Temperature Dependent Thermo-Acoustical Properties of Diethyl Ether + 1-Hexanol at 298–313 K: A Comparative Experimental Investigation

Abstract

Acomprehensive thermo-acoustical investigation of diethyl ether and 1-hexanol has been carried out at four different temperatures (298, 303, 308, and 313 K). Experimentally measured parameters include density (ρ), viscosity (η), and ultrasonic velocity (U). Using experimental data, various derived thermo-acoustical parameters such as acoustic impedance (Z), intermolecular free length (L_f), internal pressure (π_i), Wada’s constant (W), molar enthalpy, and inverse relaxation time (1/τ) were evaluated. Further, excess properties including excess molar volume (\(V_{{\text{m}}}^{{\text{E}}}\)), excess acoustic impedance (Z^E), excess ultrasonic velocity (U^E), excess viscosity (η^E), and excess intermolecular free length (\(L_{{\text{f}}}^{{\text{E}}}\)) were calculated to analyze deviations from ideal behavior and intermolecular interactions. Temperature dependence reveals systematic variation of cohesive forces with increasing temperature. Strong associative hydrogen bonding in 1-hexanol leads to higher viscosity, lower molar volume and higher acoustic impedance compared to diethyl ether, which predominantly exhibits dipole–dipole and dispersive interactions. The sign and magnitude of excess parameters indicate the strength and nature of molecular interactions and structural rearrangements within the liquid systems. The present study provides valuable thermodynamic data for molecular interaction analysis and industrial process modeling.