Molecular force field for alcanolamines
Résumé
Aqueous solutions of amines are commonly used in post-combustion carbon dioxide capture processes. The dissolution of the gas in aqueous solutions depends on the molecular interactions in {water+amine+CO2} systems. Molecular simulation is a promising tool for predicting thermodynamic properties and establishing structure-propertie relationships essential to the development of predictive models. The main objective of this work is to develop a molecular force field adapted to describe interactions and conformations of alcanolamines containing the N-C-C-O backbone. Monoethanolamine (MEA) is the simplest amine containing this structure. It is also the reference absorbent for CO2 capture processes [1]. We propose a methodology to determine the parameters needed for the molecular simulation of such amines. This methodology will be first tested for pure amines and then applied to aqueous solutions. In both situations, the amines are considered in a polar solvation environment, dominated by hydrogen bonding interactions. Thus, polarization effects were taken into account by calculating the electrostatic charge distributions in presence of solvent molecules. The densities and vaporization enthalpies of pure amines were calculated by molecular simulation and compared to experimental values.