Lewis Acidic Ionic Liquid Immobilized on Graphene Oxide: Synthesis, Characterization, and Application in the Ultrasound‐Assisted Condensation Reactions

Abstract

Abstract The catalytic activity of a novel Lewis acidic Fe(III)/caffeine‐based ionic liquid immobilized on graphene oxide (Caff‐IL‐GO/Fe) was studied in three condensation reactions in water under sonication. This catalyst was characterized by Fourier‐transform infrared spectroscopy, proton nuclear magnetic resonance, thermal gravimetric analysis, energy‐dispersive X‐ray spectroscopy, field emission scanning electron microscopy, powder X‐ray diffraction, and atomic force microscopy. The performance of the synthesized Caff–IL–GO nanocatalyst was investigated in the one‐pot ultrasound‐assisted synthesis of substituted 4H‐pyrans, dihydropyrimidinones and benzimidazoles. The Caff‐IL‐GO/Fe nanocatalyst exhibited excellent activity and delivered corresponding products in high to excellent yields. Additionally, the reusability and stability of the Caff–IL–GO was also investigated. Our study indicated that the nanocatalyst could be reused up to 10 times without any significant loss of activity.