A porous zirconium-based metal-organic framework with the potential for the separation of butene isomers

Abstract

By using a novel C₃-symmetrical tricarboxylate (4,4′,4′′-benzene-1,3,5-triyl-1,1′,1′′-trinaphthoic acid), a novel zirconium-based metal-organic framework ZJNU-30 was solvothermally synthesized and structurally characterized. Single-crystal X-ray structural analyses show that ZJNU-30 consists of Zr₆-based nodes connected by the organic linkers to form a (3,8)-connected network featuring the coexistence of two different polyhedral cages: octahedral and cuboctahedral cages with the dimensions of about 14 and 22 Å, respectively. Remarkably, ZJNU-30 is very stable when exposed to air for one month. More importantly, with a moderately high surface area, hierarchical pore structures and an aromatic-rich pore surface in the framework, ZJNU-30, after activation, exhibits a promising potential for the selective adsorptive separation of industrially important butene isomers consisting of cis-2-butene, trans-2-butene, 1-butene and iso-butene at ambient temperature. This separation was established exclusively by gas adsorption isotherms and simulated breakthrough experiments. To the best of our knowledge, this is the first study investigating porous metal-organic frameworks for butene-isomer separation.