Study on catalytic performances of ZJU-64 series MOFs with acid-base sites for Knoevenagel condensation

Abstract

Metal-organic frameworks (MOFs) had unique advantages and attracted much attentions as catalysts for Knoevenagel condensation. In this work, ZJU-64 series MOFs (ZJU-64, ZJU-64-CH₃ and ZJU-64-NH₂) with acid-base sites were synthesized by solvothermal method and employed as heterogeneous catalysts for Knoevenagel condensation. The catalysts showed high catalytic yields in the reaction, which were directly affected by reaction temperature and time. The catalytic yield of ZJU-64 and ZJU-64-CH₃ at 75 °C for 1 hour was 96.92 % and 92.11 %, while that of ZJU-64-NH₂ was 97.76 %, displaying high catalytic yields. Furthermore, they remained activity in Knoevenagel condensation without significant degradation, indicating they were promising polyphase Knoevenagel condensation catalysts. ZJU-64-NH₂ showed excellent catalytic yield and revealed that the introduction of amino group could improve the catalytic performance of Zn-based MOFs.