A Noncovalent π-Stacked Dual-Pore Molecular Crystal for Ethanol/Water and Benzene/Methanol Azeotrope Separation.

Separation of ethanol/water or benzene/methanol azeotrope mixtures presents significant challenges, not only due to the limitations of conventional distillation techniques but also because of the constraints in developing and utilizing of new generation adsorbents. Porous organic molecular frameworks constructed via noncovalent π-interactions are emerging as novel adsorbents with vast potential in gas adsorption and molecular separation. Herein, we report a permanent two-dimensional porous structure, namely TDTBA-1, which consists of two different kinds of pores through π-stacking of a single organic molecule with highly Td symmetry. Activated TDTBA-1 exhibits excellent hydrophobicity, thermal stability, recoverability and high selectivity for ethanol over water, and benzene over methanol. Therefore, activated TDTBA-1 can be used as an efficient stationary phase for the separation of ethanol/water and benzene/methanol azeotropes by high-resolution gas chromatography.