This paper attempts to describe the types and nature of interactions present in binarymixtures containing valeric acid and 1-alkanols (1-pentanol up to 1-decanol) using theoretical and experimental methods. The density and viscosity of the mixtures above were measured at temperatures of 293.15 K to 323.15 K. Values of excess molar volumes (Vm E ) and viscosity deviations(Δη) were calculated. The findings indicate that strong interactions occur in binary solutions containing short-range 1-alkanol, and increasing the length of the alcohol chain causes a weakening of intermolecular interactions. To confirm the experimental results, the conductor-like screening model for real solutions (COSMO-RS) method was used to calculate the activity coefficients of the compounds in the liquid mixtures and the contact probability (CP) of alcohols with the valeric acid. Then, the D parameter, the concentration-concentration structure factor (SCC(0)), and the chemical short-range order parameter (α') were obtained and used to describe the existing interactions for binary mixtures. For binary systems, viscosity and density data are novel and have not previously been reported
