Solubilities and thermodynamic properties of SO2 in five biobased solvents

• The SO2 solubility in five biobased solvents (BBSs) has been reported.
• The experimental data were reduced to Henry’s law constants.
• The standard dissolution Gibbs free energy, enthalpy and entropy changes were calculated.
• The solubilities of SO2 and thermodynamic properties of dissolution in BBSs, ILs and other molecular solvents were compared.

Five biobased solvents (BBSs) with high boil point, namely ethyl levulinate (EL), butyl levulinate (BL), dibutyl succinate (DBS), gamma-butyrolactone (GBL) and gamma-valerolactone (GVL), were applied in absorption of SO2. The solubilities of SO2 in the BBSs were determined at temperatures (293.15 to 333.15) K and pressures (0 to 120) kPa. Henry’s constant and thermodynamic properties (standard dissolution Gibbs energy, dissolution enthalpy, dissolution entropy) were further calculated according to the solubility data. The gravimetric solubilities in BBSs changed with the sequence of GBL > GVL > EL > BL > DBS. The solubility of SO2 and absorption enthalpy in present BBSs and other molecular solvents as well as ionic liquids (ILs) were systemically compared. The results illustrated that GBL and GVL possessed the potentiality to capture SO2 among all absorbents due to their relatively large solubility and low absorption enthalpy for SO2, biodegradability, low toxicity, inexpensive cost and low viscosity.