Ternary Liquid-Liquid Equilibrium Data for the N-Formylmorpholine + Toluene + { n-Nonane or n-Decane} Systems at (303.2, 323.2, and 343.2) K and 101.3 kPa

The design and operation of the process to extract aromatics from petroleum intermediates via solvent extraction can be enhanced in terms of efficiency by access to liquid-liquid equilibrium (LLE) data. This study serves to contribute LLE data for a heavy alkane, aromatic, and solvent mixture, which is of limited availability in the open literature. Ternary LLE phase compositions were experimentally measured and thermodynamically modeled for the systems N-formylmorpholine (NFM) + toluene + (n-nonane or n-decane) at 303.2, 323.2, and 343.2 K and 101.3 kPa. The direct analytical method was used to obtain the LLE data using a double-walled glass cell. The phase equilibrium samples were quantitatively analyzed using gas chromatography. The ternary systems were successfully correlated using the non-random two-liquid and universal quasichemical thermodynamic models. The effectiveness of using NFM as an alternative solvent to extract toluene from a mixture containing n-nonane or n-decane was evaluated by determining the selectivity. The plait point for the systems measured was determined using the graphical Coolidge method. All systems studied were found to exhibit type I ternary LLE behavior, and relative selectivity was greater than unity, indicating that the extraction of toluene from heavy alkanes is feasible using NFM.