title: Density functional theory study on carbon dioxide absorption into aqueous solutions of 2-amino-2-methyl-1-propanol using a continuum solvation model.
abstract: We used density functional theory (DFT) calculations with the latest continuum solvation model (SMD/IEF-PCM) to determine the mechanism of CO(2) absorption into aqueous solutions of 2-amino-2-methyl-1-propanol (AMP). Possible absorption process reactions were investigated by transition-state optimization and intrinsic reaction coordinate (IRC) calculations in the aqueous solution at the SMD/IEF-PCM/B3LYP/6-31G(d) and SMD/IEF-PCM/B3LYP/6-311++G(d,p) levels of theory to determine the absorption pathways. We show that the carbamate anion forms by a two-step reaction via a zwitterion intermediate, and this occurs faster than the formation of the bicarbonate anion. However, we also predict that the carbamate readily decomposes by a reverse reaction rather than by hydrolysis. As a result, the final product is dominated by the thermodynamically stable bicarbonate anion that forms from AMP, H(2)O, and CO(2) in a single-step termolecular reaction.
authors.affiliation: Chemical Research Group, Research Institute of Innovative Technology for the Earth, 9-2 Kizugawadai, Kizugawa, Kyoto 619-0292, Japan. hyamada@rite.or.jp
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Yamada
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Matsuzaki
authors.forename: Takayuki
authors.initials: T
authors.lastname: Higashii
authors.forename: Shingo
authors.initials: S
authors.lastname: Kazama
mesh_terms: D002245:Carbon Dioxide / Q000737:chemistry*; D011412:Propanolamines / Q000737:chemistry*; D011789:Quantum Theory; D012995:Solubility; D012996:Solutions; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
chemical_list: D011412:Propanolamines; D012996:Solutions; D014867:Water; D002245:Carbon Dioxide; C006551:2-amino-2-methyl-1-propanol