Magnetic Nanocatalyst Research Articles

Optimization of the microreactor-intensified transesterification process using silver titanium oxide nanoparticles decorated magnetic graphene oxide nanocatalyst

In the current study, the biodiesel fuel generation from waste cooking oil (WCO) as a low-cost feedstock was performed in a T-shaped microreactor through a transesterification process in the presence of binary metal oxide of silver-titanium oxide nanoparticles doped over magnetic graphene oxide (MGO@TiO2Ag) as a novel catalyst. Scanning electron microscopy (SEM), Transform Infrared Spectroscopy (FTIR), vibrating-sample magnetometer (VSM), Energy-Dispersive X-ray Spectroscopy (EDX), and Powder X-ray diffraction (XRD) were employed to characterize the MGO@TiO2Ag nanocatalyst. The Box-Behnken design (BBD) based on the response surface methodology (RSM) was used to optimize the reaction parameters, including methanol to oil volume ratio (Me/Oil), residence time and catalyst concentration. Following data analysis and optimization of the transesterification reaction, the maximum yield of fatty acid methyl esters (FAMEs) which was equal to 96.54 ± 1.16 %, was achieved at the residence time of 169.15 s, Me/Oil ratio of 2.52, and catalyst concentration of 4.15 wt%. All attributes of the manufactured FAMEs were within the permitted ranges of the ASTM D6751 standard, indicating high quality. The finding of this work demonstrated that employing a microreactor has an influential role in producing FAMEs in the presence of an MGO@TiO2Ag nanocatalyst.

Tri-vanadium Substituted Dawson-type Heteropolytungstate Nanocomposite (g-C3N4/Fe3O4@P2W15V3) as a Novel, Green, and Recyclable Nanomagnetic Catalyst in the Synthesis of Tetrahydrobenzo[b]Pyrans

Among the important needs of human societies are the reduction of biological pollution and the use of environmentally friendly and inexpensive solvents. For the synthesis of medicinally important heterocycles, there is a need for an easy, efficient, and environmentally friendly catalytic protocol through multicomponent reaction (MCR). In this regard, the construction of multi-functional composites has been considered. A novel magnetic graphite carbon nitride decorated by tri-vanadium substituted Dawson-type heteropolytungstate nanocomposite (C3N4/Fe3O4@P2W15V3) effectively synthesized and characterized by prevalent functional analysis. This heterogeneous catalyst produced various tetrahydrobenzo[b]pyran derivatives in the presence of ethanol as a green solvent. Among the advantages observed for this method is the presence of a heterogeneous and reusable catalyst that is easily isolated and provides a high yield of products in a very short reaction time with high purity.

Preparation and characterization of a magnetic catalyst for coupling reactions

Pd supported on 2-aminoquinoline-7-carboxylic acid functionalized Fe3O4 nanoparticles (Fe3O4-AQCA-Pd) as a new magnetic nanocatalyst was prepared and characterized by ICP-AES, FT-IR, XRD, SEM, TEM, TGA, XRD and EDX techniques. This nanocatalyst is employed for coupling reactions of pyridyl esters with phenylboronic acid to obtain ketone derivatives in good to excellent yields. This green catalyst was easily removed, reused several times with no significant loss of activity and provided a clean synthesis with excellent yield in reduced times.

An Efficient Procedure for the Synthesis of 2-Arylsubstituted Benzimidazoles Catalyzed by Co (II) Immobilized on Fe3O4@SiO2-NH2/EP@SAA as a Recyclable Nanomagnetic Catalyst

An Efficient Procedure for the Synthesis of 2-Arylsubstituted Benzimidazoles Catalyzed by Co (II) Immobilized on Fe3O4@SiO2-NH2/EP@SAA as a Recyclable Nanomagnetic Catalyst

Synthesis of new magnetic nanocatalyst Fe3O4@CPTMO-phenylalanine-Ni and its catalytic effect in the preparation of substituted pyrazoles

In this study, a new, efficient and stable magnetically heterogeneous nanocatalyst of Fe3O4@CPTMO-phenylalanine-Ni via multi steps process starting from simple and cost-effective precursors was designed and successfully synthesized, and physico-chemical, structural, and magnetic properties have fully been characterized by several analytical methods involving SEM–EDS, FT-IR, TGA, VSM, XRD, ICP, BET, TEM, and EMA. The catalytic performance of the Fe3O4@CPTMO-phenylalanine-Ni can be used as an effective and recyclable nanocatalyst with facile separation by magnetic forces for the preparation of substituted pyrazoles with high yields through the one-pot, three-component condensation reaction of various arylglyoxals, diketones, and 1H-pyrazole-5-amines under mild conditions. The nanocatalyst’s activity after being used by four consecutive times in a cycle reaction without distinct deterioration remained unchanged or was found to be a slight decrease. The advantages of this study are simplicity, low cost, facile synthesis process, and environmentally secure nature.

