title: Ditetraalkylammonium amino acid ionic liquids as CO₂ absorbents of high capacity.
abstract: By grafting butyl or ethyl onto tetramethylethylenediamine, quaternary ammonium salts with two positive charge centers were formed at the first step. Metathesis with Ag(2)O followed. Through neutralization with glycine, l-alanine, or valine, a series of new ditetraalkylammonium amino acid ionic liquids (DILs) for CO(2) capture were generated. The structures of DILs, as shown in Figure 1, were verified by using (1)H NMR and EA. These DILs were found to be of quite high viscosity which militated against their industrial application in CO(2) removal. Drawing on the experience of mixed amines' aqueous solutions, these DILs were blended with water or N-methyldiethanolamine (MDEA) aqueous solutions to act as special absorbents of CO(2). Using a Double-Tank Absorption System, the absorption performance of these DIL solutions was investigated in detail. The experimental results indicated that among the three aqueous solutions of DILs (20%, 40%, and 80 wt %), the solution of 40% DIL had a higher absorption rate of CO(2) than the other two, demonstrating the different effects of concentration and viscosity on the absorption. The solution of 40% DIL or the 15% DIL + 15% MDEA had much higher capacity for CO(2) than the corresponding monocation tetraalkylammonium AAILs, due to the special structure of the dication which could influence the solubility of CO(2) in the aqueous solution.
authors: State Key Laboratory of Pollution Control & Resource Reuse, School of Chemistry and Chemical Engineering, School of the Environment, Nanjing University, Nanjing 210093, China.
authors: Jing-Wen
authors: JW
authors: Ma
authors: Zheng
authors: Z
authors: Zhou
authors: Feng
authors: F
authors: Zhang
authors: Cheng-Gang
authors: CG
authors: Fang
authors: You-Ting
authors: YT
authors: Wu
authors: Zhi-Bing
authors: ZB
authors: Zhang
authors: Ai-Min
authors: AM
authors: Li
mesh_terms: D000327:Adsorption; D000397:Air Pollution / Q000517:prevention & control; D002245:Carbon Dioxide / Q000032:analysis / Q000737:chemistry*; D052918:Environmental Restoration and Remediation; D052578:Ionic Liquids / Q000737:chemistry*; D008956:Models, Chemical; D015394:Molecular Structure; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
chemical_list: D052578:Ionic Liquids; D000644:Quaternary Ammonium Compounds; D014874:Water Pollutants, Chemical; D002245:Carbon Dioxide