A robust ethane-trapping metal-organic framework for efficient purification of ethylene

Owing to the similar physicochemical properties between ethane (C2H6) and ethylene (C2H4), obtaining polymerization-grade C2H4 (>= 99.95% pure) is still tricky problem in the petrochemical industry. Here, we report a robust scandium-based metal-organic framework (ScBPDC), which is connected by oxygen-rich phenyl ligand with exceptionally high thermal stability (up to 873 K) and capacity of C2H6 (4.94 mmol/g at 100 kPa and 283 K), exhibiting superior separation performance of C2H6/C2H4 mixture (the IAST selectivity is up to 1.7 at 283 K). Importantly, ScBPDC can produce 8.96 L/kg C2H4 with >= 99.99% purity while the C2H4/C2H6 (50:50, v/v) as the mixture injection and the low isosteric heat of ScBPDC (16.4 kJ/mol for C2H6) validates the facility of adsorbent regeneration. Furthermore, theoretical calculations demonstrate the C2H6 molecules are trapped in the nonpolar pore surface via C-HMIDLINE HORIZONTAL ELLIPSIS pi and C-HMIDLINE HORIZONTAL ELLIPSISO interactions between multiple hydrogen atoms of C2H6 and the host framework.

Automated summary

This study reports a robust scandium-based metal-organic framework connected by an oxygen-rich phenyl ligand, which shows high adsorption capacity for C2H6 and superior selectivity for separating C2H6/C2H4 mixture. Theoretical calculations demonstrate the trapping of C2H6 molecules in the nonpolar pore surface via specific interactions.