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›› 2011, Vol. 11 ›› Issue (4): 652-659.

• 系统与集成 • 上一篇    下一篇

Molecular Simulation on Microstructure of Ionic Liquids in Capture of CO2

岳振国 刘晓敏 赵玉灵 张晓春 吕兴梅 张锁江   

  1. 过程所多相室 过程所多相室 过程所多相室 中国科学院过程工程研究所 中国科学院过程工程研究所
  • 收稿日期:2011-06-07 修回日期:2011-06-13 出版日期:2011-08-20 发布日期:2011-08-20
  • 通讯作者: 岳振国

Molecular Simulation on Microstructure of Ionic Liquids in Capture of CO2

YUE Zhen-guo LIU Xiao-min ZHAO Yu-ling ZHANG Xiao-chun LU Xing-mei ZHANG Suo-jiang   

  1. State Key Laboratory of Multiphase Complex System, Institute of Process Engineering, Chinese Academy of Sciences State Key Laboratory of Multiphase Complex System, Institute of Process Engineering, Chinese Academy of Sciences State Key Laboratory of Multiphase Complex System, Institute of Process Engineering, Chinese Academy of Sciences State Key Laboratory of Multiphase Complex System, Institute of Process Engineering, Chinese Academy of Sciences Institute of Process Engineering, Chinese Academy of Sciences Institute of Process Engineering, CAS
  • Received:2011-06-07 Revised:2011-06-13 Online:2011-08-20 Published:2011-08-20
  • Contact: YUE Zhen-guo

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摘要： Molecular dynamic simulation is used to study the microstructure of four kinds of ionic liquids (ILs), [Emim]PF6, [Emim][Tf2N], [PC6,6,6,14]PF6 and [PC6,6,6,14][Tf2N] in the capture process of CO2. Radial distribution function (RDF) and spatial distribution function (SDF) are used to analyze the microscopic properties of these systems. The calculated results show that the space distribution of CO2 around ILs determines the capability of ionic liquids for capturing CO2. Based on the analysis of SDF, CO2 and PF6- are overlapped partially around [Emim]+ in [Emim]PF6-CO2 mixture. When the anion is [Tf2N]-, cations are mainly distributed on one side of [Tf2N]- near N atom, and CO2 is concentrated on two sides near the fluoroalkylgroup (?CF3), and there is little overlapped district between cation and CO2. In [PC6,6,6,14]PF6-CO2 mixture, layered structure is found and CO2 is much nearer to PF6- than [PC6,6,6,14]+. Based on the analysis of RDF, in the phosphonium-based ILs, the highest distribution densities of anions and CO2 around cations are about 6 and 3 times as their average ones respectively, while in the imidazolium-based ILs, they are about 3 and 2 respectively, this means that the distributions of CO2 and anions around the imidazolium-based ILs are more evenly distributed than those around the phosphonium-based ILs.

关键词: ionic liquid, molecular dynamics simulation, CO2, capture, microstructure

Abstract: Molecular dynamic simulation is used to study the microstructure of four kinds of ionic liquids (ILs), [Emim]PF6, [Emim][Tf2N], [PC6,6,6,14]PF6 and [PC6,6,6,14][Tf2N] in the capture process of CO2. Radial distribution function (RDF) and spatial distribution function (SDF) are used to analyze the microscopic properties of these systems. The calculated results show that the space distribution of CO2 around ILs determines the capability of ionic liquids for capturing CO2. Based on the analysis of SDF, CO2 and PF6- are overlapped partially around [Emim]+ in [Emim]PF6-CO2 mixture. When the anion is [Tf2N]-, cations are mainly distributed on one side of [Tf2N]- near N atom, and CO2 is concentrated on two sides near the fluoroalkylgroup (?CF3), and there is little overlapped district between cation and CO2. In [PC6,6,6,14]PF6-CO2 mixture, layered structure is found and CO2 is much nearer to PF6- than [PC6,6,6,14]+. Based on the analysis of RDF, in the phosphonium-based ILs, the highest distribution densities of anions and CO2 around cations are about 6 and 3 times as their average ones respectively, while in the imidazolium-based ILs, they are about 3 and 2 respectively, this means that the distributions of CO2 and anions around the imidazolium-based ILs are more evenly distributed than those around the phosphonium-based ILs.

Key words: ionic liquid, molecular dynamics simulation, CO2, capture, microstructure

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