Propane-Trapping Ultramicroporous Metal–Organic Framework in the Low-Pressure Area toward the Purification of Propylene

Abstract

The propane (C₃H₈)-trapping adsorption behavior is considered as a potential performance to directly produce high-purity propylene (C₃H₆). Herein, we report an ultramicroporous Mn-based metal-organic framework (<b>NUM-7</b>) with a reverse C₃H₈-selective behavior in the low-pressure area. The pore structure of this material possesses more electronegative aromatic benzene rings for the stronger binding affinity to C₃H₈, and the material shows outstanding reverse ideal adsorbed solution theory (IAST) selectivity values. Single-component sorption isotherms preliminarily show the reverse adsorption behavior in the low-pressure part, and the moderate heat of adsorption further confirms this performance and exhibits less energy consumption for regeneration. In addition, the purification effect for the C₃H₈/C₃H₆ mixture is evaluated by the IAST selectivity and transient breakthrough curves, and the GCMC calculation results reveal that the fascinating C₃H₈-trapping behavior mainly depends on the multiple C-H···π interactions. Moreover, because C₃H₆ is the desired target product, the interesting C₃H₈-selective adsorption behavior of <b>NUM-7</b> may provide its potential for one-step purification of C₃H₆, and this work can provide the method of developing C₃H₈-selective materials for the purification of C₃H₆.