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

Abstract

Fabricating easily available adsorbents with highly selective adsorption separation performance for propylene/propane mixtures is a desirable and energy-efficient way to produce high-purity propylene in the petrochemical industry. In this study,...

A new honeycomb MOF for C2H4purification and C3H6enrichment by separating methanol to olefin products

“…The capacity of 216.4 cm 3 g −1 for C 3 H 6 in Mn-dtzip is close to that of the very excellent material spe-MOF (236.9 cm 3 g −1 ), 30 and significantly higher than that reported for representative C 3 H 6 -adsorptive MOFs, such as Mg-MOF-74 (174 cm 3 g −1 ), 39 Ni-MOF-74 (118.8 cm 3 g −1 ), 40 UPC-21 (116.2 cm 3 g −1 ), 41 and CoNi-pyz (91.9 cm 3 g −1 ). 42 Under a low pressure of 20 kPa, the adsorption capacity of C 3 H 6 was still high at 117.9 cm 3 g −1 at 298 K. In sharp contrast, the significantly low amount of C 2 H 4 gas was adsorbed, and the loading ratio of C 3 H 6 : C 2 H 4 was 7.0. Meanwhile, under 5 kPa, this ratio reached 8.7.…”

Synthesis of Hofmann-based metal–organic frameworks incorporating a bis-pyrazole linker for various gas separations

“…Of the published materials, the current benchmark performance for C 3 uptake by a Hofmann-like material is found in CoNi-pyz (pyz = pyrazine) which adsorbs 4.10 and 3.9 mmol g −1 for C 3 H 6 and C 3 H 8 , respectively, with an IAST selectivity for the separation at 3.5 (at 1 bar, 298 K). 20 The isostructural CoNi-piz framework, where piz = piperazine, recorded a lower uptake of 2.33 and 1.23 mmol g −1 for C 3 H 6 and C 3 H 8 , respectively, however the calculated IAST for the separation was 15. 20 While these examples have higher uptake capacity and IAST values than the materials reported here, both [Co(H 2 mdp)(Ni(CN) 4 )] and [Fe(H 2 mdp)(Ni(CN) 4 )] have greater uptake ratios between the C 3 hydrocarbons than CoNi-pyz .…”

“…12–14 Despite their history, Hofmann frameworks were not routinely considered for gas separations until 2013, when a wide-screen of a range of Hofmann frameworks for their CO 2 and N 2 adsorption abilities was published. 15 To date, several studies examining Hofmann frameworks for gas separation have been limited to select gas pairings, including C 2 H 2 /CO 2 , 16,17 Kr/Xe, 18,19 C 3 H 6 /C 3 H 8 , 20,21 various xylenes and hydrogen isotopes. 22,23 A recent notable example is ZJU-74 , {Co(pyz)[Ni(CN) 4 ]} (pyz = pyrazine), which showed standout selectivity for C 2 H 2 over CO 2 , C 2 H 4 and CH 4 , with the 2D cyano-layers creating a ‘sandwich-like’ binding pocket for C 2 H 2 to enable high affinity and benchmark capacity (2.19 mmol g −1 at 0.01 bar).…”

Preparation of an interpenetrating bimetal metal–organic framework via metal metathesis used for promoting gas adsorption

“…The materials’ structural stability, reusability and energy-saving regeneration should also be considered for industrial implementation besides their adsorption performance. 57 As shown in Fig. 7b, S4b, S5b and S6b,† the adsorption performance of MIL-126(Cr/Sc) can be regenerated by applying dynamic vacuum at room temperature for 30 min.…”