Applications Of Superbase-derived Ionic Liquid In Deep Oxidative Desulfurization Of Diesel Fuel

Sulfur oxides produced by combustion of sulfur-contained fuels are the main cause of acid rain,haze and other environment issues.Thus,deep desulfurization of fuels to produce low sulfur-contained fuels,and then reducing emissions of sulfur oxides is one of the important tasks to control environmental pollution.Oxidative desulfurization?ODS?is one of non-hydrodesulfurization technologies with advantages of low energy consumption,flexible operation under the mild condition and the high selectivity.The extraction combined with oxidative desulfurization?ECODS?of functionalized Ionic liquids?ILs?is the important branch of ODS,which can achieve the conversion and desorption of sulfide in fuels at the same time to reach ultra deep desulfuization.Two kinds of superbase-derived Lewis acidic ionic liquids were synthesized in this work,moreover,the dselfurization performance and processes of two kinds of catalysts with H₂O₂ as oxidant in ECODS were systematically investigated.In this paper,a kind of protic superbase-derived ionic liquids[HDBN]Cl/nZnCl₂?n=1,2 and 3?were designed then synthesized,and characterized by ¹H NMR,FT-IR,MS to confirm the chemical structure,which evidenced the conformational transition of[HDBN]⁺cation and the effect to desulfurization performance.A series of systematic experiments were conducted to investigate the influences of different reaction conditions.The result showed that,when the temperature was at 60?,mass ratio of ILs and oil was 1/10,mole ratios of H₂O₂/S was 6/1,the sulfur removal of DBT could reach 100%.The reactivities of different S-compounds were also studied,which suggested that both the electron density of S atoms and the steric hindrance determine the reactive activity.As for the ECODS of real diesel,the S-content could be reduced from 559.7 ppm to 6.5 ppm with 98.8%sulfur removal via one-step process,which indicated the excellent desulfuization performance of the ILs.Based on the principle of transfer catalysis,a kind of amphipathic alkylated superbase-derived ionic liquids[ODBU]Cl/nZnCl₂?n=1,2,3,4 and 5?were synthesized.Enhancing the lipophilic property of ionic liquids to improve interphase mass transfer,and thus the extraction and conversion efficiency of sulfides are also enhanced.The effect on both extractive capability and catalytic activity by the structure and composition of ionic liquids was investigated by systematical ECODS experiments.When the temperature was at 50?,mass ratio of ILs and oil was 1/10,mole ratios of H₂O₂/S was 6/1,DBT could be completely removed in 60 min.The ECODS performance of[ODBU]Cl/3ZnCl₂ was also evaluated using a hydrogenated diesel.The results showed that sulfur removal could approach 99.2%,and complete conversion and extraction of sulfides could be achieved to reach deep sulfur removal.In summary,the superbase-derived ILs in this work have a wide industrial foreground due to the advantages of green,high efficiency,stability and low cost.Furthermore,this study also provides a new research idea and the engineering application value in deep desulfurization by ILs.