Molar Volumes of Ethoxylated Nonylphenols in Micellar Solutions

Density rho and apparent molar volume V-phi are determined in aqueous micellar solutions of ethoxylated nonylphenol (ENP) mixtures. The ratio Delta rho/c of the excess solution density Delta rho and the molar concentration c lays the foundation of a model, which satisfactorily reproduces Delta rho and V-phi of the mixtures; predicts these quantities for known composition mixtures; and allows estimation of the partial molar volumes V-i of the components and the volume V-mix of mixing.