Chitosan as a biodegradable heterogeneous catalyst for Knoevenagel condensation between benzaldehydes and cyanoacetamide
Nagaraj Anbu, R. Uma Maheswari, Elamathi Vimali, Perumal Varalakshmi, Amarajothi Dhakshinamoorthy
Abstract
A natural biopolymer chitosan is being employed as heterogeneous solid base catalyst for the Knoevenagel condensation reaction between benzaldehydes and cyanoacetamide under mild reaction conditions. This reaction offers the direct synthesis of condensation product with two functional groups that can readily be functionalized. The biopolymer is used for five cycles with no decrease in activity and hot filtration test proves heterogeneity of the reaction. Some of the salient features of this strategy include biodegradability of catalyst, high catalyst stability, mild reaction conditions and wide substrate scope. The structural integrity is retained even after repeated cycles as evidenced by powder X-ray diffraction (XRD).