Mechanism of the Absorption of CO2 in Ionic Liquid Dimer

The density functional theory (DFT) calculations with the modern continuum solvation model (IEFPCM-SMD) was used to study the mechanism of CO2 absorption at room temperature using ionic liquid such as, [EMIM][BF4] (1-ethyl-3-methylimidazolium tetrafluoroborate) monomer and dimer ionic liquid [IL] dimer comprises two couple of anions and cations, so that more intermolecular interactions are established than in the single IL pair. In this paper, we determined the minimum energy structures and to determine the possible binding sites for CO2 absorption in [EMIM][BF4] monmer and dimer; by comparing the relative minimum energy of [EMIM][BF4] in the presence and in absence of CO2. It was found that CO2 is stabilized by the multiple interactions with several anions. When CO2 penetrates the IL monomer or dimer, through gas-to-liquid diffusion, the O-C-O (CO2)-BF4 intermolecular bond is likely to be formed immediately and bind the CO2 molecule. This result suggests that ionic liquid dimer is suitable for the absorption of CO2. Asiat. Soc. Bangladesh, Sci. 45(1): 137-144, June 2019