Recently, researchers from the School of Chemistry and Chemical Engineering of Jiangsu University (JSU) have published their lastest result titled Deep extractive denitrogenation with Cu-based ionic liquids and mechanistic insights in AIChE Journal, a top chemical engineering publication. JSU serves as the primary affiliation for this research achievement. Prof. Zhu Wenshuai and Assoc. Prof. Wu Peiwen jointly serve as the corresponding authors of this paper.
Organic nitrogen compounds (ONCs) present in fuel oils exert various detrimental impacts on both the environment and petroleum processing. Since the 1960s, solvent extraction technology has been recognized as a critical separation technique, with solvent selection constituting its core determinant. This selection criterion primarily depends on the physicochemical properties of the target ONCs, particularly the types of intermolecular interactions involved. Metal-based ionic liquids, leveraging their distinctive Lewis acid-base interactions, have demonstrated unique advantages in the extractive removal of ONCs. However, a persistent bottleneck remains in the precise identification of active species during the extraction process.
This study successfully prepared a series of Cu-based ionic liquids ([Bmim]Cl/CuCl2-X) by varying the anion/cation ratio to modulate the anionic configuration and optimize their performance. Experimental results demonstrated that the sample with a 1:1 anion/cation ratio ([Bmim]Cl/CuCl2-1) exhibited exceptional EDN performance. Combined Raman spectroscopy and theoretical calculations revealed that the unoccupied orbitals of Cu2+ in [CuCl3]- formed effective coordination with nitrogen atoms in ONCs, establishing crucial Lewis acid-base interactions that govern the deep EDN process. The work not only proposes a sort of efficient Cu-based ionic liquid for deep removal of ONCs from fuel oils, but also provides fundamental insights into understanding and regulating the essential interactions during EDN processes.
