Cu─Mg─Al LDH: An Efficient Catalyst for Knoevenagel Condensation

Abstract

Knoevenagel condensation is widely used in industry to produce pharmaceuticals and fine chemicals. In the present study, the Knoevenagel condensation of benzaldehyde with ethyl cyanoacetate was investigated over a Cu─Mg─Al layered double hydroxide (LDH) catalyst. The catalyst was synthesized using the co-precipitation technique and characterized comprehensively by FT-IR, X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) surface area analyzer, and X-ray photoelectron spectroscopic (XPS) technique. Excellent catalytic activity (product yield = 95%) was observed at 80 °C in ethanol. The structural integrity of the Cu─Mg─Al LDH catalyst was retained after five cycles (product yield >90%). The versatility of the catalyst for the Knoevenagel condensation was investigated with a series of substituted aromatic aldehydes and active methylene compounds. Cu─Mg─Al LDH was found to be a viable alternative to conventional catalysts for Knoevenagel condensation.