Measurement of phase equilibria data for the extraction of toluene from alkane using different solvents

Abstract

In the petrochemical industry, the separation of aromatics from alkanes is a complex process due to the overlapping boiling points and azeotrope formation in specific operational conditions. In this work, 2-hydroxy ethylammonium formate (2-HEAF) and glycerol were evaluated as an extractor solvent of toluene from decane+toluene mixtures, by comparing with widespread solvent used in industrial applications, sulfolane. New liquid–liquid equilibrium (LLE) data for three ternary systems: {decane (1)+toluene (2)+glycerol (3); decane (1)+toluene (2)+[2-HEAF] (4); and decane (1)+toluene (2)+sulfolane (5)} at T=(303.15 and 333.15)K and atmospheric pressure has been studied. Heterogeneous region in LLE diagram presents a wide area and are not influenced by temperature, in the studied domain. From experimental data, distribution coefficients and selectivity parameters have been used determined and used to evaluate the efficiency of the studied solvents (sulfolane, glycerol and 2-HEAF) to extract toluene from decane. Two thermodynamics models (NRTL and UNIQUAC) were used to obtain binary interaction parameters. These models have been also used to correlate LLE experimental data for the studied ternary systems. A comparison between experimental and calculated data indicate that better agreement has been performed by using NRTL model.