Hydrophobic and hydrophilic interactions in binary mixtures of alpha-picoline with water

The ultrasound velocity in and the density of aqueous solutions of alpha-picoline were measured in the whole concentration range and within the temperature limits 293-298 K. The viscosity of the solutions was measured at 293 K. The molar compressibility, molar volume and the corresponding excesses and partial functions as well as the coefficients of adiabatic compressibility and the excess Gibbs energy of viscous flow were calculated. The results are discussed in terms of hydrophobic and hydrophilic interactions. In dilute solutions of picoline the hydrophobic Hydration leads to a structure resembling that of the solid clathrate II, while at higher concentrations the hydrophobic association and hydrophilic hydration becomes more pronounced.