Selective Adsorption and Separation of Xylene Isomers and Benzene/Cyclohexane with Microporous Organic Polymers POP-1.

Currently, the separation of chemical substances with analogous chemical structures and physical properties is still a great challenge. In this work, triptycene-like microporous organic polymers (MOPs), POP-1, was synthesized via choosing 1,4-dimethoxybenzene (DMB) and triptycene as external crosslinkers and building blocks, respectively, and POP-1 was employed to separate xylene isomers and benzene(Bz)/cyclohexane(Cy). Results show that POP-1 has a higher uptake for m-Xylene (0.29 g/g) and Bz (1.02 g/g); more intriguingly, their complete separation can be realized within 0.6 minutes using a column packed with POP-1. The interaction between POP-1 networks and adsorbates was also investigated using theoretical (density functional theory, DFT, together with non-covalent interaction analysis, NCI) and experimental (inverse gas chromatography, IGC) approaches. Especially, both results present a good agreement, that is, weak interactions, such as CH/π interactions, play a dominant role in defining the separation performance of POP-1 for xylene isomers and Bz/Cy mixtures. Our findings suggest that MOPs may open up a new route for separating the chemicals that are similar in structures and size.