School of Chemical Engineering, University of Science and Technology Liaoning, Anshan, Liaoning, 114051, China.
School of Chemical Engineering, University of Science and Technology Liaoning, Anshan, Liaoning, 114051, China.
J Chromatogr A. 2022 Jun 21;1673:463091. doi: 10.1016/j.chroma.2022.463091. Epub 2022 Apr 29.
The separation of p-xylene (PX) and m-xylene (MX) isomers with near boiling points is a worldwide problem. The metal-organic framework material is an ideal stationary phase for chromatographic separation because of its high porosity, homogeneous pore diameter and good chemical stability. In this paper, a simulated moving bed (SMB) chromatography system with MIL-53(Fe) as the stationary phase and petroleum ether-dichloromethane as the mobile phase was designed to separate PX and MX at ambient temperature. Firstly, according to the elution curves of a single column, nonlinear competitive Langmuir adsorption isotherm equation was confirmed by equilibrium dispersive chromatography model. Then, the SMB separation zone was determined based on triangle theory, and the SMB operating conditions were optimized. Finally, the purity, recovery and productivity of PX reached 100.0%, 99.1% and 93.1 g/L/h, respectively; the purity, recovery and productivity of MX reached 96.4%, 100.0% and 23.5 g/L/h, respectively; the solvent consumption was 0.42 L/g.
分离具有相近沸点的对二甲苯（PX）和间二甲苯（MX）异构体是一个世界性的难题。金属-有机骨架材料因其具有高孔隙率、孔径均一和良好的化学稳定性，是色谱分离的理想固定相。本文设计了一种采用 MIL-53(Fe) 作为固定相、石油醚-二氯甲烷作为流动相的模拟移动床（SMB）色谱系统，在常温下分离 PX 和 MX。首先，根据单柱的洗脱曲线，通过平衡弥散色谱模型确定了非线性竞争 Langmuir 吸附等温方程。然后，基于三角理论确定了 SMB 分离区，并对 SMB 操作条件进行了优化。最后，PX 的纯度、收率和生产能力分别达到 100.0%、99.1%和 93.1 g/L/h；MX 的纯度、收率和生产能力分别达到 96.4%、100.0%和 23.5 g/L/h；溶剂消耗为 0.42 L/g。
