Solute-solvent and solvent-solvent interactions in binary solvent mixtures. Part 7. Comparison of the enhancement of the water structure in alcohol-water mixtures measured by solvatochromic indicators

Abstract

A preferential solvation model that takes into account the enhancement of the structure of water when small amounts of alcohol are added was applied to solvatochromic data for binary mixtures of water with 2-methylpropan-2-ol, propan-2-ol, ethanol and methanol. Application of the model allows the calculation of the effect of the enhancement of the water structure on solvatochromic solvent properties. It is demonstrated that the enhancement of water structure increases the solvent dipolarity/polarizability and hydrogen-bond donor acidity and decreases the solvent hydrogen-bond acceptor basicity. The effect decreases in the order 2-methylpropan-2-ol–water, propan-2-ol–water, ethanol–water and methanol–water. © 1998 John Wiley & Sons, Ltd.