Design And Synthesis Of Functionalized Ionic Liquids And Their Application In Light Oil Denitrification

Along with more attention being paid to environmental protection worldwide,most countries have made laws or regulations to restrict the nitrogen content in fuel oilto a more rigorous standard. Among these techniques, the extraction denitrificationwith ionic liquids (ILs), which has many advantages such as low investment, simpletechniques, mild conditions, easy separation etc, shows promising as an approach forthe deep denitrification of fuel oil.95kinds of ILs have been designed and synthesized whose cations includeN-methylimidazole, triethylamine, pyridine and N, N-dimethylaniline. Their structureswere characterized by1H NMR and FT-IR. Among them,15ILs have not beenreported with N, N-dimethylaniline cations. Comparing with other cations, these newILs have many advantages such as simple operation, easy access to raw materials, lowcost etc.Most of the synthetized ILs are Br nested acidic ILs, with cheap anions such asHSO4-, H2PO4-, BF4-, CH3COO-, CCl3COO-, CF3COO-, CH3SO3-, CH3PhSO3-etc. Theacidity of ILs was tested by pH meter. The results indicated that the acidity of ILs isdetermined by anions, cations produce less effect. Functional group SO3H leading intoside chain can significantly enhance the acidity of ILs. For same cations, the acidity ofILs as the following order: HSO4-> BF4-> H2PO4-; CF3COO-> CCl3COO-> CH3COO-;CH3SO3->p-CH3PhSO3-, which consistent with the acidity of corresponding Br nstedacid.The synthesized ILs were used to extract denitrogenation of modal oil containingbasic nitrogen; here, aniline, pyridine and quinoline are selected as N-compounds; Theeffects of mass ratio of IL/oil, IL/H2O, temperature, time and settlement time ondenitrogenation efficiency were investigated. As for the basic nitrogen components, itwas indicated that the mass ratio of IL/oil and settlement time were main factors, the denitrification experiment can be completed in30min at room temperature, and waterof being added is beneficent to the reaction. The denitrification efficiency is better withthe acidity of ILs is stronger. The possible liquid-liquid extraction reactionmeachanism was proposed, which was catalyzed by acid and promoted by water.For the removal of neutral nitrogen compound (indole) in modal oil with ILs, theresults suggested that the acidic ionic liquids functionalized with SO3H exhibitexcellent denitrification efficiency and selectivity. The acidity of ILs still promoted toincrease denitrification efficiency. Distinct from the condition of basic nitrogenremoval, the reaction temperature of removal indole rose, reaction time and settlingtime extended. Under the condition of the mass ratio of IL/oil increases and withoutwater, it can also produce good denitrification effect. As a result of reasoning andexperiment, the reaction mechanism of removal indole with SO3H functionalILs isliquid-liquid extraction which catalyzed by acid and restrained by water.After a series of denitrification experiments toward simulate oil, such as singlecomponent basic nitrogen, single component neutral nitrogen, multicomponent basicnitrogen and mixed nitrogen, ILs which show high selectivity for basic and neutralnitrogen were selected and the denitrification process routes were optimized. Furtherresearch was carry out for real93#gasoline, the results indicate that N,N-dimethylaniline based ILs: DMAPSHSO4, BSDMAHSO4, BSDMABF4can remove81.83%,84.45%,88.80%of the total nitrogen in gasoline respectively; And triethylamine basedILs: N2224HSO4, N222PSHSO4, N2222HSO4can remove90.95%,95.09%and96.67%ofthe total nitrogen content in gasoline respectively, achieved excellent removal effect.Br nsted acidic ILs selected for denitrification showed highly selectivity to basicand netual nitrogen, they were insensitive to water and air. The denitrogenationefficiency had little significant decline after using6times. The reused ILs wereanalyzed by FT-IR, it was demonstrated that there was no significant change in itschemical structure. All these results indicated that these ILs had excellent chemicalstability and recycling.This study expanded the application of ILs in the field of thepetrochemical engineering, and provided guidance for ILs to be used in this field.