Liquid–Liquid-Phase Equilibrium for Quaternary Systems (n‑Decane + 1‑Tetradecene + 1‑Methylnaphthalene + Sulfolane/Dimethyl Sulfoxide) for Separation of 1‑Methylnaphthalene from FCC Diesel

Clean utilization of catalytically cracked diesel is of paramount importance in the industry. The separation of polycyclic aromatic hydrocarbons (PAHs) from catalytically cracked diesel can significantly reduce the content of aromatics and increase the cetane number to improve the quality of diesel. In this work, for extracting the PAH 1-methylnaphthalene from the model fluid catalytic cracking diesel, the liquid–liquid equilibrium phase behavior for the quaternary systems (n-decane + 1-tetradecene + 1-methylnaphthalene + sulfolane/dimethyl sulfoxide) were explored at 303.15, 323.15, and 343.15 K under 0.1 MPa. The separation performance was characterized by the separation factor and distribution coefficient. The results showed that sulfolane was a suitable extractant compared to DMSO. The reliability of the measured phase equilibrium data was evaluated by the Hand and Othmer–Tobias equations. The UNIQUAC and NRTL models were applied to fit the tie-line data of the investigated mixtures with the AARD and rmsd lower than 0.01. The intermolecular interaction was explored by the σ-profile analysis to compare the separation performance of sulfolane and DMSO.