Investigation of molecular interactions in binary mixture (benzyl benzoate + ethyl acetate) at T = (308.15, 313.15, and 318.15) K: An insight from ultrasonic speed of sound and density

Speed of sound (u) and densities (ρ) of binary liquid mixtures of benzyl benzoate with ethyl acetate, including pure liquids, over the entire composition range have been measured at T = (308.15, 313.15 and 318.15) Kusing the experimental data such as excess molar volume (V_m^E), excess acoustic impedance (Z^E), excess intermolecular free length (L_f^E), excess available volume (V_a^E), excess surface tension (σ_s^E), excess coefficient of thermal expansion (α_P^E), excess isotropic compressibility, (k_T^E), excess internal pressure (πiE) and excess free volume (V_f^E). Also enthalpy (H^E), entropy (S^E), Gibb's free energy (G^E), partial molar volumes/partial molar compressibilities, excess partial molar volumes/excess partial molar compressibilities, partial and excess partial molar volume of the components at infinite dilution (V∞m,∞, V∞m,2∞), (V∞m,1E,∞ and V∞m,2E,∞) and variations of H^E/S^E/G^E with change in pressure at constant temperature have been evaluated. Molecular interactions in the system have been studied in the light of variation of excess values of calculated properties and these properties have been fitted to Redlich-Kister type polynomial equation. Further, Lennard-Jones potential repulsive exponent term (n) and relative association (R_A) are computed and interpreted to elucidate the molecular interactions in the liquid mixture. The present investigation also comprises evaluation of the acoustic non-linearity parameter (B/A) in the mixtures and calculation of cohesive energy Δ A, Van der Wall's constants (a, b) and distance of the closest approach (d). Moreover, speed of sound in the mixtures has been evaluated using various semi-empirical relations and such values were compared with experimental speeds to verify applicability to the systems investigated. The computational study allows a qualitative analysis of the results in terms of the individual contribution to the excess enthalpy and Gibb's energy in terms of electrostatic, van der Waals and hydrogen bonding interaction in the binary mixture.