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

Abstract

The propane (C 3 H 8 )-trapping adsorption behavior is considered as a potential performance to directly produce highpurity 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 lowpressure 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 .

Direct Visualization of Supramolecular Binding and Separation of Light Hydrocarbons in MFM-300(In)

“…The spectrum of ethylene-loaded MFM-300(In) reveals a broad peak at low energy transfer (below 25 meV), which is characteristic of almost free rotational motion around the C=C axis. A peak is observed at around 100 meV, assigned to the in-plane rocking mode of −CH 2 34 in both the difference spectrum and that of the solid ethylene. In the spectra for ethane-loaded MFM-300(In), a broad peak is observed below 25 meV, corresponding to the almost free rotational mode around the C–C axis.…”

“…Single-component adsorption isotherms reveal that MFM-300(In) has a distinct binding affinity to C 3 H 4 over C 3 H 6 and C 3 H 8 and to C 2 H 6 over C 2 H 4 over a wide range of temperatures from 273 to 303 K. The uptake of C 3 hydrocarbons exhibits steep adsorption isotherms at low pressure, with C 3 H 4 , C 3 H 6 , and C 3 H 8 reaching 73 to 87% of their total adsorption capacity at 1 bar at a pressure of 100 mbar; it is notable that these isotherms reach a plateau at 400 mbar at 293 K. The total adsorption capacity of these gases at 1 bar and 293 K follows the degree of unsaturation of the gas, with C 3 H 4 , C 3 H 6 , and C 3 H 8 reaching 6.3, 5.4, and 4.8 mmol g –1 , respectively, comparable with the highest values reported for MOF materials in the literature. 34 , 35 …”

Rapid Screening of Metal–Organic Frameworks for Propane/Propylene Separation by Synergizing Molecular Simulation and Machine Learning

“…16 An ultramicroporous Mnbased MOF (NUM-7) with electronegative aromatic rings was reported to be C 3 H 8 -selective in a low-pressure range. 17 Among three MIL-88 derived MOFs by using a pore-spacepartition strategy, CPM-734c with an abundant aromatic surface and optimal pore size was found to selectively separate C 3 H 8 from C 3 H 6 . 18 Currently, over 100 000 MOFs have been synthesized, and it is highly desired to identify high-performance MOFs for the industrially important C 3 separation.…”

“…With dense electronegative binding sites, a polycatenated molecular cage in a MOF [Ni­(bpe) 2 (WO 4 )] exhibited preferential C 3 H 8 adsorption and recorded C 3 H 8 /C 3 H 6 selectivity . An ultramicroporous Mn-based MOF (NUM-7) with electronegative aromatic rings was reported to be C 3 H 8 -selective in a low-pressure range . Among three MIL-88 derived MOFs by using a pore-space-partition strategy, CPM-734c with an abundant aromatic surface and optimal pore size was found to selectively separate C 3 H 8 from C 3 H 6 …”

Linker micro-regulation of a Hofmann-based metal–organic framework for efficient propylene/propane separation

“…As an alternative, the separation of C 3 H 6 /C 3 H 8 may also be achieved through differential diffusion rates of the two components in the so-called kinetic separation, but few examples reported to date have shown efficient separation performance under dynamic conditions. [27][28][29][30] In a further approach, in order to directly obtain high-purity C 3 H 6 , some C 3 H 8 -selective adsorbents have been investigated for C 3 H 8 / C 3 H 6 separation, 31,32 but as the two components share the same alkyl moiety (-CH 3 group), achieving strongly C 3 H 8 -selective adsorption remains difficult. Thus, improved separation efficiency is urgently needed.…”