Effect of 2-Pyrrolidone Protic Ionic Liquids on Removal of Pyridine from Fossil Fuel Model Mixtures

To reduce emission of nitrogen oxides (NO x ) mainly produced from the combustion of nitrogen compounds (NCs) in fossil fuels, it is necessary to decrease the NCs content in fossil fuels. 2-Pyrrolidone-based protic ionic liquids (PrILs) with three different anions were synthesized by a one-step method. The three PrILs were used as extractants to extract pyridine from the model mixtures. The extraction efficiency ( EE ) was considered to evaluate the extraction performance of the PrILs. The interactions between the PrILs and pyridine were analyzed by σ-profiles, bond length, and deformation charge density. The results show that the hydrogen bond (H-bond) formed between pyridine and the three PrILs is the main driving force for the extraction of pyridine from the model mixtures.