One-step propylene purification from a quaternary mixture by a single physisorbent

One-step removal of multiple impurities implemented by adsorptive separation is an efficient and simple process to afford high purity products, but is hindered by the lack of advanced porous materials that could capture different types of molecules. Herein, a series of novel metal-organic frameworks ZU-921 to ZU-924 with cooperative binding environment of integrated aromaticity surface and fluorine/oxygen electronegative sites are designed, and ZU-921 is presented as the demonstration that solves the long-standing challenge in one-step propylene (C₃H₆) purification from the C3 quaternary mixture. The selective recognition ability towards alkyne, allene, alkane than alkene implemented by ZU-921 is attributed to the optimal interaction contribution from polarizability and dipole/quadruple moments that is realized by the fine-tuned density of parallelly-distributed electronegative sites via ligand engineering strategy. Ultra-high purity (99.99%) C₃H₆ could be directly obtained from the C3 quaternary mixture (C₃H₄/C₃H₄(PD)/C₃H₈/C₃H₆ 1 v/1 v/3 v/95 v) with the productivity of 17.27 L/kg derived from the 10-times scale-up column (1.0 cm × 50 cm) breakthrough experiment. This work not only presents a common strategy in advanced adsorbents design for multiple impurities capture but also provides an energy-efficient alternative for C₃H₆ purification.