离子液体吸收CO2的分子模拟学研究
文献类型：学位论文
| 作者 | 岳振国 |
| 学位类别 | 硕士 |
| 答辩日期 | 2011-05-24 |
| 授予单位 | 中国科学院研究生院 |
| 导师 | 吕兴梅 ; 张锁江 |
| 关键词 | 离子液体 分子动力学 低粘度离子液体 二氧化碳吸收 |
| 其他题名 | Molecular Simulation of CO2 Capture with Ionic Liquids |
| 学位专业 | 化学工艺 |
| 中文摘要 | 离子液体作为新型的绿色溶剂具有广阔的应用前景。近年来有许多关于离子液体应用的报道，研究表明离子液体将是最具潜力的CO2吸收剂之一。应用离子液体吸收CO2已经成为国际研究的热点。计算机模拟作为研究分子性质和结构有效的手段，被广泛应用于研究离子液体体系微观结构及宏观性质。本文通过分子模拟方法对离子液体吸收CO2 的微观机理做了详细的研究。涉及咪唑类与季膦类离子液体吸收CO2 的比较研究，离子液体在常温高压下与不同比例CO2 混合后的微观特性的研究，和几类新型低粘度离子液体吸收CO2 的微观性质的研究。论文的主要研究内容和结果如下：（1）选取了两种常见的咪唑类离子液体[Emim]PF6 和[Emim][Tf2N]，和两种季磷类离子液体[PC6,6,6,14]PF6 和[PC6,6,6,14][Tf2N]，采用分子动力学模拟方法，对这4类离子液体吸收CO2 的微观性质进行了详细的分析和比较，发现离子液体在吸收CO2 过程中阴离子对吸收能力的影响较大；相同模拟条件下，同种阴离子在同体积的范围内咪唑类离子液体能容纳的CO2 较季磷类离子液体多，CO2 在季磷类离子液体周围的分布区域较窄，分布密度比同类咪唑类离子液体高。（2）在常温高压的条件下，选取[Emim]PF6 和CO2 以7:1、7:3和1:1的不同混合比例来进行模拟研究，研究表明随着CO2 摩尔浓度比的升高，离子液体的阴阳离子间距稍微变大，最明显的是阴离子与阴离子之间的距离变大，[Emim]PF6 吸收CO2 是物理吸收过程，主要靠阴阳离子间的挪移来容纳更多CO2。（3）选取了4种新型的低粘度离子液体，[PC2,2,2,5]PF6，[PC2,2,2,5][Tf2N]，[PC2,2,2,(1O1)]PF6 和[PC2,2,2,(1O1)][Tf2N]。首先基于AMBER 系统建立了[PC2,2,2,5]+ 和[PC2,2,2,(1O1)]+ 的分子力场，在此基础上对它们分别进行了分子动力学模拟，通过分析径向分布函数和空间分布函数，发现[PC2,2,2,(1O1)]+ 吸收CO2 能力优于阳离子[PC2,2,2,5]+，这是由于CO2 在[PC2,2,2,(1O1)]+ 周围的分布更加分散。 |
| 英文摘要 | Ionic liquids, as a new kind of environment-friendly solvents, have exhibited great vigour and wide application prospects. Over the past decade, numerous studies have been made into the use of ionic liquids and found that it may be one of the most hopeful solvent to capture CO2. Capture CO2 with ionic liquids has been an international hot spot. At the same time, theoretic researches on capture CO2 are becoming more and more important. As one of the most effective means to study molecular properties and structures, Computer simulation is an effective way to study the microcosmic structures and the macro properties of ionic liquids. In this work, molecular simulation method is used to study the microstructure of CO2 capture with ionic liquids, including comparing the similarities and differences of imidazolium-base and phosphonium-base ionic liquids when they capturing CO2, the microscopic properties of ionic liquids capturing different proportion of CO2 under high pressure, and a research of the microscopic properties of low viscosity ionic liquids capturing CO2. The details are listed as follows: (1) Two kinds of imidazolium-based ILs and two kinds of phosphonium-based ILs were selected, including [Emim]PF6, [Emim][Tf2N], [PC6,6,6,14]PF6 and[PC6 6,6,14][Tf2N]. Molecular dynamic simulations were used to study the micro-structures of these ILs capturing CO2. I found that anions play the most important role in the process of ILs capturing CO2. With the same anion, imidazolium-base ILs will capture more CO2 than phosphonium-based ILs in the same volume and the distribution of CO2 is more concentrated in phosphonium-based ILs. (2) Under the room temperature and high pressure, I selected three different mixing proportion of [Emim]PF6 and CO2, including 7:1, 7:3 and 1:1. The research shows that the distance of ions will become longer when the mole fraction of CO2 incerased and the most obvious change is the distance between anion and anion. The process of [Emim]PF6 capturing CO2 is a physical process and the movement of anion made the IL capture more CO2. (3) Four kinds of low-viscosity ILs are selected, including [PC2,2,2,5]PF6, [PC2,2,2,5][Tf2N], [PC2,2,2,(1O1)]PF6 and [PC2,2,2,(1O1)][Tf2N]. Molecular simulation method has been used. I found that with the same anion, [PC2,2,2, (1O1)]+ can capture more CO2 than [PC2,2,2,5]+, and [PC2,2,2, (1O1)]+ may made the distribution of CO2 more concentrated around ILs. |
| 语种 | 中文 |
| 公开日期 | 2013-09-24 |
| 页码 | 93 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/1728]  |
| 专题 | 过程工程研究所_研究所（批量导入） |
| 推荐引用方式 GB/T 7714 | 岳振国. 离子液体吸收CO2的分子模拟学研究[D]. 中国科学院研究生院. 2011. |
入库方式： OAI收割
来源：过程工程研究所
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