ABSTRACT This study investigated the molecular interactions within mixtures of n-butylamine (NBA) and isomers of propanol. We conducted an exhaustive analysis of excess molar volume ( V m E ), deviation in ultrasonic speed ( Δ u ), and excess isentropic compressibility ( κ s E ) by utilising the measured data of density ( ρ ) and ultrasonic speed ( u ) at T = 298.15 K to 318.15 K under pressure at 0.1 MPa. This led to the derivation of secondary properties such as partial ( V ˉ i ), excess partial ( V ˉ iE ), and apparent molar volume ( V φi ). As the temperature rises, the V m E become more negative, while the Δu values more positive. The RK equation was employed to fit the excess properties data, with further exploration through additional theories. The findings presented here offer vital insights into amine – alcohol mixtures and their thermodynamic and acoustic properties, which are invaluable for optimising related chemical engineering and industrial processes.