Experiment and simulation study of CO2 solubility in dimethyl carbonate, 1-octyl-3-methylimidazolium tetrafluoroborate and their mixtures

CO2 capture with solvent-based process is known as a promising technology for controlling the global warming. In this work, the constant-volume method was used to investigate CO2 solubility in DMC, ionic liquid of [Omim][BF4], and their mixtures from 298.15 to 328.15 K under pressures up to about 3 MPa. The COSMO-RS model was used to predict the Henry's constants and the vapor pressures of DMC in the mixtures. The experimental results showed the CO2 solubility in [Omim][BF4] is higher than DMC at 318.15-328.15 K and adding [Omim][BF4] into DMC can decrease the viscosity compared to the pure [Omim][BF4]. Besides, the COSMO-RS simulation results showed the Henry's constants in the mixtures increases with the decreasing mass ratio of [Omim][BF4] which are consistent with experimental values and the vapor pressures of DMC in the mixtures decreases with the increasing mass ratio of [Omim][BF4]. Moreover, the activation energy (Ea) predicted from viscosity showed the higher viscosity mean the larger Ea and the larger Ea indicate the higher CO2 solubility in these solvents. Finally, the mixtures of DMC and [Omim][BF4] may be used as promising physical solvents to capture CO2 with high partial pressures, which combine the advantages of organic solvents and ionic liquids.