Ambient aqueous-phase synthesis of covalent organic frameworks for degradation of organic pollutants†

Abstract

Herein we report the first case of a β-ketoenamine based Michael addition–elimination reaction as well as ambient aqueous-phase synthesis of highly crystalline COF materials.

Abstract

The development of a mild, low cost and green synthetic route for covalent organic frameworks (COFs) is highly desirable in order to open the door for practical uses of this new family of crystalline porous solids. Herein, we report a general and facile strategy to prepare a series of microporous or mesoporous COFs by a β-ketoenamine based Michael addition–elimination reaction in aqueous systems at ambient temperature and pressure. This synthesis method not only produces highly crystalline and porous COFs, but also can be carried out with a high reaction rate (only 30 min), high yields (as high as 93%) and large-scale preparation (up to 5.0 g). Furthermore, an Fe( ii)-doped COF shows impressive performance in the oxidative degradation of organic pollutants in aqueous medium. This research thus provides a promising pathway to large-scale green preparation of COFs and their potential application in environmental remediation.

Notes

†Electronic supplementary information (ESI) available: Procedure for the preparation of COFs, SEM images, FT-IR spectra, solid-state ¹³C NMR spectra, TGA analysis, stability test, PXRD patterns and structures, unit cell parameters and fractional atomic coordinates, and BET plots. See DOI: 10.1039/c9sc03725j