Thermodynamic properties and spectral investigation of dilute sulfur dioxide in binary system N,N-dimethylformamide + diethylene glycol

In this work, isothermal gas–liquid equilibrium (GLE) data were measured for dilute SO2 in the binary system N,N-dimethylformamide (DMF) (1) + diethylene glycol (DEG) (2) at T = (298.15, 303.15, 313.15, and 318.15) K and p = 122.66 kPa. Based on the GLE data, Henry’s law constants were obtained by fitting the linear slope of GLE data, and the thermodynamic parameters were calculated. The thermodynamic results showed that the dissolving processes of dilute SO2 in the binary system are spontaneous, enthalpy driving, and reversible behavior. When conventional UV, FT-IR, and 1H NMR spectroscopic techniques were used for inspection of spectral changes of dilute SO2 in the binary system DMF (1) + DEG (2), the spectral results suggest that hydrogen bonding and interaction of carbonyl oxygen atoms in DMF with hydroxyl hydrogen atoms in DEG were formed as HCO⋯HOCH2CH2OCH2CH2OH⋯, and the strong absorption capability of SO2 in the binary system can be due to the intermolecular S⋯O interaction as the formation HCO⋯(O)SO.