Density, Refractive Index, and Sound Velocity for the Binary Mixtures of Tri-n-Butyl Phosphate and n-Butanol between 303.15 K and 323.15 K

Density, ρ, refractive index, n D, and sound velocity, u, have been measured for pure TBP, n -BuOH, and their binary mixtures in the range, 0 ≤ x 2 ≤ 1, between (303.15 and 323.15) K at an interval of 5 K. From measured ρ and n D, excess molar volumes, V m E, thermal expansivity, α, excess thermal expansivity, α E, and deviation in refractive index, Δ n D, were calculated. Furthermore, using ρ and u, some derived properties, such as acoustic impedance, z, isentropic compressibility, κ s, and their deviations (Δ u, Δ z, and Δκ s ), were also calculated. Values of ρ, n D, u, z, and κ s were found to correlate with concentration dependent polynomials, whereas the deviations/excess properties were fitted well to Redlich–Kister equations. The variation patterns of the studied properties were discussed with reference to the nature of molecular interactions taking place between the liquids of TBP and n -BuOH.