Microporous Metal–Organic Framework with a Completely Reversed Adsorption Relationship for C₂ Hydrocarbons at Room Temperature

Abstract

As a new type of porous material, metal–organic frameworks (MOFs) have been widely studied in gas adsorption and separation, especially in C2 hydrocarbons. Considering the stronger interaction between the unsaturated molecules and the metal sites, and the smaller molecular size of unsaturated molecules, the usual relationship of affinities and adsorption capacities among C2 hydrocarbons in most common MOFs is C2H2 > C2H4 > C2H6. Herein, a unique microporous metal–organic framework, NUM-7a (activated NUM-7), with a completely reversed adsorption relationship for C2 hydrocarbons (C2H6 > C2H4 > C2H2) has been successfully synthesized, which breaks the traditional concept of the adsorption relationship of MOFs for C2 hydrocarbons. Based on this unique adsorption relationship, a green and simple one-step separation purification for a large amount of C2H4 can be expected to be achieved through the selective adsorption of C2H6. In addition, NUM-7a also shows good selectivities in C2H2/CO2 and CO2/CH4.

A Microporous Metal‐Organic Framework with Channels Constructed from Nonpolar Aromatic Rings for the Selective Separation of Ethane/Ethylene Mixtures

“…At 100 kPa, Co-TATB exhibits a selectivity of 1.62 and 1.48 for 50/50 (v/v) C 2 H 6 /C 2 H 4 mixtures 273 K and 296 K, respectively (Figure 2d). The selectivity is comparable with other porous materials, such as NUM-7a (1.76), [44] JNU-2 (1.6), [45] and MAF-123-Cu (1.73) [46] (Table S3).…”

A Series of Mesoporous Metal‐Organic Frameworks with Tunable Windows Sizes and Exceptionally High Ethane over Ethylene Adsorption Selectivity

“…The corresponding selectivity factors for MOFs reported up to now at ambient conditions are typically quite low (S < 3) with MAF-49 being the only exception with appreciable selectivity S = 9.0. [22,[28][29][30][31][32][33][34][42][43][44][45][46][47][48][49][50][51][52][53][54][55] Theb est C 2 H 6 /C 2 H 4 absorption selectivity obtained for NIIC-20-Bu at similar conditions (S = 15.4) is 1.7 times higher than that for MAF-49 and greatly surpasses the majority of other literature results reported so far (Table S9). Other than the adsorption selectivity,the adsorption uptake is an equally important parameter for an adsorbent for gas separation applications.I nt his regard, am ore accurate evaluation of porous materials should be revealed from the selectivity vs.uptake plot.…”

Designer Metal–Organic Frameworks for Size‐Exclusion‐Based Hydrocarbon Separations: Progress and Challenges

“…A number of MOFs have demonstrated the capability to separate acetylene and ethylene through thermodynamically driven mechanism. [53,54] MOFs with OMSs could provide specific metal-π interaction and they are capable of differentiating alkynes and alkenes based on the strength of adsorption affinity. ) and 4,4-dipyridyl or its derivatives.…”