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

The propane (C 3 H 8 )-trapping adsorption behavior is considered as a potential performance to directly produce high-purity propylene (C 3 H 6 ). Herein, we report an ultramicroporous Mn-based metal–organic framework ( NUM-7 ) with a reverse C 3 H 8 -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 C 3 H 8, 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 C 3 H 8 /C 3 H 6 mixture is evaluated by the IAST selectivity and transient breakthrough curves, and the GCMC calculation results reveal that the fascinating C 3 H 8 -trapping behavior mainly depends on the multiple C–H···π interactions. Moreover, because C 3 H 6 is the desired target product, the interesting C 3 H 8 -selective adsorption behavior of NUM-7 may provide its potential for one-step purification of C 3 H 6, and this work can provide the method of developing C 3 H 8 -selective materials for the purification of C 3 H 6 .