Dysprosium (III) Supported on CoFe2O4 MNPs as a Heterogeneous Catalyst for the Selective Oxidation of Sulfides and Synthesis of Symmetrical Disulfides

Mesoporous magnetic supported Cu complex for one-pot synthesis of 5-substituted 1H-tetrazoles in green media and the oxidation of sulfides

We used the copper Phthalocyanine (Pc) on magnetic mesoporous silica nanoparticles. Therefore, several coordination sites became available which enhance chelating potency to load appropriate amounts of Gadolinium (Gd). This improves the catalytic activity in converting nitrile to tetrazole and selective oxidation of sulfides. Gadolinium (Gd) with incompletely occupied 4f and empty 5d orbitals can be used as the active component or as the promoter of the catalyst. Here, we outline the synthesis, characterization, and catalytic activity of a novel Gd(III) copper Phthalocyanine (Pc) coordination on the CoFe2O4/SBA-15 (CoFe2O4/SBA-15/CuPc@Gd). The prepared material was characterized using powder X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, elemental mapping, vibrating-sample magnetometer (VSM), Inductively coupled plasma atomic emission spectroscopy (ICP-AES), Fourier transform infrared spectroscopy, and nitrogen adsorption-desorption isotherm. The CoFe2O4/SBA-15/CuPc@Gd composite consists of a mesoporous structure with a surface area by BET and t-plot of 122.2 m2/g and 86.28 m2/g respectively, with a mean pore size of 5.37 nm, and pore volume of 0.164 cm3/g. The CoFe2O4/SBA-15/CuPc@Gd was successfully applied as a powerful catalyst for green synthesis of 5-substituted 1H-tetrazoles in water and selective oxidation of sulfides at room temperature. This catalyst was recovered and reused several times without a significant decrease in efficiency and stability. The catalyst could be fully recovered by an external magnetic field and showed good reusability.

Synthesis, modifications, and applications of iron-based nanoparticles

Magnetic nanoparticles (MNPs) are appealing materials as assistant to resolve environmental pollution issues and as recyclable catalysts for the oxidative degradation of resistant contaminants. Moreover, they can significantly influence the advancement of medical applications for imaging, diagnostics, medication administration, and biosensing. On the other hand, due to unique features, excellent biocompatibility, high curie temperatures and low cytotoxicity of the Iron-based nanoparticles, they have received increasing attention in recent years. Using an external magnetic field, in which the ferrite magnetic nanoparticles (FMNPs) in the reaction mixtures can be easily removed, make them more efficient approach than the conventional method for separating the catalyst particles by centrifugation or filtration. Ferrite magnetic nanoparticles (FMNPs) provide various advantages in food processing, environmental issues, pharmaceutical industry, sample preparation, wastewater management, water purification, illness therapy, identification of disease, tissue engineering, and biosensor creation for healthcare monitoring. Modification of FMNPs with the proper functional groups and surface modification techniques play a significant role in boosting their capability. Due to flexibility of FMNPs in functionalization and synthesis, it is possible to make customized FMNPs that can be utilized in variety of applications. This review focuses on synthesis, modifications, and applications of Iron-based nanoparticles.

Fe3O4@SiO2@SBA-3@CPTMS@Arg-Cu: preparation, characterization, and catalytic performance in the conversion of nitriles to amides and the synthesis of 5-substituted 1H-tetrazoles

A novel, efficient, and recyclable mesoporous Fe3O4@SiO2@SBA-3@CPTMS@Arg-Cu nanocatalyst was synthesized by grafting l-arginine (with the ability to coordinate with Cu) onto a mixed phase of a magnetic mesoporous SBA-3 support. The catalyst was characterized using several techniques, including Fourier-transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), vibrating sample magnetometry (VSM), X-ray diffraction (XRD) analysis, N2 adsorption-desorption analysis, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray (EDX) analysis, and atomic absorption spectroscopy (AAS). The resulting solid material possessed a surface area of 145 m2 g-1 and a total pore volume of 34 cm3 g-1. The prepared mesoporous material was studied as a practical, recyclable, and chemoselective catalyst in some organic functional group transformations such as the conversion of nitriles to amides and synthesis of 5-substituted 1H-tetrazoles. This novel magnetic nanocatalyst proved to be effective and provided the products in high to excellent yields under green solvent conditions. Meanwhile, the as-prepared Fe3O4@SiO2@SBA-3@CPTMS@Arg-Cu demonstrated excellent reusability and stability under reaction conditions, and its catalytic activity shown only a slight decrease after seven consecutive runs. Therefore, the as-synthesized magnetic Fe3O4@SiO2@SBA-3@CPTMS@Arg-Cu has broad prospects for practical applications, and offers various benefits such as simplicity, nontoxicity, low cost, simple work-up, and an environmentally benign nature.

