Volumetric and refractive index properties of isobutyric acid - water binary mixtures at temperatures ranging from 300.15 to 313.15Â K

Refractive index deviations Δn, excess molar volumes VE, and molar refractions R of isobutyric acid + water binary mixtures have been calculated from experimental data of refractive index and densities over the whole composition range at temperatures ranging from 300.15 K to 313.15 K under atmospheric pressure. The Δn and VE results were correlated using the fourth-order Redlich-Kister polynomial equation with the maximum likelihood principle being applied for the determination of adjustable parameters. These quantities have been discussed in terms of intermolecular interactions between the components of the mixtures.