Extraction of N- and S-compounds in gasoline and diesel from ionic liquids: A molecular dynamics study

• Published in: Journal of molecular liquids 2024-03, Vol.397, p.124102, Article 124102
• Main Authors: Núñez-Rojas, Edgar, Alarcón, Karen González, Alejandre, José
• Format: Article
• Language: English
• Subjects: Diesel; Extraction; Force field; Gasoline; Molecular dynamics
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2024.124102

The extraction of nitrogen and sulfur compounds from gasoline and diesel, using ionic liquids, is conducted through liquid-liquid molecular dynamics simulations. The novel united atom parameters of pyridine, benzene and thiophene which possess a constant dipole moment successfully reproduce the experimental dielectric constant and solubility in water. These molecular parameters are transferred to simulate toluene and dibenzothiophene. Regarding polar liquids, the coexisting densities and surface tension as functions of temperature align excellently with experimental data. The liquid density and surface tension of modeled diesel and gasoline also match experimental data well although the viscosity is underestimated. Ionic liquids comprise positive ions of imidazolium, pyrrolidinium, pyridinium and trimethyl ammonium varying in hydrocarbon chain length. The anion is bis(trifluoromethylsulfonyl)imide. It has been discovered that the new parameters significantly enhance the extraction of nitrogen and sulfur compounds from hydrocarbon mixtures compared to simulation results from TraPPE-UA force field where the molecules possess zero molecular dipole moment. The extraction efficiency of ionic liquids aligns excellently with experimental results at room temperature. •Extraction of N- and S-compounds is an important issue in industry, since they are related with health and economics.•Molecular dynamics is an important methodology to study extraction and the force field is the most important matter.•Many force fields available are not capable to reproduce miscibility and therefore they have to be re-parameterized.•Polarization of ring-like molecules in the force field is an essential issue to reproduce extraction of N- and S-compounds.