Liquid-Liquid equilibria of ternary mixtures of alkane (C8 or C12) + thiophene + three methylimidazolium dicyanamide (DCA)-based ionic liquids

Abstract

It is becoming eminent in the oil refining industry to diminish the sulfur content in their fuels to limit the harmful emissions of sulfur oxides (SOx) to public health and the environment. Liquid–liquid extractions of thiophene from paraffin compounds have been investigated using 1-ethyl-3-methylimidazolium dicyanamide [emim][DCA], 1‑butyl‑3-methylimidazolium dicyanamide [bmim][DCA], and 1-benzyl-3-methylimidazolium dicyanamide [bzmim][DCA] ionic liquids at 313.15 K and an atmospheric pressure of 101.3 kPa. Liquid–liquid equilibrium data for the three ternary systems: {iso-octane (1) + thiophene (2) + [emim][DCA] or [bmim][DCA] (3)} and {tetradecane (1) + thiophene (2) + [bzmim][DCA] (3)} were determined. In addition, distribution ratios and selectivity values were computed and compared for these systems to evaluate the desulfurization competence (aptitude). The thermodynamic nonrandom two-liquid (NRTL) model was used to correlate the experimental data.

Keywords

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