Remarkable Catalytic Activity of Superparamagnetic Retrievable Mg-Doped Ferrite Nanoparticles for Knoevenagel Condensation

Abstract

The current study deals with the design and application of a magnetically recoverable Mg-doped ferrite nanocatalyst (MgFe₂O₄) for the microwave-assisted Knoevenagel condensation of aldehydes with ethyl cyanoacetate. Conventional catalysts based on Fe₃O₄ usually suffer from a number of disadvantages, including moderate activity, limited recyclability, and reduced stability in green reaction conditions. In this respect, a series of Mg²⁺-doped ferrites were prepared by an easy co-precipitation route to modulate the acid–base balance and surface properties. XRD, FTIR, FESEM, TEM, UV–Vis, and VSM characterized the obtained nanosized spinel MgFe₂O₄ with increased surface area and magnetic separability. Under MW irradiation, the MgFe₂O₄ catalyst displayed as high as 70% yield in 10 min and was more active than the corresponding undoped Fe₃O₄ counterpart. Moreover, this nanocatalyst showed regular behavior after five reuse cycles with a minimal loss in activity. This work thus shows that Mg doping effectively enhances ferrite catalytic efficiency through electronic modification and provides a viable route for fast C–C bond formation under mild, green conditions.