Force field of the TMGL ionic liquid and the solubility of SO2 and CO2 in the TMGL from molecular dynamics simulation

An all-atom force field is developed using a combination of density functional theory calculations and OPLS force field parameter values for the 1,1,3,3-tetramethylguanidium lactate (TMG) lactic acid (LAC) ionic liquid (TMGL). The computed density of the TMGL is in good agreement with available experimental values. The internal energy components, cohesive energy density, and the self-diffusion constants are also discussed. Molecular dynamics simulations are then conducted to investigate the solubility of the SO2 and CO2 gases in the TMGL. The simulation results show strong organization Of SO2 about the TMG cation and the LAC anion, especially the LAC anion, but relatively weak organization Of CO2 about the cation and the anion of the TMGL, which explained well the selectivity of the TMGL toward the SO2 and CO2.