Preferential solvation in mixed solvents. Part 8. Aqueous methanol from sub-ambient to elevated temperatures

The inversed Kirkwood-Buff integral method is applied to mixtures of water and methanol from - 13 to 250 °C. Preferential solvation is deduced from these integrals and shown over the entire composition and temperature ranges. The self-preference of water increases with rising temperatures in both water- and methanol-rich mixtures, reaching a limiting value near the critical point of methanol. At the equimolar composition, though, this self- preference reaches a shallow maximum near 150 °C. The methanol self- preference in methanol-rich mixtures is slight, but this hydrophobic effect is considerable at 15 mol% of methanol, reaching a pronounced maximum near 150 °C. The effect of the methanol on the structure of the water, the incorporation of water into the structure of methanol, and their changes with increasing temperatures are discussed.