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Molecular Sieving of Ethane from Ethylene through the Molecular Cross‐Section Size Differentiation in Gallate‐based Metal–Organic Frameworks
Author(s) -
Bao Zongbi,
Wang Jiawei,
Zhang Zhiguo,
Xing Huabin,
Yang Qiwei,
Yang Yiwen,
Wu Hui,
Krishna Rajamani,
Zhou Wei,
Chen Banglin,
Ren Qilong
Publication year - 2018
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201808716
Subject(s) - gallate , ethylene , chemistry , metal organic framework , selectivity , metal , adsorption , zigzag , ethylene glycol , chemical engineering , nuclear chemistry , organic chemistry , catalysis , geometry , mathematics , engineering
Abstract Purification of C 2 H 4 from an C 2 H 4 /C 2 H 6 mixture, one of the most important while challenging industrial separation processes, is mainly through energy‐intensive cryogenic distillation. Now a family of gallate‐based metal–organic framework (MOF) materials is presented, M‐gallate (M=Ni, Mg, Co), featuring 3D interconnected zigzag channels, the aperture sizes of which (3.47–3.69 Å) are ideally suitable for molecular sieving of ethylene (3.28×4.18×4.84 Å 3 ) and ethane (3.81×4.08×4.82 Å 3 ) through molecular cross‐section size differentiation. Co‐gallate shows an unprecedented IAST selectivity of 52 for C 2 H 4 over C 2 H 6 with a C 2 H 4 uptake of 3.37 mmol g −1 at 298 K and 1 bar, outperforming the state‐of‐the‐art MOF material NOTT‐300. Direct breakthrough experiments with equimolar C 2 H 4 /C 2 H 6 mixtures confirmed that M‐gallate is highly selective for ethylene. The adsorption structure and mechanism of ethylene in the M‐gallate was further studied through neutron diffraction experiments.