Separation of Aromatic Hydrocarbons in Porous Materials

ABSTRACT: Industrial-scale thermal separation processes have contributed greatly to the rise in carbon dioxide emissions. Porous materials, such as metal-organic frameworks (MOFs), can potentially reduce these emissions by achieving nonthermal chemical separations through the physical adsorption of targeted species with high selectivity. Here, we report the synthesis of the channel-based MOFs NU-2000 and NU-2001, which are constructed from threedimensional (3D) linkers, to separate the industrially relevant xylene isomers under ambient conditions by leveraging sub-angstrom ngstrom differences in the sizes of each isomer. While the rotation of twodimensional (2D) linkers in MOFs often affords changes in pore apertures and pore sizes that are substantial enough to hinder separation efficiency, increasing the linker dimensionality from 2D to three-dimensional (3D) enables precise control of the MOF pore size and aperture regardless of the linker orientation, establishing this design principle as a broadly applicable strategy.

Automated summary

Industrial-scale thermal separation processes contribute to the increase in carbon dioxide emissions. Porous materials, like metal-organic frameworks (MOFs), can potentially reduce these emissions by achieving nonthermal chemical separations through the physical adsorption of target species. This study focuses on the synthesis of channel-based MOFs NU-2000 and NU-2001, which can separate industrially relevant xylene isomers under ambient conditions due to sub-angstrom size differences. By increasing the linker dimensionality from 2D to 3D, precise control of MOF pore size and aperture can be achieved, independent of linker orientation.