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

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-CF3 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 C2H2 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.