Revving Up a Designed Copper Catecholate Porous Organic Polymer for Its Potent Ethylene Adsorption than Ethane

초록

The potential to produce high-purity C2H4 has made ethylene-selective adsorbents for ethane (C2H6)/ethylene (C2H4) gas mixture separation appealing as viable substitutes for traditional cryogenic distillation. In this aspect, porous organic polymers (POPs) are anticipated to become the next-generation potential adsorbent due to their easily customizable functions and functional sites suitable for gas separation. This article reports the selective C2H4 adsorption over C2H6 using microporous copper(I)-coordinated POP (Cu@Di-POP) via fine-tuning of the pi complexation and pore size. The specially designed adsorbent has the ideal pore size and coordinated Cu(I) ions to form pi-complexation with C2H4 molecules, which enabled it to adsorb C2H4 (at 1 bar, 24.9, 18.9, and 13.4 cm(3) g(-1) at 273, 298, and 323 K, respectively) while significantly reducing C2H6 adsorption (at 1 bar, 16.9, 12.7, and 8.8 cm(3) g(-1) at 273, 298, and 323 K, respectively). At 1 bar, Cu@Di-POP exhibited IAST selectivities of 6.09, 5.60, and 4.13 for C2H4/C2H6 at 273, 298, and 323 K, respectively, suggesting its C2H4 selective behavior, which was further confirmed from the experimental breakthrough measurement. Furthermore, the computational studies carried out with density functional theory highlighted an enhanced charge distribution leading to d pi-p pi conjugation between C2H4 pi-electrons and Cu d-electrons, thereby showing a relatively higher interaction energy of -37.23 kcal/mol with C2H4 as compared to -16.06 kcal/mol with C2H6 gas molecules.

키워드