A Flexible Metal-Organic Framework for the Removal of Propyne from Propylene

Abstract

Efficient removal of propyne impurities from propylene is essential for producing high-purity propylene. In this study, we utilize the flexible metal-organic frameworks (MOFs) material, MOF-508, for C₃H₄/C₃H₆ separation. Propyne (C₃H₄) induces a “Gate-opening” effect in MOF-508, transitioning it from a narrow-pore phase to a large-pore phase at low pressure. In contrast, propylene (C₃H₆) only triggers this effect at a higher pressure of 0.55 bar. Notably, at 298 K and 0.5 bar, MOF-508 adsorbs 71.9 cm³/g of C₃H₄, compared to just 7.9 cm³/g of C₃H₆. This selective adsorption significantly enhances C₃H₄/C₃H₆ separation (50/50, v/v), as further demonstrated by dynamic breakthrough experiments.