Postsynthetically modified hydrophobic covalent organic frameworks for enhanced oil/water and CH4/C2H2 separation

The superhydrophobic quinoline-linked material COF-Q-CF 3 was prepared by COFs and enamides via an aza-Diels-Alder reaction for the first time. This material not only retained its crystallinity and porosity but also displayed dramatically enhanced oil/water and CH 4 /C 2 H 2 separation performance. • The imine-linked COF-LZU1 was modified by aza-Diels-Alder reaction with enamides. • The as-prepared COF-Qs retain good crystallinity, morphology and porosity. • The as-prepared COF-Q-CF 3 exhibits ultra-high oil/water separation performance. • The as-prepared COF-Q-CF 3 has capability for separation C 2 H 2 from CH 4 . Porous hydrophobic materials are very attractive for practical use. Reported herein is a facile strategy that transforms imine-linked covalent organic frameworks (COFs) into porous quinoline-linked aromatic frameworks by an aza-Diels-Alder reaction of COF-LZU1 and enamides for the first time. The chemically modified superhydrophobic COF-Q-CF 3 not only retained crystallinity and porosity, but also displayed dramatically enhanced oil adsorption as well as water-in-oil emulsion separation performance with excellent separation efficiency. Additionally, it also exhibited selective C 2 H 2 adsorption at 273 K and 1 bar. This protocol constitutes a step for expanding the scope of COF applications in oil spill remediation and separation.