Density, viscosity, excess properties, and intermolecular interaction of propylene glycol methyl ether + 1,2-propylenediamine binary system

Abstract

In this work, the systematic measurements of physicochemical properties, viz., density (ρ) and viscosity (η) values of propylene glycol methyl ether (PGME) + 1,2-propylenediamine (1,2-PDA) binary system, including pure substances, over the entire mole fraction range at the temperatures of T/K = (298.15 to 318.15) under atmospheric pressure of P = 100.5 kPa. The fundamental data were used to calculate several excess properties, including excess molar volume (VmE), viscosity deviation (Δη), and excess activation Gibbs free energy (ΔG∗E). Meanwhile, the work further investigated the values of thermal expansion coefficient (αp), partial molar volume (V¯) and apparent molar volume (Vφ), thereby offering a comprehensive understanding on non-ideal behavior of the binary system. Furthermore, the variations in ρ values with various molar ratios and temperatures were evaluated through Jouyban-Acree model and nonlinear least squares method. Simultaneously, Grunberg-Nissan model, Eyring-Margules model, Heric model, and McAllister model, were used to fit the dependence of η values on the molar ratio. Arrhenius equation was employed to fit the temperature dependency of η values. In addition, Redlich-Kister (R-K) equation was utilized to fit the VmE, Δη, and ΔG∗E values of binary system. Based on spectral analyses of Raman, ultra-violet (UV), and 1H Nuclear Magnetic Resonance (NMR) and density functional theory (DFT) calculation, the intermolecular hydrogen bond (IHB) of PGME with 1,2-PDA was discussed in depth.