One-step ethylene production from a four-component gas mixture by a single physisorbent.

Cao, Jian-Wei; Mukherjee, Soumya; Pham, Tony; Wang, Yu; Wang, Teng; Zhang, Tao; Jiang, Xue; Tang, Hui-Juan et al. · Nat Commun · 2021

basic_science · Level V

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Abstract

One-step adsorptive purification of ethylene (C<sub>2</sub>H<sub>4</sub>) from four-component gas mixtures comprising acetylene (C<sub>2</sub>H<sub>2</sub>), ethylene (C<sub>2</sub>H<sub>4</sub>), ethane (C<sub>2</sub>H<sub>6</sub>) and carbon dioxide (CO<sub>2</sub>) is an unmet challenge in the area of commodity purification. Herein, we report that the ultramicroporous sorbent Zn-atz-oba (H<sub>2</sub>oba = 4,4-dicarboxyl diphenyl ether; Hatz = 3-amino-1,2,4-triazole) enables selective adsorption of C<sub>2</sub>H<sub>2</sub>, C<sub>2</sub>H<sub>6</sub> and CO<sub>2</sub> over C<sub>2</sub>H<sub>4</sub> thanks to the binding sites that lie in its undulating pores. Molecular simulations provide insight into the binding sites in Zn-atz-oba that are responsible for coadsorption of C<sub>2</sub>H<sub>2</sub>, C<sub>2</sub>H<sub>6</sub> and CO<sub>2</sub> over C<sub>2</sub>H<sub>4</sub>. Dynamic breakthrough experiments demonstrate that the selective binding exhibited by Zn-atz-oba can produce polymer-grade purity (>99.95%) C<sub>2</sub>H<sub>4</sub> from binary (1:1 for C<sub>2</sub>H<sub>4</sub>/C<sub>2</sub>H<sub>6</sub>), ternary (1:1:1 for C<sub>2</sub>H<sub>2</sub>/C<sub>2</sub>H<sub>4</sub>/C<sub>2</sub>H<sub>6</sub>) and quaternary (1:1:1:1 for C<sub>2</sub>H<sub>2</sub>/C<sub>2</sub>H<sub>4</sub>/C<sub>2</sub>H<sub>6</sub>/CO<sub>2</sub>) gas mixtures in a single step.