Studies of osmotic coefficients and volumetric behaviour on aqueous solutions of β-cyclodextrin at 298.15 K

Abstract

2073-2080The osmotic coefficient, solute activity coefficients and apparent molar volume are determined for β-cyclodextrin (β -CD ) using the techniques of vapor pressure osmometry and digital densitometer in aqueous solutions (0.00164 to 0.01308 mol kg-1) at 298.15 K. The thermodynamic data of activities and partial molar volumes for solvent and solute are computed using appropriate methodology and equations. Theories of dilute solutions such as McMillan-Mayer and Flory-Huggins are applied to estimate the second virial coefficient (B*2) for β-CD, the number of binding sites and χ12 interaction parameter. Using the partial molar volume data at infinite dilution and B*2 value, the contribution due to solute-solvent and solute-solute interactions in terms of attractive and repulsive components are estimated. The values of B*2 and the components are compared with the values reported for mono-saccharides, disaccharides and other non-electrolytes. The results are discussed in terms of hydrophobic hydration and hydrophobic interaction