Measurement of density, viscosity and surface tension of tri-ethylene glycol + 1,3-propanediamine mixtures & their computational chemistry and spectral analysis

For liquid and liquid mixtures, density (ρ), viscosity (η) and surface tension (γ) are seen as important basic data. This research reported the data of ρ, η and γ for the binary mixture of tri-ethylene glycol (TEG) + 1,3-propanediamine (PDA) at p  = .1 MPa and T  = (293.15 to 318.15) K within the whole molar fraction range, finding the maximum of η and γ values when the mole fraction of TEG was x 1  ≈ 0.65. After that, excess molar volume ( V m E ), viscosity deviation (Δη), and surface tension deviation (Δγ) were carefully calculated, and the minimum V m E values and the maximum Δγ values were obtained when the molar fraction of TEG was at x 1  ≈ 0.50; however, the maximum Δη values shifted from x 1  ≈ 0.60 to x 1  ≈ 0.66. And then, the Redlich-Kister (R-K) equation fitting was performed on above parameters to evaluate the coefficient and standard deviation, apparent molar volumes ( V φ , 1 and V φ , 2 ) and partial molar volumes ( V 1 ¯ $\overline{V_1}$ and V 2 ¯ $\overline{V_2}$ ). Meanwhile, Gaussian 09 software was used to further analyze the intermolecular force and to calculate the dissociation energy and bond length of the mixture, and the interaction of PDA with TEG were discussed on the basis of FTIR, UV–Vis and FLS spectral technologies. The results showed that there were hydrogen-bond interactions between the nitrogen atoms in PDA and the hydroxyl hydrogen atoms in TEG.