Interpretation of CO2 solubility and selectivity in nitrile-functionalized room-temperature ionic liquids using a group contribution approach
Interpretation of CO2 solubility and selectivity in nitrile-functionalized room-temperature ionic liquids using a group contribution approach
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DOI：
10.1021/ie8001217
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发表时间：
2008-09-17
影响因子：
4.2
通讯作者：
Gin, Douglas L.
中科院分区：
文献类型：
--
作者：
Carlisle, Trevor K.;Bara, Jason E.;Gin, Douglas L.
在这项工作中，通过实验和理论相结合的方法，探索了利用附加官能团调节室温离子液体（RTILs）的溶解度参数。通过可预测地改变几种RTIL溶剂的溶解度参数，对它们的气体溶解度和分离性能进行了调整。这一概念通过合成和表征含有腈基和炔基官能取代基的咪唑基RTILs得以证明。测量了这些RTILs在接近环境温度和压力下对CO₂、N₂和CH₄的理想溶解度和选择性值。与类似的无官能团、正烷基取代的RTILs相比，这些官能化的RTIL溶剂表现出较低的CO₂、N₂和CH₄溶解度值，但提高了CO₂/N₂和CO₂/CH₄的溶解度选择性。采用基团贡献法预测官能化RTILs的溶解度参数，并将这些值与正规溶液理论一起用于预测三种气体的溶解度和选择性。发现这些预测的气体溶解度值与实验测量值吻合良好。此外，基团贡献法的预测表明，与类似的正烷基取代的RTILs相比，腈基和炔基官能团的引入提高了溶解度参数。这些初步结果表明，基团贡献法为系统设计具有特定气体溶解度和选择性性能的官能化RTILs提供了有价值的指导。
In this work, tuning the solubility parameter of room-temperature ionic liquids (RTILs) with appended functional groups was explored using a combination of experiment and theory. By predictably altering the solubility parameters of several RTIL solvents, their gas solubility and separation perfon-nance were tailored. This concept was demonstrated by synthesizing and characterizing imidazolium-based RTILs that incorporate nitrile and alkyne functional substituents. The ideal solubility and selectivity values of CO2, N-2, and CH4 at near ambient temperature and pressure were measured for these RTILs. These functionalized RTIL solvents exhibited lower CO2, N-2, and CH4 solubility values but improved CO2/N2 and CO2/CH4 solubility selectivity when compared to analogous nonfunctionalized, n-alkyl-substituted RTILs. A group contribution method was used to predict the solubility parameters of the functionalized RTILs, and these values were used with regular solution theory to predict the solubility and selectivity of the three gases. These predicted gas solubility values were found to be in good agreement with those measured experimentally. Furthermore, the predictions from the group contribution method indicated that inclusion of the nitrile and alkyne functional groups increased the solubility parameter relative to the analogous, n-alkyl-substituted RTILs. These initial results show that the group contribution method offers a valuable guide for systematically designing functionalized RTILs with specific gas solubility and selectivity performance.