Solubility and thermodynamic properties of SO2 in three low volatile urea derivatives

The solubilities of SO 2 in three dipolar aprotic urea diversities, 1,1,3,3-tetramethylurea (TMU), 1,3-dimethyl-2-imidazolidinone (DMI), and 1,3-dimethyl-3,4,5,6-tetrahydro-2 (1H)-pyrimidinone (DMPU) was measured at temperatures ranging from (293.15 to 323.15)   K and pressure up to 120   kPa. By correlating the solubility results with a reaction equilibrium thermodynamic model (RETM), Henry’s constants ( H m ), reaction equilibrium constants ( K °), and enthalpy (Δ H r ) in the absorption process were obtained. The results indicate that the three solvents exhibit both strong physical and weak chemical interactions with SO 2 . Further comparison of the capture performance with ILs, deep eutectic solvents (DESs), and several organic solvents, DMI, DMPU and TMU are noted to be excellent absorbents for acidic SO 2 .