Ethylene/ethane separation in a stable hydrogen-bonded organic framework through a gating mechanism

• Published in: Nature chemistry 2021-10, Vol.13 (10), p.933-939
• Main Authors: Yang, Yisi, Li, Libo, Lin, Rui-Biao, Ye, Yingxiang, Yao, Zizhu, Yang, Ling, Xiang, Fahui, Chen, Shimin, Zhang, Zhangjing, Xiang, Shengchang, Chen, Banglin
• Format: Article
• Language: English
• Subjects: 639/638/298; 639/638/541/961; Acidity; Analytical Chemistry; Basicity; Biochemistry; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Energy efficiency; Ethane; Ethylene; Gas mixtures; Gating; Hydrogen; Hydrogen bonding; Inorganic Chemistry; Organic Chemistry; Physical Chemistry; Porous materials; Selectivity; Separation; Separation processes; Temperature requirements
• ISSN: 1755-4330; 1755-4349
• DOI: 10.1038/s41557-021-00740-z

Porous materials are very promising for the development of cost- and energy-efficient separation processes, such as for the purification of ethylene from ethylene/ethane mixture—an important but currently challenging industrial process. Here we report a microporous hydrogen-bonded organic framework that takes up ethylene with very good selectivity over ethane through a gating mechanism. The material consists of tetracyano-bicarbazole building blocks held together through intermolecular CN···H–C hydrogen bonding interactions, and forms as a threefold-interpenetrated framework with pores of suitable size for the selective capture of ethylene. The hydrogen-bonded organic framework exhibits a gating mechanism in which the threshold pressure required for guest uptake varies with the temperature. Ethylene/ethane separation is validated by breakthrough experiments with high purity of ethylene (99.1%) at 333 K. Hydrogen-bonded organic frameworks are usually not robust, yet this material was stable under harsh conditions, including exposure to strong acidity, basicity and a variety of highly polar solvents. Porous materials are promising candidates for the cost- and energy-efficient separation of ethylene and ethane from gas mixtures: an important but challenging industrial process. Now, a hydrogen-bonded organic framework has been reported that is stable under harsh conditions and can take up ethylene at practical temperatures—with very high selectivity over ethane—through a gating mechanism.