Polyethylene Glycol-(N-Methylimidazolium) Hydroxide-Grafted -Fe2O3@HAp: A Novel Nanomagnetic Recyclable Basic Phase-Transfer Catalyst for the Synthesis of Tetrahydrobenzopyran Derivatives in Aqueous Media

Polyethylene glycol-(N-methylimidazolium) hydroxide-grafted hydroxyapatite encapsulated -Fe2O3 nanoparticles, -Fe2O3@HAp@PEG(mim)OH, were prepared and characterized by FTIR, SEM, TEM, TGA, and EDAX. This nanocomposite was applied as a novel, green, nanomagnetic, and recyclable basic phase-transfer catalyst for the synthesis of tetrahydrobenzopyrans in high yields via the three-component reaction of aromatic aldehydes, malononitrile, and dimedone or 1,3-cyclohexanedione in aqueous media at ambient temperature.