A facile, environmentally-benign, green and a novel synthesis of tert-butyl-quinolines by using Fe3O4-MWCNT@CeO2 as recyclable catalyst
Adapaka Venkateswara Rao, Suresh Maddila, Sai Sonali Anantha, Pamerla Muralidhar, Podilapu Atchutha Rao, Harihara Padhy, Sreekantha B. Jonnalagadda
Abstract
The aim of the present work is to examine the catalytic activity of ceria (CeO 2 ) supported on a nano-composite of iron oxide and multi-walled carbon nanotubes (Fe 3 O 4 -MWCNT). A simple impregnation protocol was used to synthesize Fe 3 O 4 -MWCNT@CeO 2 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 CeO 2 supported on Fe 3 O 4 -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 NH 4 OAc was used to evaluate the catalytic performance of the Fe 3 O 4 -MWCNT@CeO 2 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.