Molecular dynamics simulation of the process of extraction desulfurization of model fuel using n-methylpyrrolidone and ionic liquid

Modern environmental requirements stimulate the development of alternative methods for deep purification of hydrocarbon raw materials from sulfurcontaining compounds.One of the promising areas is extraction desulfurization, in particular using ionic liquids as selective extractants.This paper presents a comparative molecular dynamics simulation of the processes of extracting thiophene, a model organosulfur pollutant, from an aliphatic medium (n-hexane) using the organic solvent N-methylpyrrolidone and the ionic liquid N-methylpyrrolidonium acetate obtained on its basis.The simulation was performed using the OPLS-AA potential and the NpT ensemble in a wide temperature range.The behavior of model systems including hexane, thiophene, and the corresponding extractant was analyzed in dynamics from initial mixing to equilibrium.The results showed that in the system with N-methylpyrrolidone, partial phase mixing and less pronounced selectivity are observed, whereas the use of N-methylpyrrolidonium acetate leads to distinct phase separation: up to 80% of thiophene molecules are localized in the ionic phase.The high efficiency of the ionic liquid is explained by its ability to electrostatically interact with polar sulfurcontaining compounds.This allows us to consider N-methylpyrrolidonium acetate as a promising extractant for soft, energy-efficient and selective desulfurization.The obtained data confirm the importance of molecular modeling in the development and optimization of extraction systems for cleaning fuel fractions and create a basis for future applied research