Molecular dynamics simulation for desulphurization of hydrocarbon fuel using ionic liquids

Ionic liquids, forming a newer class of green solvents, have shown potential in solvent extraction due to their remarkable physical and chemical properties, which can be tailored for specific tasks. Ionic liquids are one of the potential extractants for desulphurization of crude oil to produce ultra-low sulphur fuels. However, due to the constraints of economic feasibility and the broad domain of Ionic liquids, their varying affinity towards sulphur impurities along with the overall expensive methods of production, limit the selection of an Ionic Liquid that provides optimum extraction rates. We investigated the biphasic extraction of two sulphur compounds, thiophene and dibenzothiophene (DBT) from dodecane by using ionic liquid systems of ethyl methyl imidazolium (EMI) and butyl methyl imidazolium (BMI) cations; and tetrafluoroborate (BF4) and thiocyanate (SCN) anions. The molecular arrangement and extraction mechanism of both sulphur compounds at the interface of dodecane-ionic liquid system are studied by molecular dynamics (MD) simulations. We observed that electrostatic interactions between the aromatic plane of sulphur compounds and cations of ionic liquids are the major forces responsible for the extraction of sulphur compounds. (C) 2018 Elsevier B.V. All rights reserved.