Comparative Ultrasonic and Acoustic Properties of Ethylbenzoate with Secondary and Tertiary Butanol Binary Mixtures

This work reports on the ultrasonic velocity, density, viscosity, and derived acoustic parameters of binary mixtures of ethylbenzoate with 2-butanol and 2-methyl-2-propanol over a range of compositions at 303.15 K, 308.15 K, 313.15 K, and 318.15 K. The experimental measurements were used to calculate adiabatic compressibility, intermolecular free length, internal pressure, and acoustic impedance to elucidate underlying molecular interactions. For both systems, increasing ethylbenzoate mole fraction produced higher velocity and density, and lower viscosity and compressibility, indicating enhanced structural ordering. The ethylbenzoate + 2-butanol system exhibited stronger cohesive interactions, as revealed by higher ultrasonic velocities, acoustic impedance and internal pressure compared to the ethylbenzoate + 2-methyl-2-propanol system, attributed to reduced steric hindrance and more effective hydrogen bonding in the former. Temperature elevation weakened interactions in both mixtures, consistent with increased thermal agitation. These findings are significant for designing solvent systems in chemical processing and provide fundamental insights into mixture behavior relevant to industrial and environmental applications.