Extraction separation of aromatic homologues from n-decane using DMSO: Influence of the alky side chain length

Abstract In this study, the liquid-liquid equilibrium of DMSO-aromatic homologues-n-decane systems were measured at 303.15 K under 101.3 kPa at first, followed by Other-Tobias equation data reliability verification and NRTL/UNIQUAC activity coefficient model correlation. Moreover, intermolecular interaction energies and molecular polarity indexes were calculated to interpret the extraction results. Finally, a set of wave function analyses were accomplished to elaborate the physical nature of the interaction concerning alky side chain length in DMSO extraction process. These investigations show that: (1) Both aromatics extraction and alkane entrainment are in the order of toluene > ethylbenzene > isopropylbenzene (cumene). (2) Intermolecular interaction energy and molecular polarity index can characterize the interaction intensity between the stationary dimer. (3) The interactions between aromatics and DMSO are weak hydrogen bonding and van der Waals interaction. The attractive part mainly involves dispersion (50.54 ∼ 53.30%) and electrostatic (35.49 ∼ 37.67%) effect. (4) The interaction between aromatics and n-decane are van der Waals interaction, dominated by attractive dispersion (70.41 ∼ 70.86%) and repulsive exchange effect. With the extension of the alky side chain, the electrostatic contribution decreases, while the dispersion contribution increases.