Solubility and Spectral Investigation of Dilute SO2 in the Binary System Polyethylene Glycol 600 + Water and System’s Density, Viscosity, and Surface Tension

Isothermal gas-liquid equilibrium (GLE) data were measured for dilute SO 2 in the binary system polyethylene glycol 600 (PEG) + H 2 O at T = 298.15 K and p = 122.66 kPa, in which SO 2 partial pressures were calculated in the range of (0 to 140) Pa. Based on the fitting GLE data, Henry’s law constants ( H x ) of dilute SO 2 in various PEG (1) + H 2 O (2) mixtures were obtained. Meanwhile, densities, viscosities, and surface tension of the binary system PEG (1) + H 2 O (2) were also measured over the whole concentration range at T = (298.15 to 323.15) K. From density and viscosity data, the excess molar volumes ( V m E ) and viscosity deviations (Δ η ) were calculated. Based on kinematic viscosity data, the enthalpy of activation for viscous flow (Δ H *) and entropy of activation (Δ S *) for the viscous flow were also obtained. Additionally, the important intermolecular interaction among PEG, H 2 O and SO 2 were investigated using UV-Vis, FTIR, and 1 H NMR spectroscopic techniques. Spectral results showed that the interaction between PEG and H 2 O resulted from hydrogen bonding , and the interaction of PEG with SO 2 resulted from both the O   →   S charge-transfer interaction and intermolecular hydrogen bonding.