Extractive separation of tetralin-dodecane mixture using tetrabutylphosphonium bromide-based deep eutectic solvent

Separation of components of light cycle oil (LCO) into aromatic-rich and nonaromatic-rich fractions is the essential step for upgrading LCO to produce benzene, toluene, xylene enriched fraction, and high-quality diesel. In this work, extractive separation of model LCO which contains 70 wt% tetralin and 30 wt% dodecane was performed using deep eutectic solvent (DES) as the extractant and water as the anti-extractant. Tetrabutylphosphonium bromide (TBPB) and levulic acid (LA) at a molar ratio of 1:4 was determined as the extractant, due to its high and stable performance during extraction and regeneration processes. The liquid-liquid equilibrium data of ternary systems involving TBPB:LA(1:4) were then experimentally determined and fitted using non-random two-liquid model. The continuous extraction process was simulated and optimized, high mass purity (0.980 for tetralin and 0.987 for dodecane) and high recovery ratio (0.994 for tetralin and 0.954 for dodecane) were achieved.