Abstract
In this paper, we calculate solvation free energies of several compounds in ionic liquids. These free energies
are used to compute properties such as Henry’s law constants and activity coefficients, generally required
in the design of environmentally sustainable processes. It is known, for instance, that carbon dioxide from
combustion is one of the main sources of anthropogenic greenhouse gases. Recently, the propensity of the
ionic liquid [emim][B(CN)4] for the physisorption of CO2 has been reported, which makes it a potential
solvent for carbon capture. In the present work, molecular dynamics simulations of the solvation of CO2
in ionic liquids [emim][B(CN)4] and [emim][NTf2] are carried out both at infinite dilution and at high
concentrations. A systematic study is performed by comparing several force fields and assessing the efficacy
of simplification measures such as rigid-body dynamics and pairwise electrostatics. Our results confirm
recent experimental observations that, for a given volume of solvent, lower pressure is required to absorb a
certain amount of CO2 in [emim][B(CN)4] than in other ionic liquids.