The Efficient Knoevenagel Condensation Promoted by Bifunctional Heterogenized Catalyst Based Chitosan-EDTA at Room Temperature

An efficient heterogeneous catalyst-based low molecular weight chitosan (LWC) modified with EDTA groups were prepared and applied as a bifunctional heterogenized catalyst in the Knoevenagel Condensation reaction, promoting fast reactions between malononitrile and aldehydes or isatins at room temperature. Chitosan-EDTA (LWC-EDTA) catalysts were characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA/DTA), powder X-ray diffraction (XRD). UV-Vis absorption spectrophotometry showed that the functionalization of chitosan with EDTA for 72 h promotes the most significant modification of the matrix surface compared to the others applied, reflecting shorter reaction times. The reactions using the LWC-EDTA-72 catalyst present excellent isolated yields (78-98%) in short reaction times (0.50-120 min) for differents Knoevenagel compounds. Additionaly, the catalyst was easily recovered and reused up to six times without significant losses of its catalytic activity. [GRAPHICS] .

Automated summary

In this study, an efficient heterogeneous catalyst based on low molecular weight chitosan modified with EDTA groups was prepared and applied in the Knoevenagel Condensation reaction, demonstrating fast reactions with excellent yields at room temperature. The catalyst showed significant surface modification and short reaction times, and could be easily recovered and reused without significant loss of catalytic activity.