Fe3O4@SiO2@CSH+VO3- as a novel recyclable heterogeneous catalyst with core-shell structure for oxidation of sulfides

Iron nanoparticles, with low toxicity and many active sites, are among the materials that not only reduce waste along with green chemistry but also increase the separation power and recover the catalyst from the reaction environment. In this study, first, the surface of iron nanoparticles was silanized, and in the next step, the complex of chitosan HCl.VO3 was placed on the surface of Fe3O4 (Fe3O4@SiO2@CSH+VO3-). This nanocatalyst is a novel, recoverable, and potent nanocatalyst with high selectivity for the oxidation of sulfides to sulfoxides. Various physicochemical techniques such as IR, XRD, TGA, SEM, EDX, mapping, TEM, and VSM were used to affirm the well synthesis of the catalyst. Oxidation of sulfides in the presence of hydrogen peroxide as a green oxidant and in ethanol was catalyzed by the Fe3O4@SiO2@CSH+VO3-. All sulfoxides were achieved with high efficiency and in a short time. The notable privileges of this method include facile and economic catalyst synthesis, proper catalyst durability, great performance, simple catalyst isolation, good recovery capability, at least up to 5 times without an index drop in catalytic power.

Copper-decorated core-shell structured ordered mesoporous containing cobalt ferrite nanoparticles as high-performance heterogeneous catalyst toward synthesis of tetrazole

The present work describes the synthesis of copper immobilization on CoFe2O4/MCM-41 as a catalyst, which is created by attaching copper and ligand (N-phenyl anthranilic acid (PA)) on the surface of CoFe2O4/MCM-41 (CoFe2O4/MCM-41/PA/Cu). The synthesized CoFe2O4/MCM-41 support and immobilized copper were identified by FTIR, TEM, VSM, SEM XRD, and nitrogen adsorption-desorption analysis. The results showed that MCM-41 silica was coated with magnetite nanoparticles and copper was successfully immobilized on this structure. The catalytic performance of synthesized catalyst was tested in the synthesis of tetrazole. It was shown that the solid catalyst exhibited a strong magnetic response and showed good catalytic activity in the synthesis of tetrazole. The catalytic test showed that copper supported on CoFe2O4/MCM-41 hybrid showed much better catalytic activity than copper supported on CoFe2O4, indicating that MCM-41 plays an important role in CoFe2O4/MCM-41 hybrid for the synthesis of tetrazole. Separation of the solid catalyst from the reaction mixture was easily performed by external magnetism without apparent mass loss. And the catalyst could be reused six times for the synthesis of heterogeneous tetrazole.

Treasuring industrial sulfur by-products: A review on add-value to reductive sulfide and sulfite for contaminant removal and hydrogen production

Reductive sulfur-containing by-products (S-BPs) released from industrial process mainly exist in the simple form of sulfide and sulfite. In this study, recent advances to remove and make full use of reductive S-BPs to achieve efficient contaminant removal and hydrogen production are critically reviewed. Sulfide, serves as both reductant and nucleophile, can form intermediates with the catalyst surface functional group through chemical interaction, efficiently promoting the catalytic reduction process to remove contaminants. Sulfite assisted catalytic process could be classified to the advanced reduction processes (ARPs) and advanced oxidation processes (AOPs), mainly depending on the presence of dissolved oxygen (DO) in the solution. During ARPs, sulfite could generate reductive active species including hydrated electron (e_aq^-), hydrogen radical (H·), and sulfite radical (SO₃^•-) under the irradiation of UV light, leading to the efficient reduction removal of a variety of contaminants. During AOPs, sulfite could first produce SO₃^•- under the action of the catalyst or energy, initiating a series of reactions to produce oxysulfur radicals. Various contaminants could be effectively removed under the role of these oxidizing active species. Sulfides and sulfites could also be removed along with promoting hydrogen production via photocatalytic and electrocatalytic processes. Besides, the present limitations and the prospects for future practical applications of the process with these S-BPs are proposed. Overall, this review gives a comprehensive summary and aims to provide new insights and thoughts in promoting contaminant removal and hydrogen production through taking full advantage of reductive S-BPs.

Synthesis of efficient cobalt-metal organic framework as reusable nanocatalyst in the synthesis of new 1,4-dihydropyridine derivatives with antioxidant activity

Efficient cobalt-metal organic framework (Co-MOF) was prepared via a controllable microwave-assisted reverse micelle synthesis route. The products were characterized by SEM image, N2 adsorption/desorption isotherm, FTIR spectrum, and TG analysis. Results showed that the products have small particle size distribution, homogenous morphology, significant surface area, and high thermal stability. The physicochemical properties of the final products were remarkable compared with other MOF samples. The newly synthesized nanostructures were used as recyclable catalysts in the synthesis of 1,4-dihydropyridine derivatives. After the confirmation of related structures, the antioxidant activity of derivatives based on the DPPH method was evaluated and the relationship between structures and antioxidant activity was observed. In addition to recyclability, the catalytic activity of Co-MOF studied in this research has remarkable effects on the synthesis of 1,4 dihydropyridine derivatives.