Excess Properties and Intermolecular Interaction of Three Butanol Isomers+1,2-Propanediamine Binary Systems

To investigate intermolecular interactions between three different structures of butanol (n-butanol, 2-butanol, or iso-butanol) and 1,2-propanediamine (1,2-PDA), the density (rho) and viscosity (eta) of these butanol isomers + 1,2-PDA binary systems were determined in the temperature range of 298.15-318.15 K at a pressure of 100.5 kPa. Based on these data, the activation thermodynamic parameters and excess properties, including excess molar volume (V-m(E)), partial molar volume (V), apparent molar volume (V-phi), coefficient of thermal expansion (a(p)), viscosity deviation (Delta eta), activation enthalpy change (Delta H*), activation entropy change (Delta S*), Gibbs energy of activation of viscous flow (Delta G*), and the excess Gibbs energy of activation of viscous flow activation Gibbs energy (Delta G(*E)) were systemically calculated. Subsequently, the influence of test temperatures on the physical characteristics of the binary systems was thoroughly investigated. Several semiempirical models were used to match the experimental density and viscosity values, and the values of V-m(E), Delta eta, and Delta G(*E) were calculated using the Redlich-Kistre equation. The intermolecular hydrogen bonds (HBs) in the three binary systems were analyzed by Raman and ultraviolet spectroscopy. Finally, the form of HBs and the van der Waals effects in the butanol isomer + 1,2-PDA binary systems were confirmed through computational studies.