A facile, environmentally-benign, green and a novel synthesis of tert-butyl-quinolines by using Fe3O4-MWCNT@CeO2 as recyclable catalyst

Abstract

The aim of the present work is to examine the catalytic activity of ceria (CeO2) supported on a nano-composite of iron oxide and multi-walled carbon nanotubes (Fe3O4-MWCNT). A simple impregnation protocol was used to synthesize Fe3O4-MWCNT@CeO2 nano-composite, and a diversity of analytical techniques (including XRD, BET, TGA, SEM, TEM, and EDS) were used to thoroughly describe the catalyst material. The CeO2 supported on Fe3O4-MWCNT were found to be uniformly distributed throughout the nano-composite, irregular spherical in shape, and ranged in size from 5 to 15 nm, according to high-resolution TEM image. Afterwards, the synthesis of novel tert-butyl-quinoline analogues via a multi-component condensation comprising substituted aldehydes, dimedone, 3°-butylacetoacetate, and NH4OAc was used to evaluate the catalytic performance of the Fe3O4-MWCNT@CeO2 nano-composite. Their large specific surface area, porosity, unique exposed surfaces, and stability all contribute to their effectiveness. The catalyst's extremely active surfaces are highlighted by the notably high turn-over frequency. Thus, using ethanol as the green solvent, we suggest an effective and reusable catalytic approach that works at mild reaction condition with excellent product yields (90–97 %). This makes that nano-composite inexpensive, safe for the environment, and very atom-efficient. When compared to existing commercial approaches, our protocol is found to be more sustainable and efficient.