title: Local environment structure and dynamics of CO2in the 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide and related ionic liquids.
abstract: Despite the innumerous papers regarding the study of the ionic liquids as a potential candidate for CO2capture, many details concerning the structure and dynamics of CO2in the system are still to be revealed, i.e., the correlation between the local environment structure and the dynamic properties of the substance. This present work relied on the performance of molecular dynamics both for the neat [C2mim][Tf2N] and [C2mim][Tf2N]/CO2mixtures in an attempt to elucidate the local environment of CO2and their effects on the dynamic properties of [C2mim][Tf2N]. A slight change in the orientation of the cation and anion could be observed, which was correlated to the cation and anion moving away from each other in order to receive the carbon dioxide. The gas molecules pushed both the cation and the anion away to create sufficient void to its accommodation. The diffusion coefficient of [C2mim]+is higher than [Tf2N]-regardless the increase of the CO2concentration. The addition of CO2in the ionic liquid has shown an increase of 4-5 times for the diffusivity of ions, which was related to the decrease of cation-anion interaction strength. The transport properties' results showed that the addition of CO2in the ionic liquid generates the fluidization of the system, decreasing the viscosity as a consequence of the local environment structure changing. Likewise, the effect of the type of anion and cation on the system properties was studied considering [Ac]-and [BMpyr]+ions, showing large effects by the change of anion to [Ac]-which rise from the strong [C2mim]+-[Ac]-interaction, which conditions the solvation of ions by CO2molecules.
authors.affiliation: Instituto de Química, Universidade Federal de Alfenas, Rua Gabriel Monteiro da Silva 700, CEP, 37130-000 Alfenas, MG, Brazil.
authors.forename: Tuanan C
authors.initials: TC
authors.lastname: Lourenço
authors.affiliation: Department of Chemistry, University of Burgos, 09001 Burgos, Spain.
authors.forename: Santiago
authors.initials: S
authors.lastname: Aparicio
authors.affiliation: Instituto de Química, Universidade Federal de Alfenas, Rua Gabriel Monteiro da Silva 700, CEP, 37130-000 Alfenas, MG, Brazil.
authors.forename: Gabriela C
authors.initials: GC
authors.lastname: Costa
authors.affiliation: Instituto de Química - Departamento de Físico-Química, Universidade Federal Fluminense, Outeiro de São João Batista s/n CEP, 24020-150 Niterói, RJ, Brazil.
authors.forename: Luciano T
authors.initials: LT
authors.lastname: Costa