Liquid liquid equilibria of imidazolium based ionic liquid + pyridine + hydrocarbon at 298.15 K: Experiments and correlations

In this work, 1-ethyl 3-methylimidazolium methylsulfonate [EMIM][MeSO3], 1-ethyl 3-methylimidazolium ethylsulfate [EMIM][EthSO4] and 1-ethyl-3-methylimidazolium acetate [EMIM][Ac] were investigated as green solvents for the denitrification of diesel oil at T = 298.15 K and atmospheric pressure. The liquid liquid equilibrium (LLE) data for the ternary mixture of [EMIM][MeSO3] (1) + pyridine (2) + n-pentane/isooctane (3), [EMIM][EthSO4] (1) + pyridine (2) + 1-pentane/isooctane (3) and [EMIM][Ac] (1) + pyridine (2) + n-pentane/isooctane (3) systems were experimentally determined at ambient conditions. In all the systems, the tie lines had a negative slope at higher concentrations of pyridine, implying higher quantity of ionic liquid is required for the separation of pyridine from hydrocarbon. It was found that at lower concentrations of pyridine in feed, [EMIM][Ac] and [EMIM][MeSO3] are the potential solvents for the extraction of pyridine from n-pentane and isooctane respectively. The experimental results were well correlated with predicted values via NRTL and UNIQUAC models. The average RMSD obtained in NRTL and UNIQUAC models for all the six systems were 1.15% and 1.9% respectively.