Preferential Solvation of P-nitroaniline in Alcohol-dioxan Binary Solvent Mixture

The Preferential solvation of p-nitroaniline (PNA) has been investigated by monitoring the intramolecular charge transfer band in different alcohol-dioxan binary solvent mixtures. The plots of observed spectroscopic transition energy vs. mole fraction confirm the presence of preferential solvation in the mixtures. In the higher mole fraction of alcohol PNA is preferentially solvated by dioxan while in the higher mole fraction of dioxan it is preferentially solvated by alcohol. This type of preferential solvation has been explained by hydrogen bonding between PNA and the solvent molecules. Besides hydrogen bonding, hydrophobicity of the alcohols is also an important factor during the solvation process