A robust Th-azole framework for highly efficient purification of C₂H₄ from a C₂H₄/C₂H₂/C₂H₆ mixture

Separation of C₂H₄ from C₂H₄/C₂H₂/C₂H₆ mixture with high working capacity is still a challenging task. Herein, we deliberately design a Th-metal-organic framework (MOF) for highly efficient separation of C₂H₄ from a binary C₂H₆/C₂H₄ and ternary C₂H₄/C₂H₂/C₂H₆ mixture. The synthesized MOF Azole-Th-1 shows a UiO-66-type structure with fcu topology built on a Th₆ secondary building unit and a tetrazole-based linker. Such noticeable structure, is connected by a N,O-donor ligand with high chemical stability. At 100 kPa and 298 K Azole-Th-1 performs excellent separation of C₂H₄ (purity > 99.9%) from not only a binary C₂H₆/C₂H₄ (1:9, v/v) mixture but also a ternary mixture of C₂H₆/C₂H₂/C₂H₄ (9:1:90, v/v/v), and the corresponding working capacity can reach up to 1.13 and 1.34 mmol g⁻¹, respectively. The separation mechanism, as unveiled by the density functional theory calculation, is due to a stronger van der Waals interaction between ethane and the MOF skeleton.