A chlorine-rich Zn-based metal-organic framework for efficient separation of C3H6/C2H4 and C2H6/C2H4

In the petrochemical industry, efficiently achieving one-step purification of ethylene (C 2 H 4 ) from propylene (C 3 H 6 ) or ethane (C 2 H 6 ) is a highly sought-after yet challenging task. Herein, we present a chlorine-rich Zn-based metal-organic framework (DMOF-1-Cl 2 ) that retains the essential topology of the parent DMOF-1 through the incorporation of 2,5-dichloroterephthalate linkers. The chlorine atoms within the square pores of DMOF-1-Cl 2 , due to their high electronegativity, serve as potential adsorption sites. Gas adsorptive experiments revealed its preferential adsorption of C 3 H 6 and C 2 H 6 over C 2 H 4 at different temperatures. Ideal adsorption solution theory calculation revealed that the selectivity of DMOF-1-Cl 2 for C 3 H 6 /C 2 H 4 and C 2 H 6 /C 2 H 4 reaches 20.8 and 2.2 at 313 K, respectively, outperforming its counterpart (DMOF-1-Br 2 ) and most previously reported adsorbents. Theoretical calculations indicated that the gas molecules are primarily distributed around the chlorine atoms with multiple interactions. Furthermore, dynamic breakthrough experiments fully demonstrated the actual potential for achieving one-step purification of polymer-grade C 2 H 4 , in which DMOF-1-Cl 2 displayed high productivity of 206.1 and 31.6 L kg −1 from C 3 H 6 /C 2 H 4 (2/5, v/v) and C 2 H 6 /C 2 H 4 (1/9, v/v), respectively. Despite the fact that the yield of C 2 H 4 separation from C 2 H 6 /C 2 H 4 mixtures is not extremely high, it still remains at a satisfactory level, demonstrating the practical value and potential of DMOF-1-Cl 2 for industrial applications.