Computational investigation of reactive to nonreactive capture of carbon dioxide by oxygen-containing Lewis bases

Recent work has shown that room temperature ionic liquid systems reactively absorb CO₂ and offer distinct advantages over current CO₂ capture technologies. Here we computationally evaluated CO₂ interaction energies with a series of oxygen-containing Lewis base anions (including cyclohexanolate and phenolate and their respective derivatives). Our results show that the interaction energy can be tuned across a range from reactive to nonreactive (or physical) interactions. We evaluated different levels of theory as well as possible corrections to the interaction energy, and we explained our calculated trends on the basis of properties of the individual anions. We found that the interaction energy between CO₂ and the Lewis bases examined here correlates most strongly with the atomic charge on the oxygen atom. This insight provides a useful handle to tune the anion-CO ₂ interaction energy for future experimental and computational studies of novel CO₂ capture systems.