Synthesis and characterization of Piperidine-4-carboxylic acid functionalized Fe 3O 4 nanoparticles as a magnetic catalyst for Knoevenagel reaction

Piperidine-4-carboxylic acid (PPCA) functionalized Fe 3O 4 nanoparticles as a novel organic-inorganic hybrid heterogeneous catalyst was fabricated and characterized by XRD, FT-IR, TGA, TEM and VSM techniques. Composition was determined as Fe 3O 4, while particles were observed to have spherical morphology. Size estimations using X-ray line profile fitting (10 nm), TEM (11 nm) and magnetization fitting (9 nm) agree well, revealing nearly single crystalline character of Fe 3O 4 nanoparticles. Magnetization measurements reveal that PPCA functionalized Fe 3O 4 NPs have superparamagnetic features, namely immeasurable coercivity and absence of saturation. Small coercivity is established at low temperatures. The catalytic activity of Fe 3O 4-PPCA was probed through one-pot synthesis of nitro alkenes through Knoevenagel reaction in CH 2Cl 2 at room temperature. The heterogeneous catalyst showed very high conversion rates (97%) and could be recovered easily and reused many times without significant loss of its catalytic activity.