Synthesis, characterization and application of sulfonic acid supported on ferrite–silica superparamagnetic nanoparticles

Abstract

aIn this study, the synthesis of sulfonic acid supported on ferrite-silica superparamagnetic nanoparticles (Fe 3 O 4 @SiO 2 @SO 3 H) as a nanocatalyst with large density of acidic groups is suggested. This nanocatalyst was prepared in three steps: preparation of colloidal iron oxide magnetic nanoparticles (Fe 3 O 4 MNPs), coating of silica on Fe 3 O 4 MNPs (Fe 3 O 4 @SiO 2 ) and incorporation of sulfonic acid as a functional group on the surface of Fe 3 O 4 @SiO 2 nanoparticles (Fe 3 O 4 @SiO 2 @SO 3 H). The properties of the prepared magnetic nanoparticles were characterized using transmission electron microscopy, infrared spectroscopy, vibrating sample magnetometry, X-ray diffraction and thermogravimetric analysis. Finally, the applicability of the synthesized magnetic nanoparticles was tested as a heterogeneous solid acid nanocatalyst for one-pot synthesis of diindolyloxindole derivatives in aqueous medium. Oxindole derivatives were produced by the coupling of indole and isatin compounds with good to high yields (60-98%).

Recent applications of isatin in the synthesis of organic compounds

“…51 Crystal structure of the product was determined by X-ray structure analysis. In other studies, the reactions of various isatin derivatives 1 and indoles 57 were also investigated in the presence of nano SiO2 52 and Fe3O4@SiO2@SO3H 53 as catalysts.…”

Fe3O4@SiO2–ZrCl2‐MNPs: A novel magnetic catalyst for the clean and efficient cascade synthesis of 1‐(benzothiazolylamino)methyl‐2‐naphthol derivatives in the absence of solvent

“…Then the resultant mixture was heated in a water bath for 4 h at 80°C. The black solid MNPs were isolated using an external magnet and washed with deionized water and ethanol three times and then dried at 80°C for 10 h. [21] 2.2.2 | Preparation of Fe 3 O 4 @SiO 2 magnetic nanoparticles 300 mg Fe 3 O 4 -MNPs were dispersed in a mixture of 40 ml of EtOH and 4 ml of deionized water by ultrasonication for 15 min, followed by the addition of 5 ml of NH 3 .H 2 O (28 wt.%) and 2 ml of tetraethylorthosilicate (TEOS). The mixture was stirred at 400 rpm for 12 h at room temperature.…”

Magnetic solid sulfonic acid-enabled direct catalytic production of biomass-derived N-substituted pyrroles

“…31 Fe 3 O 4 nanomaterials have great development potential in overcoming the cumbersome catalyst separation process from the system due to their magnetic properties and the economy of raw materials. 32 To overcome the shortcomings of the above catalytic system, a new type of magnetic carbon-based sulfonic acid material was designed and prepared in this paper, and it was successfully applied to catalyze the synthesis of a series of N-substituted pyrrole derivatives from biomass-based 2,5-dimethylfuran and amine compounds via a one-pot multi-step reaction. In particular, the catalytic reaction system showed the characteristics of easy separation and recovery, green synthesis process, and sustainability.…”