Simultaneous interaction between similar and dissimilar structures of aromatic sulfur and aromatic nitrogen compounds with imidazolium-based ionic liquid using quantum chemical method

Molecular structure, interaction energy, orbital energy, partial charges, and molecular properties of the complex system of 1-ethyl-3-methylimidazolium ethylsulfate ([EMIM][EtSo4]) + similar or dissimilar structure of thiophene/benzothiophene/dibenzothiophene/pyrrole/indole/indoline/carbazole/benzacarbazole/pyridine/quinoline/benzoquinoline were predicted using quantum chemical method with 6-31G* basis set. Subsequently, the sigma profile was generated for the similar molecules in the system in order to explain the cause of solvent selectivity and capacity for simultaneous desulfurization and denitrification of liquid fuels. Furthermore, the activity coefficients at infinite dilution of similar or dissimilar structure of compounds in [EMIM][EtSo4] were predicted using quantum chemical method to understand the chemical behavior of [EMIM][EtSo4] with similar or dissimilar structure of the molecules in the complex system. On the other hand, the solvent selection parameters such as selectivity, capacity, and performance index were calculated from the predicted activity coefficient at infinite dilution for all the studied species. The solvent selection parameters showed high values for low order of aromatic ring compounds (i.e. pyrrole, indole, indoline, carbazole, pyridine, quinoline, and thiophene) but gave low values for high order of aromatic compounds like benzothiophene, dibenzothiophene, benzacarbazole, and benzoquinoline. © 2015 Curtin University of Technology and John Wiley & Sons, Ltd.