A novel anion-pillared metal-organic framework for highly efficient separation of acetylene from ethylene and carbon dioxide†

Separation of acetylene (C2H2) from ethylene (C2H4) and carbon dioxide (CO2) is of great importance in the petrochemical industry but remains a daunting challenge due to their very similar sizes and physical properties. Although a number of porous materials have been developed as promising adsorbents for either C2H2/C2H4 or C2H2/CO2 separation, few materials exhibit simultaneously high selectivities for both gas mixtures. Herein, we report the use of a four-connected N-donor organic linker to construct a novel water-stable SIFSIX-type material, [Cu(TPB)SiF6](n) (termed ZJU-280, TPB = 1,2,4,5-tetra(pyridin-4-yl)benzene). This material features suitable rhombic pores and functional surfaces to interact optimally with C2H2 molecules, affording high C2H2 capture capacity and simultaneously high C2H2/CO2 (18.1) and C2H2/C2H4 (44.5) selectivities under ambient conditions. Theoretical calculations indicate that the suitable rhombic pores and functional sites can provide a multipoint binding environment to not only preferentially interact with C2H2 but also enable the dense packing of C2H2 molecules within the framework. Actual breakthrough experiments demonstrate that ZJU-280a can efficiently separate C2H2 from C2H2/CO2 (50/50, v/v) and C2H2/C2H4 (1/99 and 50/50) mixtures, respectively.

Automated summary

Researchers have developed a novel water-stable SIFSIX-type material ZJU-280 using a four-connected N-donor organic linker, which features suitable rhombic pores and functional surfaces for high C2H2 adsorption capacity and selectivities for both C2H2/CO2 (18.1) and C2H2/C2H4 (44.5) under ambient conditions. Actual breakthrough experiments demonstrate the efficient separation of C2H2 from C2H2/CO2 and C2H2/C2H4 mixtures using ZJU-280a.