Torkzadeh Mehrangiz, Moosavi Majid
Department of Physical Chemistry, Faculty of Chemistry, University of Isfahan Isfahan 81746-73441 Iran
RSC Adv. 2022 Dec 9;12(54):35418-35435. doi: 10.1039/d2ra05805g. eCollection 2022 Dec 6.
A few studies on CO capture using dicationic ionic liquids (DILs) show that they are more promising absorbents for CO capture than monocationic ILs (MILs). Ion-ion, ion-CO and DIL molecule-CO interactions are important for understanding the performance-structure-property relationships for the rational design of DILs for CO capture applications. However, the role of these interactions in determining CO solubility in DILs is unclear. In this study, we used DFT methods to understand these interactions in three selected DILs)considering the effects of alkyl side chain length and symmetry in cations (by exploring different aspects, such as the electronic and geometrical structures, topological properties and the strength and nature of interactions, charge transfer, The results showed that the most suitable solvent for CO is the symmetric DIL with a longer side chain length, [Bis(mim)C-(C)][NTf]. In addition, we used the COSMO-RS calculations to obtain the macroscopic solubility of CO in the studied DILs, which was in good agreement with the DFT results. Gas selectivity results calculated using COSMO-RS theory indicated that the selectivity of CO from H, CO and CH gases decreases slightly with increasing the length of side alkyl chains.
一些关于使用双阳离子离子液体（DILs）捕集CO的研究表明，与单阳离子离子液体（MILs）相比，它们是更有前景的CO捕集吸收剂。离子-离子、离子-CO和DIL分子-CO相互作用对于理解用于CO捕集应用的DILs合理设计的性能-结构-性质关系很重要。然而，这些相互作用在决定CO在DILs中的溶解度方面所起的作用尚不清楚。在本研究中，我们使用密度泛函理论（DFT）方法来理解三种选定DILs中的这些相互作用，考虑阳离子中烷基侧链长度和对称性的影响（通过探索不同方面，如电子和几何结构、拓扑性质以及相互作用的强度和性质、电荷转移）。结果表明，对于CO最合适的溶剂是具有较长侧链长度的对称DIL，即[双（mim）C-（C）][NTf]。此外，我们使用COSMO-RS计算来获得CO在所研究DILs中的宏观溶解度，这与DFT结果吻合良好。使用COSMO-RS理论计算的气体选择性结果表明，从H₂、CO和CH₄气体中选择CO的选择性随着侧链烷基长度的增加而略有降低。
