Volumetric and acoustic properties of binary solutions of water and acetonitrile at 298.15K, 303.15K, 308.15K, 313.15K, 318.15K, and 323.15K

To get a deep insight into the interactions between water (W) and acetonitrile (ACN), and to provide new data, three types of physical properties such as volumetric, transport, and acoustic properties of their binary solutions at different compositions in the whole range of concentration and at six different temperatures (298.15 K, 303.15 K, 308.15 K, 313.15 K, 318.15 K, and 323.15 K) at 0.1 MPa atmospheric pressure have been studied. Here, densities (ρ), viscosities (ƞ), and speeds of sound (u) were measured experimentally, and using these data some other important properties such as excess molar volumes, V_m^E, apparent molar volumes, Φ_v, thermal expansibilities, α, excess thermal expansibilities, α^E, excess viscosities, η^E, relaxation times, τ, deviation in speeds of sound, ∆u, acoustic impedances, Z, deviation in acoustic impedances, ∆Z, Rao's constants, R, free volumes, V_f, and excess free volumes, V_f^E, were calculated. The experimental and their derived properties were fitted to appropriate polynomial equations. Analysis of the results indicates a significant interstitial accommodation of free molecules of one component into the structural network of the other, mainly at the water-rich region in the water - acetonitrile system.