Superparamagnetic nanoparticle-supported imidazole (Im@MNPs) was prepared and used as magnetically
separable catalyst for Knoevenagel condensation of aromatic aldehydes with active methylene compounds.
3.0 mol% of Im@MNPs with water as solvent was investigated as the optimal catalytic system. The active methylene
compounds involved malononitrile, ethyl 2-cyanoacetate, 2-(1H-benzo[d]imidazol-2-yl)acetonitrile, 2-
(benzo[d]thiazol-2-yl)acetonitrile, 2-phenylacetonitrile, 2-(3-chlorophenyl)acetonitrile, 2-(1H-indol-3-
yl)acetonitrile. All reactions preceded smoothly affording target products in good to excellent yields (78-99%)
within minutes to hours. More importantly, the catalyst could be reused up to ten times with only a slight decrease in catalytic activity. A
plausible mechanism was proposed to rationalize the high catalytic activity of catalyst.