Efficient Synthesis of Branched Polyamine Based Thermally Stable Heterogeneous Catalyst for Knoevenagel Condensation at Room Temperature

In this paper, a new convenient strategy for the synthesis of polyethylenimine functionalized Si-MCM-41 grafted on surface modified graphene oxide has been developed. The as-synthesised catalyst exerts good catalytic activity and reusability toward Knoevenagel condensation of different substituted aromatic aldehydes with malononitrile and ethyl cyanoacetate. Moreover, it shows remarkable thermal stability. The physicochemical characteristics of the catalyst as probed by FTIR, XRD, N2 sorption isotherms, TGA, XPS, FESEM, TEM, and solid state 13C NMR analyses, were discussed to get an idea about the catalytic mechanism of Knoevenagel condensation.