THERMODYNAMIC STUDIES ON WATER-BETA-CYCLODEXTRIN-SURFACTANT TERNARY-SYSTEMS

Conductance measurements are reported for double chain surfactants lik e N,N,N-octylpentyldimethylammonium (OPAC) and N,N,N-octyloctyldimethy lammonium chlorides (OOAC) in water-beta-cyclodextrin solution. From t he specific conductivity data, the apparent critical micelle concentra tion (cmc) and the degree of counterion dissociation (beta) were obta ined at a fixed beta-CD concentration (m(beta CD) = 0.01190 mol kg(-1) ), besides from the cmc value and that in water (cmc) the stoichiomet ry of the surfactant-beta-CD complex was calculated. Densities, heat c apacities, enthalpies of dilution at 298 K and osmotic coefficients at 310 K were measured for the same systems; the apparent molar volumes, V-phi, and heat capacities, C-phi, of two surfactants in beta-CD solu tion, calculated as functions of surfactant concentrations m(s), have made possible to obtain the properties of transfer of the surfactant f rom water to beta-CD-water solutions.