Volumetric, Optical, and Spectroscopic Properties of Three Binary Mixtures of An Amine and Alcohols

The density data over a spectrum of temperatures, including 293.15, 298.15, 303.15, 308.15, 313.15, and 318.15 K, and refractive indices at 293.15 K for butylamine binary combinations with ethanol, 1-propanol, or 2-propanol under standard atmospheric pressure conditions were established. Various parameters were then calculated at infinite dilution, including excess, partial and apparent molar volumes as well as the excess partial molar volumes. The excess molar volumes were fitted applying the Redlich–Kister equation, permitting the estimation of differences between calculated and experimental values. Our results consistently demonstrated that the values deviated negatively from the optimal behavior of the binary systems, which was attributed to dipole-dipole interactions, hydrogen bond formation, and structural effects. We also conducted refractive index measurements and corroborated our findings with Fourier-transform infrared spectroscopy.