Anchoring high density sulfonic acid based ionic liquid on the magnetic nano-magnetite (Fe3O4), application to the synthesis of hexahydroquinoline derivatives

Magnetic nano-Fe3O4 based on melamine was synthesized with surface high density functional group (6.6 mmol H+/g), namely SO3H, so that it is a novel Bronsted acid nano-magnetic supported ionic liquid catalyst, and acts as a solid heterogeneous catalyst. The prepared catalyst was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), vibrational sample magnetometry (VSM), and thermal gravimetric analysis (TGA). Catalyst activity was tested in the synthesis of hexahydroquinoline derivatives were by the four-component reaction of dimedone, aldehyde, ethyl acetoacetate, and ammonium acetate, with reduced reaction time. The proposed method has important features which include solvent free, mild, metal free, high yield, shorter reaction time, easy recovery of catalyst, and easy workup procedure. On the other hand, the design of experiment was used as a systematic method for programming of the reaction condition. Programming showed that the optimum reaction temperature and amount of catalyst were 65 degrees C and 0.04 g, respectively. (C) 2018 Published by Elsevier B.V.