Volumetric, FT-IR, and optical properties of 2–amino-1-butanol with isomeric butanol at 298.15 K–318.15 K using PFP theory and graph theoretical approach

The density and optical properties of binary mixtures containing 2–amino 1–butanol (2AB) and isomeric butanol were measured over a temperature range (298.15–318.15) K and 0.1 MPa pressure. Using these measurements, excess molar volume (${V_m}^E$) and deviation in refractive index ($\Delta n_D$) were computed. The negative ${V_m}^E$values, at equimolar composition, follow the order: tert-butanol > sec-butanol > isobutanol > n-butanol, while the $\Delta n_D$ exhibit the opposite trend. The Prigogine–Flory–Patterson theory and the Graph theoretical approach were applied to interpret the ${V_m}^E$ data at 298.15 K, respectively. Moreover, the molecular species of various components are predicted to exist in both pure and mixed states by the GTA. Furthermore, FT–IR spectroscopy confirmed the formation of hydrogen bonding between the molecules of the components. The ${V_m}^E$ values decrease with increasing temperature, while the $\Delta n_D$ values increase with increasing temperature. Various mixing rules were applied to calculate $n_D$ theoretically. This study aims to expand the database of thermophysical properties for amine-alcohol mixtures, providing a reference for engineers and scientists developing advanced CO₂ capture technologies.