Covalent organic framework crystallization using a continuous flow packed-bed reactor

Abstract

Flow systems enable in-line synthesis and processing of organic materials in a continuous reaction pathway, which is advantageous for high-throughput and scale-up. In this work, a highly crystalline TAPB-OHPDA covalent organic framework (COF) was directly crystallized under continuous flow conditions in as little as 30 minutes. Brunauer–Emmett–Teller (BET) surface analysis reveals high surface areas greater than 1700 m² g⁻¹ can be afforded in 2 hours, resulting in a 36× faster processing time compared to a majority of other reported solvothermal methods. Additionally, the crystalline COF material was also washed with solvent in flow to reduce the required post-processing burden typically performed iteratively during purification and activation. The results presented herein provide foundational knowledge for COF syntheses under packed-bed flow conditions and reveal an opportunity to accelerate the formation and processing of highly crystalline COF materials.