Pore Aperture Control Toward Size-Exclusion-Based Hydrocarbon Separations

Metal-organic frameworks (MOFs) have been proposed as a promising material for non-thermal chemical separations owing to their high structural diversity and tunability. Here, we report the synthesis of a zinc-based MOF containing a three-dimensional (3D) linker, bicyclo[2.2.2]octane-1,4-dicarboxylic acid, with high thermal stability towards the separation of hexane isomers. The incorporation of the 3D linker enhances the structural stability and provides well-defined pore apertures/channels with sub-angstrom ngstrom precision. This precision allowed for the separation of similarly sized hexane isomers based on subtle differences in their kinetic diameters. Multi-component liquid phase batch experiments confirmed the separation of hexanes mixture into linear, monobranched, and dibranched isomers. This work represents a significant milestone in the construction of stable Zn-based MOFs and the incorporation of 3D linkers as a potential solution to challenging separations.

Automated summary

We report the synthesis of a zinc-based MOF containing a three-dimensional (3D) linker, which shows high thermal stability for the separation of hexane isomers. The incorporation of the 3D linker enhances the structural stability and provides precise pore apertures/channels. This work represents a significant milestone in the construction of stable Zn-based MOFs and the incorporation of 3D linkers for challenging separations.