ABSTRACT

A new recyclable and stable catalyst based on a Zr metal-organic framework, namely MIP-202 has been constructed through a simple post‐synthetic modification strategy as an extremely efficient and applied heterogeneous catalyst for Knoevenagel condensation reaction between benzaldehyde and ethyl cyanoacetate under mild reaction conditions. The principal purpose of this study is to reduce the amount of the protonated amine functional groups (NH₃⁺) in the pores of MIP-202 using the solvent assisted ligand exchange (SALE), in order to achieve an optimal structure to obtain higher efficiencies in Knoevenagel condensation reaction. The resultant catalyst is characterized via various techniques including PXRD, FT-IR, FE-SEM, EDX, BET, AAS, CHN, and TG analyses. The post-modified catalyst exhibited high catalytic performance with 90% efficiency, which is an enhanced activity compared to the pristine MIP-202 MOF, and also four recycling stability without a significant decrease in catalytic activity. Therefore, it was proved that the adjustment of functional groups is an effective method for the improvement of the reaction process. The catalytic mechanism has also been investigated.

摘要

一种基于 Zr 金属有机骨架的新型可回收且稳定的催化剂，即 MIP-202，是通过简单的合成后改性策略构建的，作为一种非常有效和实用的非均相催化剂，用于苯甲醛和氰基乙酸乙酯在温和反应下的 Knoevenagel 缩合反应状况。本研究的主要目的是减少质子化胺官能团 (NH ₃ ⁺) 在 MIP-202 的孔中使用溶剂辅助配体交换 (SALE)，以实现最佳结构，从而在 Knoevenagel 缩合反应中获得更高的效率。所得催化剂通过各种技术表征，包括 PXRD、FT-IR、FE-SEM、EDX、BET、AAS、CHN 和 TG 分析。后改性催化剂表现出高催化性能和 90% 的效率，与原始 MIP-202 MOF 相比具有更高的活性，并且在催化活性没有显着降低的情况下具有四次循环稳定性。因此，证明了官能团的调节是改进反应过程的有效方法。还研究了催化机制。