Excess properties and intermolecular interactions of 2-methoxyethanol + ethylenediamine binary system: Density, viscosity, spectral analyses, computational chemistry, and CO2 absorption property

Abstract

To examine the fundamental physicochemical properties as well as intermolecular interactions for the 2-methoxyethanol (EGME) (1) + ethylenediamine (EDA) (2) binary system, this work systemically measured the density ($\rho$) and viscosity ($\eta$) values of the binary system with various mole ratios at P = 100.5 kPa and T = (298.15–318.15) K with the growth gap of 5 K. The as-measured values of the pure substances were compared with literature data. Multiple semi-empirical formulas were used to fit $\rho$ and η values, and the absolute average deviations (AAD%) were calculated. After that, the excess molar volume (${\text{V}}_{\text{m}}^{\text{E}}$), partial molar volume ($\overline{V}$), apparent molar volume (${\text{V}}_{\phi }$), viscosity deviation ($\Delta \text{η}$), excess activation of Gibbs free energy ($\Delta G^{\ast E}$), and several thermodynamic properties of the binary system were systemically analyzed. According to analysis results, it has been proven that the interaction exists between EGME and EDA molecules. And then, excess properties were fitted to the Redlich-Kister equation using multi-parametric nonlinear regression analyses, and standard deviations ($\sigma$) were calculated. In addition, based on various characterization methods including Raman, ultraviolet (UV), and nuclear magnetic resonance hydrogen (¹H NMR) spectral analyses and density functional theory (DFT) calculation results, it is demonstrated that there is intermolecular hydrogen bonds in EGME (1) + EDA (2) binary system as the form of –OH⋯NH₂–, which was consistent with the existence forms of intermolecular hydrogen bonds in different alcohol-amine systems from references. Finally, CO₂ absorption capacity by pure EDA, pure EGME, and the EGME (1) + EDA (2) binary system were severally determined.