Volumetric manifestation of van der Waals interactions between cholesterol and organic solvents of linear structure

The densities of solution of cholesterol in several selected n-alkanes, alkan-1-ols and tertiary amines have been measured at 298.15 K. The values of standard partial molar volume of cholesterol have been calculated and the effect of solute–solvent and solvent–solvent interactions on the partial molar volume of cholesterol have been discussed. The increase in the alkyl chain length (Ri) of solvents such as alkanes and amines enhances the dispersion solvent–solvent interactions (per –CH2–) and weakens the contribution of dispersion forces in the cholesterol-solvent interactions. Both these effects bring about an increase in the partial molar volume of cholesterol with increasing the alkyl chain length of solvent molecules. In alcohols, the cholesterol–solvent dispersion interactions increase with Ri. This effect may be accounted for by the self-association of the solvent. In consequence, there is no distinct dependence of partial molar volume of cholesterol on the alkyl chain length of alcohol.