Effective Separation of Xylene Isomers by a Chain-like Coordination Polymer
Xylene isomers are important raw chemicals used for manufacturing a variety of industrial commodities. However, separation of these isomers by either distillation or adsorption remains a challenging process because they have very similar molecular size, shape and physical properties (e.g., nearly the same boiling points). The distillation method is extremely energy intensive, while the adsorption method using conventional adsorbent (e.g. zeolites) suffers from low selectivity and often requires high temperature. Developing highly efficient adsorbents with excellent adsorption capacity and selectivity is crucial for the implementation of simulated moving bed (SMB) technology for the industrial separation and purification of the xylene isomers. In a very recent work published in Science, the research teams of Prof. Jing Li (Rutgers University, https://chem.rutgers.edu/jinglilab) and Prof. Zongbi Bao (Zhejiang University) reported the use of a stacked one-dimensional (1D) coordination polymer, [Mn(dhbq)(H2O)2] (H2dhbq = 2,5-dihydroxy-1,4-benzoquinone) to effectively separate the three xylene isomers. The unique temperature-adsorbate dependent adsorption behavior of the polymer enables full separation of p-, m- and o-xylene isomers in both vapor and liquid phase. The delicate stimuli-responsive swelling of the structure endows this porous material with exceptionally high flexibility, stability, and well-balanced adsorption capacity, high selectivity and fast kinetics at conditions mimicking industrial settings. This study may offer an alternative approach for energy-efficient, adsorption-based industrial separation and purification of xylene isomers
PUBLICATION: Li, L.Y.; Guo, L.D.; Olson, D.H.; Xian, S.K.; Zhang, Z.G.; Yang, Q.W.; Wu, K.Y.; Yang, Y.W.; Bao, Z.B; Ren, Q.L.; Li, J. “Discrimination of Xylene Isomers in A Stacked Coordination Polymer”, Science, 2022, 377, 335-339, DOI: 10.1126/science.abj7659.