One-Step Ethylene Purification from Ternary Mixtures in a Metal-Organic Framework with Customized Pore Chemistry and Shape

Adsorptive separation is an energy-efficient technology for the separation of C2 hydrocarbons. However, it remains a critical problem to directly produce high-purity C2H4 from ternary C2H2/C2H4/C2H6 mixtures by simultaneously trapping C2H2 and C2H6. Herein, we report the one-step C2H4 purification from the ternary mixture by a metal-organic framework Zn(ad)(int) (ad=adeninate; int=isonicotinate). The material combines dense heterocyclic rings and accessible uncoordinated O atoms as strong binding sites for C2H6 and C2H2. Its spindle-like cage exhibits an interesting shape matching with the targeted molecules, affording Zn(ad)(int) not only high separation selectivity for C2H6/C2H4 and C2H2/C2H4, but also excellent gas capacity. Breakthrough experiments show that polymer-grade C2H4 can be separated from the ternary mixtures with a record productivity of 1.43 mmol g(-1). In situ powder X-ray diffraction and Fourier transform infrared spectrum analyses further provide deep insights into the separation mechanism.

Automated summary

In this study, a metal-organic framework Zn(ad)(int) was reported for the one-step purification of C2H4 from ternary mixtures. The material utilizes dense heterocyclic rings and accessible uncoordinated O atoms as binding sites, achieving high selectivity for C2H6 and C2H2 separation and excellent gas capacity. Breakthrough experiments demonstrate that polymer-grade C2H4 can be separated with a record productivity.