Olefin separation from FCC naphtha by deep eutectic solvents: PC‐SAFT modeling and molecular insights

Olefin extractive separation from fluid catalytic cracking (FCC) naphtha with deep eutectic solvents (DESs) was systematically investigated in this work. In a first step, different DESs were screened for their separation performance of the binary mixture benzene/1‐hexene. The DES TEBAC:EG composed of triethyl benzyl ammonium chloride (TEBAC) and ethylene glycol (EG) was selected as the most promising extractant. In a second step, Perturbed‐Chain Statistical Associating Fluid Theory (PC‐SAFT) was used to quantitatively predict liquid–liquid equilibria (LLE) of DES‐related systems, so‐called “complex organic hydrogen bonding network systems”. For the first time, PC‐SAFT was used based on the pure components of the DESs, which allows predicting also the effect of the HBA:HBD ratio of the DES on the LLE. In a third step, the separation mechanism at the molecular level was unraveled by quantum chemical (QC) calculations, indicating that TEBAC:EG has much stronger intermolecular interactions with the organic solvents than sulfolane has.