Solubilities and Thermodynamic Properties of Carbon Dioxide in Some Biobased Solvents

Using the isochoric saturation method, solubilities of CO2 in five biobased solvents (BBSs) have been determined at temperatures between 293.15 and 323.15 K with 10 K intervals and pressure scope of (0–600.0) kPa. The BBSs were selected from glyceryl triacetate (GT), glycerol formal (GF), dl-1,2-isopropyli-deneglycerol (GAK), triethyl citrate (TEC), and acetyl triethyl citrate (ATEC). Henry’s constants and thermodynamic properties such as Gibbs free energy, enthalpy, and entropy of dissolution were derived from the solubility data. The gravimetric solubilities of CO2 in BBSs changed with the sequence of GT > ATEC > TEC ≈ GAK > GF. All the dissolution enthalpies were negative at each condition. The dissolution capacities of BBSs for CO2 were further compared with those of several common absorbents as well as ionic liquids. It was shown that they were similar to polyethylene glycol dimethyl ether (NHD) which is an industrial CO2 absorbent.