Theoretical Study on Interaction Between Ionic Liquids and Aromatic Sulfur Compounds

Abstract

It is important to understand how ionic liquids interact with aromatic sulfur compounds in view of ionic liquids application in desulfurization from fuels. Ion pairs of N, N-dialkylimidazolium dialkylphosphate ionic liquids were optimized at the Becke3LYP level of density functional theory. The most stable geometries were obtained. The stable ion pairs indicate there exist hydrogen bonding interactions between them. The calculated interaction energies of ion pairs were found to increase in magnitude with decreasing alkyl chain length, and with decreasing anionic radius. Furthermore, the interactions between the IL and aromatic sulfur compound, and benzene molecule were investigated. The results indicate that there exist hydrogen bonds between them. The calculated interaction energy between IL and sulfur compound is larger than that between IL and benzene. The aromatic ring π - π interaction and hydrogen bonding interaction may be the dominant factors to influence the trend of interaction between ILs and aromatic sulfur compounds.

The selectivity for sulfur removal from oils: An insight from conceptual density functional theory

“…However, the selectivity for metal‐based ionic liquids is very complicated. The extractive mechanisms were mainly ascribed to hydrogen bond and π‐π interactions as well as CH‐π interactions . Similar order can be found in Figure b (electron affinity) and Figure e (electrophilicity).…”

“…In ADS system, the removal mechanism is suggested to be the π‐π interaction between sulfides and sorbents . While in EDS system, the mechanisms were mainly ascribed to hydrogen bond and π‐π interactions as well as CH‐π interactions . Both of the mechanisms are not related to the electron densities of sulfur atoms.…”

Theoretical Study on Interactions between N-Butylpyridinium Nitrate and Thiophenic Compounds

“…17 The interactions between N,N-dialkylimidazolium dialkylphosphate ionic liquids and aromatic sulfur compound, benzene were investigated by density functional theory. 18 The theoretical studies on desulfurization by imidazolium-based ionic liquids were highlighted. But the theoretical study on removal of sulfur by extraction of pyridinium-based ionic liquids was less reported.…”

Ionic liquid [BMIM][Cl] immobilized on cellulose fibers from pineapple leaves for desulphurization of fuels

“…The previous assays studied a mix of aromatic compounds (thiophene and benzothiophene) but the removal percentage was always expressed as total mg S/L. Several researchers stated that the extraction of aromatic compounds with imidazolium-based ionic liquids occurs by H-bonding (between the cation of the IL and the S atom of the sulfur compound) as proposed by Nie et al [44] However, a good number of researchers concluded that the interaction between the IL and the S-compounds are - type between the -electrons of imidazolium cation and the -electrons of the S-compounds [45][46][47][48]. Using the experimental conditions established in the previous assays we determined the final concentration of each aromatic compound after each cycle of extraction by GC-FID and calibration curves for each compound.…”