Liquid−Liquid Equilibria for {1-Ethyl-3-methylimidazolium Diethylphosphate or 1-Ethyl-3-methylimidazolium Ethylsulfate} + 4,6-Dimethyldibenzothiophene + Dodecane Systems at 298.2 K and 313.2 K

Abstract

Liquid−liquid equilibrium (LLE) data for {1-ethyl-3-methylimidazolium diethylphosphate ([emim][DEtPO4]) or 1-ethyl-3-methylimidazolium ethylsulfate ([emim][EtSO4])} + 4,6-dimethyl-dibenzothiophene (4,6-DMDBT) + dodecane systems, at (298.2 and 313.2) K and atmospheric pressure (≈ 95 kPa), were determined by refractometry. 4,6-DMDBT is one of the most difficult diesel sulfur pollutants to remove by the conventional process of hydrodesulfurization (HDS). Extraction of 4,6-DMDBT from dodecane (used as model diesel oil) was analyzed in terms of solute distribution coefficient, solvent selectivity, and percent of extraction. The results indicate that [emim][DEtPO4] is a better solvent for extractive desulfurization of dodecane than [emim][EtSO4]. The Hand and Othmer−Tobias correlations, used to ascertain the quality of the experimental data, presented R2 > 0.98 for systems with [emim][DEtPO4] and R2 > 0.96 for systems with [emim][EtSO4]. The nonrandom two-liquid (NRTL) model was used to correlate the LLE data a...