High C2H6/C2H4 selectivity via incorporation of dense methyl groups into a stable Zr-based MOF with cavity-like pores

The development of efficient adsorbents for C2H6/C2H4 separation is an important and challenging issue for the economical production of high-purity ethylene, a valuable precursor for the petrochemical industry. We developed an efficient adsorbent for C2H6/C2H4 separation by incorporating highly dense methyl groups into a highly stable UiO-66 framework with "cavity-like" pores. Remarkably, UiO-66-2Me exhibited large C2H6 uptake at 1 bar (2.15 mmol/g) and significantly high C2H6/C2H4 IAST selectivity (2.93), which is one of the highest values reported. From a combined experiments and computational study, we verified that the observed high selectivity was originated from the specific interaction between C2H6 and multiple methyl groups in the cavity-like pores. Moreover, UiO-66-2Me showed high C2H6/C2H4 selectivity (2.05) even under the dynamic mixture flow condition, easy regeneration and good hydrothermal and thermal stabilities. These results suggest that incorporating highly dense methyl groups into a stable MOF with cavity-like pores is a promising method for developing an efficient adsorbent for C2H6/C2H4 separation.