A facile method for synthesis of amine-functionalized mesoporous zirconia and its catalytic evaluation in Knoevenagel condensation

Amine-functionalized mesoporous zirconia was prepared by a co-condensation method using silane (aminopropyltrimethoxysilane, APTES) and zirconium butoxide. The materials were characterized by X-ray diffraction, BET surface area analysis, 13C magic angle spinning-nuclear magnetic resonance (NMR), Fourier-transfer infrared spectroscopy (FTIR), transmittance electron micrography (TEM), and CHN analysis. FTIR and NMR results revealed the successful grafting of organic amines onto the surface of zirconia. The catalytic activities were investigated for liquid phase Knoevenagel condensation of various aromatic aldehydes with diethyl malonate. The catalysts showed excellent yield of products at room temperature in solvent-free condition.

In the Knoevenagel condensation reactions, the catalyst activity is mainly due to the structural basicity of the amine group. The reaction is initiated when a benzaldehyde molecule reacts with a surface amine to form an amine compound. The addition of diethyl malonate and the subsequent molecular rearrangement produces the final reaction product and water molecules.Figure optionsDownload high-quality image (29 K)Download as PowerPoint slide