Optimizing supramolecular interactions within metal–organic frameworks for ultra‐high purity propylene purification

Abstract

Purifying ultra‐high purity propylene (>99.995%) with an energy‐efficient adsorptive separation method is a promising yet challenging technology that remains unfulfilled. Instead of solely considering the effect of adsorbents on guest molecules, we propose a synergistic adsorption mechanism for the deep removal of propane and propyne, utilizing supramolecular interactions in both “host‐guest” and “guest‐guest” systems. Through modulation of the pore environment, Ni‐DMOF‐DM exhibits exceptionally high adsorption capacities for propane and propyne (171 and 197 cm3/g at ambient temperature and pressure, respectively), and unprecedented propane/propylene separation selectivity (2.74). Theoretical calculations confirm the geometric interactions of C‐H···π bonds and C‐H···O hydrogen bonds resulting from host‐guest interactions, alongside C‐H···H guest‐guest interactions within the confined pore space. Breakthrough experiments demonstrated that ultra‐high purity propylene (propane < 0.005% and propyne < 1.0 ppm) can be directly collected from ternary mixtures on Ni‐DMOF‐DM, achieving a productivity of up to 152.14 L/kg.