Volumetric and spectroscopic properties of binary liquid mixtures of isopentyl alcohol with butylamine at T = (288.15–333.15) K

Highlights: • Densities were measured for the IPA (1) + BA (2) mixed system from 288.15 to 333.15 K. • Excess molar volumes for the IPA (1) + BA (2) liquid mixture were derived. • Apparent, partial and excess partial molar volumes values were computed. • Strong intermolecular interactions (H-bonding) were determined. • The formation of new H-bonds was discussed by spectral analysis. The current article presents the experimental density (ρ) values reported as a function of mole fraction for the binary liquid mixtures of isopentyl alcohol (IPA) + butylamine (BA) at the temperatures T = (288.15 to 333.15) K with 5 K intervals under atmospheric pressure (0.1 MPa). Based on experimental data, the molar volume ($V_m$), excess molar volume ($V_m^E$), apparent molar volumes ($V_{m,\varnothing ,1}$and $V_{m,\varnothing ,2}$), partial molar volumes (${\stackrel{-}{V}}_{m,1}$and ${\stackrel{-}{V}}_{m,2}$), and excess partial molar volumes (${\stackrel{-}{V}}_{m,1}^E$ and ${\stackrel{-}{V}}_{m,2}^E)$ values were computed over the complete mole fraction range. Also, at infinite dilution, the values of partial molar volumes (${\overline{V}}_{m,1}^{°}$ and ${\overline{V}}_{m,2}^{°}$), and excess partial molar volumes (${\overline{V}}_{m,1}^{°\text{E}}$ and ${\overline{V}}_{m,2}^{°\text{E}}$) of the isopentyl alcohol and butylamine were calculated. The calculated $V_m^E$ values were correlated to the Redlich-Kister (R-K) model. Further, the excess molar volume was theoretically described by using Prigogine-Flory-Patterson (PFP) theory at the above temperatures. The obtained excess molar volume shows negative deviations from the ideal behaviour and becomes more negative at a higher temperature. From the above said parameters results, the H-bonding and acid-base interactions in the unlike molecules was determined. Additionally, the existence of new H-bonding interaction between IPA and BA molecules was further confirmed using ¹H NMR and FT-IR spectroscopic studies.