Rapid extraction of trace benzene by a crown-ether-based metal-organic framework

Zhonghang Chen; Peiyu Fang; Jiangnan Li; Xue Han; Wenhao Huang; Wenyue Cui; Zhiwei Liu; Mark R Warren; David Allan; Peng Cheng; Sihai Yang; Wei Shi

doi:10.1093/nsr/nwae342

Rapid extraction of trace benzene by a crown-ether-based metal-organic framework

Natl Sci Rev. 2024 Oct 3;11(12):nwae342. doi: 10.1093/nsr/nwae342. eCollection 2024 Dec.

Authors

Zhonghang Chen¹, Peiyu Fang², Jiangnan Li², Xue Han³, Wenhao Huang¹, Wenyue Cui¹, Zhiwei Liu², Mark R Warren⁴, David Allan⁴, Peng Cheng^{1

5}, Sihai Yang², Wei Shi¹

Affiliations

¹ Frontiers Science Center for New Organic Matter, Key Laboratory of Advanced Energy Materials Chemistry (MOE), and State Key Laboratory of Advanced Chemical Power Sources, College of Chemistry, Nankai University, Tianjin 300071, China.
² Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
³ College of Chemistry, Beijing Normal University, Beijing 100875, China.
⁴ Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE, UK.
⁵ Haihe Laboratory of Sustainable Chemical Transformations, Tianjin 300192, China.

Abstract

Due to almost identical boiling points of benzene and cyclohexane, the extraction of trace benzene from cyclohexane is currently performed via the energy-intensive extractive distillation method. Their adsorptive separation by porous materials is hampered by their similar dimensions. Metal-organic frameworks (MOFs) with versatile pore environments are capable of molecular discrimination, but the separation of trace substrates in liquid-phase remains extremely challenging. Herein, we report a robust MOF (NKU-300) with triangular channels decorated with crown ether that can discriminate trace benzene from cyclohexane, exhibiting an unprecedented selectivity of 8615(10) for the mixture of benzene/cyclohexane (v/v = 1/1000). Remarkably, NKU-300 demonstrates exceptional selectivities for the extraction of benzene from cyclohexane over a wide range of concentrations of 0.1%-50% with ultrafast sorption kinetics and excellent stability. Single-crystal X-ray diffraction and computational modelling reveal that multiple supramolecular interactions cooperatively immobilise benzene molecules in the triangular channel, enabling superior separation performance. This study will promote the application of advanced sorbents with tailored binding sites for challenging industrial separations.

Keywords: benzene/cyclohexane separation; crown ether; crystal structure; metal-organic frameworks; triangular channel.