 Mixtures of solvents. Understanding the preferential solvation model 

The solvation of a solute, wheflier ionic or neutral, in a mixture of solvents is even more complex than in a pure solvent This is assumed to be so largely because a solvent mixture 

Preferential solvation has been studied in the light of various methods, most of which are based on conductance and transference measurements , NMR measurements of the chemical shift of a nucleus in the solute or measurements of the solvatochromism of a solute in the IR or UV-Vis spectral region. Plots of the data obtained from such measurements against the composition of the bulk solvent (usually as a mole fraction) depart clearly from the ideal behavior and the deviation is ascribed to the presence of preferential solvation. 

Several reported methods aim to quantify preferential solvation none, however, provides an acceptable characterization facilitating a clear understanding of the phenomenon. 

If preferential solvation is so strongly dictated by the polar or ionic character of the solute, then characterizing a mixture of solvents by using a molecular probe will be utterly impossible since any conclusions reached could only be extrapolated to solutes of identical nature as regards not only polarity and charge, but also molecular size and shape. 

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Mixtures of solvents. Understanding the preferential solvation model... 

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