Removal of Basic Nitrogen Compounds from Diesel Fraction with NMP-0.5ZnCl2 Coordinated Ionic Liquid

An inexpensive coordinated ionic liquid NMP-0.5ZnCl2 was synthesized by reacting N-methyl-pyrrolidone with anhydrous ZnCl2, and its structure was characterized with FT-IR spectroscopy. The performance of IL for removing basic nitrogen compounds from model oil containing quinoline and actual coker diesel was studied. Experimental results showed that the IL, NMP-0.5ZnCl2, exhibited a good denitrogenation performance, which can be attributed to its low viscosity and unoccupied orbitals of Zn ion, while obtaining a 99.68％ quinoline removal efficiency under conditions covering a temperature of 50 ℃, an IL/model oil mass ratio of 1:2, and a reaction time of 30 min. In the case of coker diesel, above a 91％ basic N-removal efficiency (with N-content reduced from 536 μg/g to 47 μg/g) was realized by the IL after 5-stage extraction. Moreover, the quinoline extraction efficiency could still reach 96.73％ during four recycles of the IL.