title: CO2-Selective Absorbents in Air: Reverse Lipid Bilayer Structure Forming Neutral Carbamic Acid in Water without Hydration.
abstract: Emission gas and air contain not only CO2but also plentiful moisture, making it difficult to achieve selective CO2absorption without hydration. To generate absorbed CO2(wet CO2) under heating, the need for external energy to release the absorbed water has been among the most serious problems in the fields of carbon dioxide capture and storage (CCS) and direct air capture (DAC). We found that the introduction of the hydrophobic phenyl group into alkylamines of CO2absorbents improved the absorption selectivity between CO2and water. Furthermore, ortho-, meta-, and para-xylylenediamines (OXDA, MXDA, PXDA, respectively) absorbed only CO2in air without any hydration. Notably, MXDA·CO2was formed as an anhydrous carbamic acid even in water, presumably because it was covered with hydrophobic phenyl groups, which induces a reverse lipid bilayer structure. Dry CO2was obtained from heating MXDA·CO2at 103-120 °C, which was revealed to involve chemically the Grignard reaction to form the resulting carboxylic acids in high yields.
authors.affiliation: Division of Pharmaceutical Sciences, Graduate School of Medical Sciences, Kanazawa University , Kakuma-machi, Kanazawa 920-1192, Japan.
authors.forename: Fuyuhiko
authors.identifier: 0000-0003-2999-083X
authors.initials: F
authors.lastname: Inagaki
authors.affiliation: Division of Pharmaceutical Sciences, Graduate School of Medical Sciences, Kanazawa University , Kakuma-machi, Kanazawa 920-1192, Japan.
authors.forename: Chiaki
authors.initials: C
authors.lastname: Matsumoto
authors.affiliation: Division of Pharmaceutical Sciences, Graduate School of Medical Sciences, Kanazawa University , Kakuma-machi, Kanazawa 920-1192, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Iwata
authors.affiliation: Division of Pharmaceutical Sciences, Graduate School of Medical Sciences, Kanazawa University , Kakuma-machi, Kanazawa 920-1192, Japan.
authors.forename: Chisato
authors.identifier: 0000-0001-8621-1068
authors.initials: C
authors.lastname: Mukai
mesh_terms: D065966:Absorption, Physicochemical; D000388:Air; D000588:Amines / Q000737:chemistry; D002219:Carbamates / Q000737:chemistry*; D002245:Carbon Dioxide / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D008051:Lipid Bilayers / Q000737:chemistry*; D015394:Molecular Structure; D014867:Water / Q000737:chemistry*
chemical_list: D000588:Amines; D002219:Carbamates; D008051:Lipid Bilayers; D014867:Water; D002245:Carbon Dioxide; C070766:carbamic acid