One-Step C2 H4 Purification from Ternary C2 H6 /C2 H4 /C2 H2 Mixtures by a Robust Metal-Organic Framework with Customized Pore Environment

Angew Chem Int Ed Engl. 2022 Jul 11;61(28):e202205427. doi: 10.1002/anie.202205427. Epub 2022 May 12.

Abstract

One-step C2 H4 purification from ternary C2 H6 /C2 H4 /C2 H2 mixtures by a single adsorbent is of great industrial significance, but few adsorbents achieve this separation. Herein, we report a robust metal-organic framework (MOF) that possesses methyl-decorated nonpolar pores and shows one-step C2 H4 purification (purity >99.9 %) from binary C2 H6 /C2 H4 mixtures and ternary C2 H6 /C2 H4 /C2 H2 mixtures. The methyl groups in pores provide a suitable pore environment to simultaneously enhance the adsorption capacity for C2 H2 and C2 H6 compared to C2 H4 . Simulations revealed the multiple interactions between C2 H6 or C2 H2 molecules and the pore wall, while the interactions with C2 H4 molecules are weak and also unfavorable due to the repulsion from methyl groups in pores. The MOF displays high C2 H6 and C2 H2 uptakes and benchmark C2 H6 /C2 H4 selectivity (2.2), surpassing all of the reported MOFs for one-step C2 H4 purification from ternary C2 H6 /C2 H4 /C2 H2 mixtures.

Keywords: Crystal Structures; Ethylene Purification; Gas Adsorption; Hydrocarbon Separation; Metal-Organic Frameworks.