Covalently bonded sulfonic acid onto the surface of magnetic nanosilica obtained from rice husk: CoFe2O4 @RH-Pr-SO3H as novel acid catalyst for synthesis of octahydroquinazolinone and 3,4-dihydropyrimidinone

In this research project, an environmentally friendly solid catalyst was synthesized from low-cost rice husk (RH-SiO 2 ). Then, RH-SiO 2 was applied to support cobalt ferrite (CoFe 2 O 4 ) on the surface or inside the pores of amorphous SiO 2 . The nanoparticles were later modified by sulfonated (CoFe 2 O 4 @RHPr-SO 3 H) through modification with 3-mercaptopropyltrimethoxysilane (MPTMS) and subsequent oxidation with hydrogen peroxide (H 2 O 2 ). The characterization techniques including FT-IR, BET, CHNS, FE-SEM, TEM, VSM, TGA-DTG, EDX and X-ray mapping confirm the structure of this supported complex. Furthermore, the effect of the preparation method of the catalyst CoFe 2 O 4 @RH-Pr-SO 3 H was extensively studied against the synthesis of 3,4-dihydropyrimidinones and octahydroquinazolinones. There are no harmful organic solvents used in the current approach. The nontoxic nature, short reaction times, easy recovery and efficient reusability of the CoFe 2 O 4 @RH-Pr-SO 3 H are advantages of this approach. The nanocatalyst could be recovered easily and reused several times without the loss of its activity.(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

In this research project, an environmentally friendly solid catalyst was synthesized from low-cost rice husk and applied to support cobalt ferrite. The modified nanoparticles were characterized, and the effect of the catalyst preparation method was extensively studied against the synthesis of specific compounds. The nontoxic nature, short reaction times, easy recovery, and efficient reusability of the catalyst are advantages of this approach.