Thermophysical Properties and Barker–Henderson Perturbation Modeling of 2-(Dimethylamino)ethanol + 1-Alkanol (C5–C10) Mixtures

Densities and viscosities of binary mixtures comprising 2-(dimethylamino)ethanol (DMAE) and a homologous series of 1-alkanols (1-pentanol to 1-decanol) were investigated to elucidate their molecular interactions and non-ideal thermophysical behavior. The derived properties, including excess molar volumes (VE) and viscosity deviations (Δη), exhibit positive and negative deviations from ideality, respectively. The magnitudes of both VE and Δη increase systematically with the elongation of the alkyl chain, indicating that the disruption of the alcohol’s self-associated hydrogen-bonded networks and steric hindrance dominate over specific cross-interactions. Furthermore, the Barker–Henderson (BH) perturbation theory was successfully applied to model the volumetric behavior of these complex mixtures. The BH framework demonstrated reasonable accuracy in predicting mixture densities, yielding average absolute deviations (AAD) ranging from 0.033