Highly Efficient Nitric Oxide Capture by Azole-Based Ionic Liquids through Multiple-Site Absorption

A novel method for highly efficient nitric oxide absorption by azole-based ionic liquid was reported. The NO absorption capacity reached up to 4.52 mol per mol ionic liquid and is significant higher than the capacity other traditional absorbents. Moreover, the absorption of NO by this ionic liquid was reversible. Through a combination of experimental absorption, quantum chemical calculation, NMR and FT-IR spectroscopic investigation, the results indicated that such high capacity originated from multiple-site interactions between NO and the anion through the formation of NONOate with the chemical formula R¹ R² N-(NO^- )-N=O, where R¹ and R² are alkyl groups. We believe that this highly efficient and reversible NO absorption by an azole-based ionic liquid paves a new way for gas capture and utilization.