Densities and excess molar volumes of methanol, ethanol and n-Propanol in pure water and in water plus surf excel solutions at different temperatures

Densities, rho of the systems Methanol, Ethanol and n-Propanol in water and in 0.05 and 0.1% Surf Excel (SE) solutions in water were measured at temperatures from 303.15 to 323.15 K covering the whole composition range. Excess molar volumes, V-m(E) for the systems were found to be negative and large in magnitude. Densities and excess molar volumes have been plotted against mole fraction of the solutes (X-2). All these properties have been expressed satisfactorily by appropriate polynomials. No appreciable change of the densities and excess molar volumes were observed by the addition of surfactant (0.05 and 0.1%) to the studied systems. An explanation of V-m(E) in terms of hydrophobic hydration and hydrophilic effect of the solutes is offered.