Abstract
Partial molar volumes of hydrophobic solutes such as alkylbenzenes, naphthalene, etc. in water estimated from high-pressure solubility have been reviewed. We found positive volume changes (∆hhV) for the hydrophobic hydration though only negative ones have been observed for a long time since Kauzmann (1959), and also found that the ∆hhV increases changing the sign from negative to positive as a rotational diameter of the solutes increases from methylene group (0.50 nm) to anthracene (0.67 nm). Another feature for the hydrophobic hydration is negative isothermal compressibility of the partial molar volume of hydrophobic solutes in water. But we found it is positive for naphthalene, anthracene, etc. in water. These results make us see the hydrophobic hydration in perspective. High-pressure solubility is an useful method to estimate the partial molar volume for insoluble solutes, e.g., naphthalene in water, for which a vibrating-tube densitometer is useless.
https://ror.org/0197nmd03 
