Theoretical Study On Ionic Liquid Desulfurization And Denitrification

In order to understand the interactions between ionic liquids and sulfur-containing and nitrogen-containing compounds,and to provide guidance for the design of ionic liquids,a density functional theory(DFT)study was carried out to investigate the interactions between ionic liquids and sulfur-containing and nitrogen-containing compounds.The ionic liquids were optimized by the Gaussian 09 software at the coB97X-D or B3LYP/6-31++G(d,p)level.The results show that the positive potential of the cation is mainly located on the aromatic ring,and the negative potential of the anion is mainly on the polar atomsThe study on the interaction of the imidazolyl ionic liquid with thiophene(TP)indicates that the anions are easier to form interactions with the imidazole ring compared to thiophene Hydrogen bonds play an important role in the adsorption of thiophene,and π-π stacking effects between[BMIM][ZnCl3]ionic liquid and TP are also important.As for the molecular sieve supported ionic liquid,the steric factor of the molecular sieve influences the π-π stacking effect of the anion on the imidazole ring.The interaction energy of[BMIM][BF4],[BMIM][ZnCl3]and SBA-[BMIM][ZnCl3]were 36.87 kJ/mol,37.20 kJ/mol and 36.43 kJ/mol,respectivelyThe interaction between[BF4]-based ionic liquid and dibenzothiophene(DBT)shows that the interaction energy between[BF4]--based ionic liquid and DBT was higher for the ionic liquids with aromatic ring than that with alicyclic ring.The π-π interaction is the dominant interaction between the cation and the DBT position.The π+ cation tends to stack on the intermediate DBT ring,and the hydrogen bond plays an important role in controlling the cation-anion structure.From the NBO and AIM results,the intensity of the weak interaction in ionic liquids-DBT follows the order of:F H>π+-π>N-C-H…C>anion-π.The interactions of the ionic liquid which contains an ester group in the cation,which is a biodegradation promotor,with different nitrogenous compounds suggests that:usually the lowest potential in the anion side interaction with the most positive edge in the aromatic nitrogen compounds,and this interaction has a low space resistance.Cation locates at the top of the ring of nitrogen compound,forming the parallel structure of the D-type π+-π stacking effect,or the positive potential on the edge of the H in the cation perpendicular to the nitrogen compounds,forming T-π+ Stacking effect.In addition,the interactions between ionic liquids and the different types of sulfur-containing and nitrogen-containing aromatic compounds follow the order:nitrogen-containing aromatic compounds>sulfur-containing aromatic compounds>aromatic compounds without heteroatoms.