This study investigates the liquid-liquid equilibria (LLE) of a ternary system comprising cyclohexene,

cyclohexane, and a betaine-glycerol deep eutectic solvent (DES) at 303.2 K, 313.2 K, and 323.2 K. The DES was

synthesized using a 1:5 molar ratio of betaine to glycerol. LLE data were correlated using Non-Random Two-Liquid

(NRTL) and Universal Quasi-Chemical (UNIQUAC) models. Distribution coefficients (D1) for cyclohexene decreased

with increasing temperature, ranging from 0.06 at 303.2 K to 0.02 at 323.2 K for a cyclohexene mole fraction of 0.8 in

the raffinate phase. Selectivity (S) values exceeded 1 at higher cyclohexene concentrations. The Othmer-Tobias equation

confirmed data consistency with r2 values close to 1. UNIQUAC model showed superior performance with lower RMSD

values compared to NRTL. This research demonstrates the potential of betaine-based DES as an environmentally friendly

alternative for cyclohexene/cyclohexane separation in petrochemical processes.

deep eutectic solvent, distribution coefficient, liquid-liquid equilibrium, selectivity, correlation

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Authors
YoonKook Park: Professor, Department of Biological and Chemical
Engineering, Hongik University, Sejong, 30016, Korea; parky@hongik.ac.kr