Among the several strategies that have been proposed for CO2 capture, one of the most promising approaches is the use of ionic liquids, which consist of systems entirely composed of ions, but with low melting points (<100oC). Beyond the fact that such liquids possess negligible vapor pressures, their main advantage is the possibility to tune properties accordingly to a specific application. In particular, their utilization in the CO2 capture has two main approaches, the physical and the chemical absorption. The former explores the CO2 selectivity over other gases, whereas the latter comprises the functionalization of cations and/or anions with groups that react with CO2. However, in some cases, as in imidazolic ionic liquids formed by acetate anions, the presence of CO2 induces the formation of carbenes, promoting the chemical absorption. In such cases, the gas capture depends on the subtle balance between the physisorption and chemisorption. This project aims to evaluate the main factors that govern both processes, in order to understand how the presence of neutral molecules, as CO2, induces the formation of reactive species as carbenes. To accomplish that, it will be performed solubility measurements as function of pressure and temperature in several ionic liquids, what allows the determination of the thermodynamic parameters of absorption. The processes of physisorption and chemisorption will be characterized by spectroscopic measurements (Raman, IR and NMR), as well as physical properties measurements (density, viscosity and diffusion coefficients), whose results will be supported by theoretical calculations (DFT and MD).
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