Synthesis And Catalytic Properties Of Br(?)nsted Acid-based Covalent Organic Frameworks

Covalent organic frameworks(COFs)are crystalline porous organic materials assembled from light elements(such as C,H,O,N,B,etc.)through covalent bonds.COFs have attracted more and more attention due to their advantages of low density,large specific surface area,high order of pores,adjustable function and high porosity.So far,COFs have been extensively studied in the fields of gas separation and storage,catalysis,sensing,proton conduction,optoelectronics,etc.,and have good development prospects.This paper studies the synthesis of two types of COFs and their application in catalysis.The research content is mainly divided into the following two parts:Ⅰ.Designed and synthesized a class of bifunctional COFs combined with covalent organic framework and Br(?)nsted acid.Among them,TAPB-DMTP-PA-COF is connected by quinoline-4-carboxylic acid,which has good stability.Therefore,it can be used as a heterogeneous catalyst to efficiently catalyze the one-pot series deacetalization-Knoevenagel reaction under solvent-free conditions,and obtain a 99% GC yield.Moreover,TAPB-DMTP-PA-COF can be reused at least 15 times without losing its catalytic activity.Our work not only provides a synthetic strategy to obtain stable COFs,but also provides the possibility for the development of more novel COFs-based bifunctional catalysts.Ⅱ.A case of Br(?)nsted acid TFPPY-BDU-COF with high crystallinity was synthesized by solvothermal method using 1,3,6,8-tetrakis(4-formylphenyl)pyrene(TFPPY)and 1,4-diphenyl urea(BDU).TFPPY-BDU-COF characterized by PXRD,FT-IR,NMR,etc.At the same time,catalytic active sites of Br(?)nsted acid in the TFPPY-BDU-COF framework,it was used as a heterogeneous catalyst to catalyze Friedel-Crafts reactions,and yields as high as 99% were obtained.Moreover,TFPPY-BDU-COF is easy to separate and recover,and can be reused 10 times without losing its catalytic activity.