Desulfurization of ternary mixtures of n-paraffins (C12 or C16) + thiophene + two methylimidazolium dicyanamide (DCA)-based ionic liquids

Abstract

Reducing sulfur levels in fuels has gained significant importance in the oil refining sector to curb harmful emissions of sulfur oxides (SOx), impacting public health and the environment. We conducted liquid-liquid extractions of thiophene from n-paraffin compounds, employing 1-ethyl-3-methylimidazolium dicyanamide [emim][DCA] and 1‑butyl‑3-methylimidazolium dicyanamide [bmim][DCA] ionic liquids at 313.15 K and atmospheric pressure (101.3 kPa). The study involved determining liquid-liquid equilibrium data for three ternary systems: {n-dodecane (1) + thiophene (2) + [bmim][DCA] (3)} and {n-hexadecane (1) + thiophene (2) + [emim][DCA] or [bmim][DCA] (3)}. Furthermore, we computed and compared distribution ratios and selectivity values across these systems to assess their desulfurization competency. The thermodynamic nonrandom two-liquid (NRTL) model was employed to correlate the experimental data. UNISIM steady-state simulator was used to estimate the extraction efficiency of thiophene from n-C16 as a model diesel fuel.

Keywords

• Desulfurization
• Fluid phase equilibria
• Extraction
• Ionic liquid
• Thiophene