Hollow Fe3O4@DA-SO3H: an efficient and reusable heterogeneous nano-magnetic acid catalyst for synthesis of dihydropyridine and dioxodecahydroacridine derivatives

A versatile magnetic nanocomposite based on cellulose-cyclodextrin hydrogel embedded with graphene oxide and Cu2O nanoparticles for catalytic application

The study focused on creating a novel and environmentally friendly nanocatalyst using cellulose (Cell), β-Cyclodextrin (BCD), graphene oxide (GO), Cu2O, and Fe3O4.The nanocatalyst was prepared by embedding GO and Cu2O into Cell-BCD hydrogel, followed by the in-situ preparation of Fe3O4 magnetic nanoparticles to magnetize the nanocomposite. The effectiveness of this nanocatalyst was evaluated in the one-pot, three-component symmetric Hantzsch reaction for synthesizing 1,4-dihydropyridine derivatives with high yield under mild conditions. This novel nanocatalyst has the potential for broad application in various organic transformations due to its effective catalytic activity, eco-friendly nature, and ease of recovery.

Facile route to synthesize Fe3O4@acacia-SO3H nanocomposite as a heterogeneous magnetic system for catalytic applications

In this work, a novel catalytic system for facilitating the organic multicomponent synthesis of 9-phenyl hexahydroacridine pharmaceutical derivatives is reported. Concisely, this catalyst was constructed from acacia gum (gum arabic) as a natural polymeric base, iron oxide magnetic nanoparticles (Fe3O4 NPs), and sulfone functional groups on the surface as the main active catalytic sites. Herein, a convenient preparation method for this nanoscale composite is introduced. Then, essential characterization methods such as various spectroscopic analyses and electron microscopy (EM) were performed on the fabricated nano-powder. The thermal stability and magnetic properties were also precisely monitored via thermogravimetric analysis (TGA) and vibrating-sample magnetometry (VSM) methods. Then, the performance of the presented catalytic system (Fe3O4@acacia-SO3H) was further investigated in the referred organic reaction by using various derivatives of the components involved in the reaction. Optimization, mechanistic studies, and reusability screening were carried out for this efficient catalyst as well. Overall, remarkable reaction yields (94%) were obtained for the various produced derivatives of 9-phenyl hexahydroacridine in the indicated optimal conditions.

Preparation and Application of Magnetic Nano-Solid Acid Catalyst Fe3O4-PDA-SO3H

A magnetic nano-solid acid catalyst Fe3O4-PDA-SO3H was synthetized through an efficient method, as an eco-friendly and more efficient catalyst. The obtained catalyst has uniform core-shell structure, appropriate particle size, and high acid density. Fe3O4-PDA-SO3H was applied to catalyze the esterification of levulinic acid (LA) with alcohols of different chain length to produce the levulinate esters. The catalytic effect was optimized from the aspects of catalyst dosage, reaction temperature, and acid-alcohol molar ratio. Furthermore, the response surface optimization method was used to obtain the optimal conditions. Verified under these conditions, the experimental results showed that the conversion rate of LA can reach 95.87%, which was much higher than common cationic exchange resin Amberlyst 36 and Amberlyst 46. Furthermore, the recovery and reuse of the Fe3O4-PDA-SO3H was demonstrated six times without obvious loss in the activity.