Ionic liquids can capture CO2; however, it is not clear how this gas dissolves in this medium. Examining ionic liquids is a challenge as they are entirely made of ions with nanoscale segregation. Though there are many hypotheses, a clear experimental answer is yet to emerge. In particular, there are very few experimental designs to study the cation-CO2 interaction. To this end, we have developed protocols to modify the C-2 position of imidazolium cation with a C-D infrared marker. Our results show that the C-D infrared lineshape of modified imidazolium-based ionic liquids is sensitive to the anion. More importantly, the antisymmetric vibration of dissolved CO2 can be observed in thes C-D modified ionic liquids. Thus, the two spectroscopic handles, CO2 and C-D, can be used to study CO2-cation interactions. This work demonstrates the potential to tease out the CO2-cation interactions using vibrational spectroscopy.

Using C-D vibration to study CO2-ionic liquid interactions

255th National Meeting (2018)

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