Estudo computacional das interações intermoleculares de líquidos iônicos derivados do cátion imidazólio com potencial de captura de CO2

Abstract

Ionic liquids play a range of applications, with CO2 capture being one of them. Such applications have motivated several studies with the goal of elucidate the behavior of its properties. Ionic liquids based on imidazolium cation have characteristics that aid in the CO2 capture process, which in turn are related to their intermolecular interactions. The objective of this work is to understand how the different substitutions in imidazolium cation affect its intermolecular forces and assist in the capture of CO2. Molecular dynamics calculations were performed for 14 ionic liquids based on imidazolium cation. The balanced structures had a coefficient of determination value of 0.97 with the experimental density. RDF, SDF and MSD calculations were performed in the system structure containing 200 pairs of ionic fluid. After the analysis of the molecular trajectories of these structures, the representative structures of the system were taken and calculations of NCI and DFT were performed. The equilibrium distance between cation and anion remained the same in general. The interactions between cation and anion were primarily around the imidazolium ring. Cations with alkyl chains between 2 and 4 carbons showed a more diffuse behavior and the cations functionalized, less diffuse. Van der Waals interactions proved to be important for the formation of the ionic pair cluster and interaction free energy proved to be an important driver in the formation of the ionic pair.