title: Supported absorption of CO2 by tetrabutylphosphonium amino acid ionic liquids.
abstract: A new type of "task specific ionic liquid", tetrabutylphosphonium amino acid [P(C4)4][AA], was synthesized by the reaction of tetrabutylphosphonium hydroxide [P(C4)4][OH] with amino acids, including glycine, L-alanine, L-beta-alanine, L-serine, and L-lysine. The liquids produced were characterized by NMR, IR spectroscopies, and elemental analysis, and their thermal decomposition temperature, glass transition temperature, electrical conductivity, density, and viscosity were recorded in detail. The [P(C4)4][AA] supported on porous silica gel effected fast and reversible CO2 absorption when compared with bubbling CO2 into the bulk of the ionic liquid. No changes in absorption capacity and kinetics were found after four cycles of absorption/desorption. The CO2 absorption capacity at equilibrium was 50 mol % of the ionic liquids. In the presence of water (1 wt %), the ionic liquids could absorb equimolar amounts of CO2. The CO2 absorption mechanisms of the ionic liquids with and without water were different.
authors.affiliation: Research Laboratory of Green Chemical Engineering and Technology, Institute of Process Engineering, Chinese Academy of Sciences, PO Box 353, Beijing 100080, P. R. China.
authors.forename: Jianmin
authors.initials: J
authors.lastname: Zhang
authors.forename: Suojiang
authors.initials: S
authors.lastname: Zhang
authors.forename: Kun
authors.initials: K
authors.lastname: Dong
authors.forename: Yanqiang
authors.initials: Y
authors.lastname: Zhang
authors.forename: Youqing
authors.initials: Y
authors.lastname: Shen
authors.forename: Xingmei
authors.initials: X
authors.lastname: Lv