Fe₃O₄-decorated MWCNTs as an efficient and sustainable heterogeneous nanocatalyst for the synthesis of polyfunctionalised pyridines in water

ABSTRACT

Fe₃O₄-multiwalled carbon nanotube (MWCNT) nanoparticles were prepared by using Astragalus membranaceus root extract and characterised by all parameters. The synthesised Fe₃O₄−MWCNTs were used as a heterogeneous catalyst for the synthesis of diverse polyfunctionalised pyridines. Pyridines are important heterocyclic compounds in many natural products and pharmaceuticals with a wide range of biological and medicinal properties such as quinine, papaverine, emetine. TEM images showed that the Fe₃O₄ nanoparticles coated on the outer surface of the MWCNTs were arranged in consistent patterns. The mean diameters of Fe₃O₄ nanoparticles and MWCNTs were ~15 and ~25 nm, respectively. X-ray diffraction (XRD) analysis and Raman spectroscopic techniques revealed the degree of graphitisation. After preparation of pyridines in water with excellent yields, the nanocatalysts were recovered by an external magnet without filtration and reused for several runs without any significant loss of their activity.

Graphical Abstract

KEYWORDS:

• Fe₃O₄−MWCNTs
• heterogeneous catalyst
• pyridines
• Astragalus membranaceus
• green synthesis

Acknowledgments

This work was supported by the [National Research Foundation of Korea #1] under Grant [2018R1A2B2004432]; [Priority Research Centers Program #2] under Grant [2014R1A6A1031189]; and [Nano Material Technology Development #3] under Grant [2012M3A7B4049675]

This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (2018R1A2B2004432) and the Priority Research Centers Program (2014R1A6A1031189). This research was supported by the Nano Material Technology Development Program of the Korean National Research Foundation (NRF) funded by the Korean Ministry of Education, Science, and Technology (2012M3A7B4049675).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Research Foundation of Korea grant funded by the Korean government (MSIT) [2018R1A2B2004432] and the Priority Research Centers Program [2014R1A6A1031189]. This research was supported by the Nano Material Technology Development Program of the Korean National Research Foundation (NRF) funded by the Korean Ministry of Education, Science, and Technology [2012M3A7B4049675].