An investigation into the relationship between molecular structure and rich/lean loading of linear amine-based CO2 absorbents

Gas sweetening or acid gas removal is conventionally used in various applications and industries since there is a worldwide concern about global warming. Amine-based solvents play an important role in acid gas removal processes. It seems that in the future the application of amines is more considerable due to the identification of newly developed amine-based absorbents. Numerous studies of amines have shown evidence that some relationships exist between the structure of amine and its capacity for carbon dioxide absorption. Quantitative Structure Property/Activity Relationship (QSPR/QSAR) provides an effective method for predicting amines capacity for CO2 absorption. In this paper, first, density functional theory (DFT) method level of B3LYP and 6-311+g (d,p) basis set was employed to complete molecular geometrical optimization. Then, GA-MLR (multiple linear regression-genetic algorithms) was applied for model development. The accuracy of the models was verified by different statistical tests. Based on the results, it could be concluded that a linear amine-based solvent with the most primary amine groups and the least secondary amine groups seems to be the most suitable industrial amine as it increase the cyclic or effective capacity. The aim of this study is to provide a better understanding toward the effect of molecular structure of amine-based solvent on its CO2 absorption and desorption capacities, simultaneously.