Sound Velocities in Aqueous Solutions of n-Butylamine between 303.15 and 323.15 K: Experiment and Theory

Abstract

Density (ρ) and sound velocity (u) have been measured for aqueous solutions of n-butylamine ( W + NBA) in the whole range of composition at an interval of 5 K. Deviation in Sound Velocity (∆u), Isentropic Compressibility (Ks), Excess Isentropic Compressibility (KsE), Specific Acoustic Impedance (Z), Rao's Constant (R) and Wada's Constant (W) have been calculated from measured u and ρ. ∆u versus x2 curve is negative and with the increment of temperature, ∆u decreases; Ks values of W + NBA are all positive whereas KsE values are all negative. All the above outcomes are interpreted in terms of molecular interaction especially hydrogen bonding and hydrophobic hydration between water and n-butylamine. Moreover, experimental data for u correlated with some theoretical equations. The relations are Nomoto’s Relation (uN), Impedance Relation (uIR), the Rao’s specific velocity method relation (uR), Van Deel’s ideal mixing relation (uIMR) and theoretical sound velocity according to Free Length Theory (uFLT). The validity of these relations with experimental values has been tested by measuring standard percentage deviation () and average percentage error (APE).