Synthesis and Application of Novel Nanomagnetic Catalyst Fe3O4@SiO2@Pr–Gu–Cr–COOH in the Green Multi-component Synthesis of 1-(Benzothiazolylamino)methyl-2-naphthol

Synthesis and Application of Novel Nanomagnetic Catalyst Fe3O4@SiO2@Pr–Gu–Cr–COOH in the Green Multi-component Synthesis of 1-(Benzothiazolylamino)methyl-2-naphthol

Cyano-2-oxopyridines: Green synthesis, cytotoxicity evaluation and molecular docking study

An efficient four-component and one-pot synthesis of 1,6-diamino-3,5-dicyano-2-oxopyridine compounds were investigated in the presence of three catalysts such as bulk and nanosheet graphitic carbon nitride and IS@SMNPs (piperazinium ionic salt attached on silica-coated magnetic nanoparticle) as recyclable heterogeneous catalysts. From the results, the magnetic nanocatalyst was the best among examined catalysts. The highest yield (85%) and the shortest reaction time (40 min) were obtained (for the four-component reaction between benzaldehyde, malononitrile, ethyl cyanoacetate and hydrazine hydrate) in the presence of 50 mg of‏ ‏IS@SMNPs at room temperature. Recycling of IS@SMNPs was tested, and after the fifth cycle, 80% yield was obtained. Good yields in a short time, simple recycling, and being environmentally friendly are advantages of the magnetic catalyst. MTT assay screened the cytotoxicity of 6a, 6b, 6e, and 6h derivatives against two carcinoma cell lines, such as HeLa and MCF-7 (estrogen receptor-dependent). 6h and 6b exhibited the most potent cytotoxicity, respectively, and 6b showed the lowest one against both cell lines. The interactions of selected derivatives and Genistein (an estrogen receptor inhibitor) in the active site of estrogen receptor-α were predicted using molecular docking. The docking results of synthetic compounds illustrated similar interactions to redocked Genistein in the active site, and compounds 6e and 6h had the highest binding affinity.

Magnetite Pd-loaded nitrogen-rich porous organic polymer as a catalyst for suzuki-miyaura coupling reaction

Fe3O4@SiO2@DETA-POP/Pd (FSTNPd) recyclable magnetic nanocatalyst was synthesized, fully characterized, and its application in Suzuki-Miyaura coupling reaction was investigated. Initially, the nitrogen-rich diethylenetriamine-based porous organic polymer (DETA-POP) with high surface area was synthesized using diethylenetriamine (DETA) and cyanuric acid through dioxane-organic solvent interface method. Then, magnetic iron (II, III) oxide nanoparticles (Fe3O4 NPs) were synthesized and supported by SiO2 and (3-chloropropyl)trimethoxysilane (CPTMS). Thereafter, Fe3O4@SiO2@CPTMS was processed by DETA porous organic polymer. Further loading with Pd afforded the Fe3O4@SiO2@DETA-POP/Pd magnetically recoverable heterogeneous catalyst. The catalyst showed astonishing performance in mild conditions for Suzuki–Miyaura coupling reaction in water/ethanol. The collected data represent excellent catalytic activity of this catalyst, good yields of the products, simple work-up procedure, and short reaction times.

Recovery of NiFe2O4 from wastewater containing nickel citrate complexes and its application to activate peroxymonosulfate

A treatment method for wastewater containing nickel citrate complexes was first proposed, which conformed to the strategy of “treating waste with waste”. Nickel was recovered from wastewater containing nickel citrate complexes using ferrate (VI) and the recovered product was converted to the magnetic nanocatalyst iron-nickel spinel NiFe2O4 (NFO) via calcination. Subsequently, NFO was used to activate peroxymonosulfate (PMS) to degrade the nickel citrate complexes in wastewater. The morphology and crystallinity of NFO are controlled by changing the calcination temperature of the precursor, which in turn affects the catalytic properties and magnetic properties of NFO. The characterization results show that the increase of the calcination temperature can positively affect the crystallization and magnetic properties of NFO. The morphology of NFO-900 after calcination at 900 °C was octahedral nanoparticles with a maximum saturation magnetization intensity of 47.43 emu·g−1. This implies that it can be easily magnetically recovered from the wastewater. Experiments on the degradation of nickel citrate complexes by the NFO/PMS system showed that NFO-900 had the best potential to activate PMS. Electron spin resonance and quenching experiments confirmed that the main reactive oxygen species of the system were SO4•-, 1O2, •O2-, and •OH. NFO-900 also exhibited good reusability and catalytic performance after five consecutive cycles. This study provides a green and promising technology for the treatment of wastewater containing nickel citrate complexes.

Fabrication of Copper(II)-coated Magnetic Core-shell Nanoparticles an Engineered Nano-magnetic Catalyst for the Synthesis of Pyrano Pyrazole and Pyrazole Derivatives

Pyrano[2,3-c]pyrazole and 5-amino-1H-Pyrazole-4-carbonitrile derivatives were used in the presence of new copper(II)-coated magnetic core-shell nanoparticles Fe3O4@SiO2@Si(OEt)(CH2)3@melamine@TC to synthesize an engineered nanomagnetic catalyst in a mild green environment. The synthesized nanocatalyst was well characterized using different techniques. Fe3O4@SiO2@Si(OEt)(CH2)3@melamine@TC@Cu(OAc)2 is an environmentally friendly procedure to synthesize some novel Pyrano[2,3-c]pyrazole and 5-amino -1H-Pyrazole-4-carbonitrile. Relevant products were produced in green conditions with high to excellent yields. Interestingly, the catalyst can be easily separated from the reaction medium by an external magnet and can subsequently be used for successive reaction cycles (at least four times) without a significant reduction in catalytic activity. Energy dispersive X-ray analysis (EDX) was taken from the recovery catalyst for further investigation. The results showed no significant change in the percentage of synthesized catalyst elements. In this study, reaction conditions, i.e. the effect of temperature and amount of catalyst, were optimized using a systematic approach, namely, the design of experiment (DoE). The structures of the synthesized Pyrano[2,3-c]pyrazole and 5-amino-1H-Pyrazole-4-carbonitrile compounds were confirmed by 1H NMR, 13C NMR, and FT-IR spectra.

Application of spinel Type NixZn1−xFe2O4 magnetic nanocatalysts for biodiesel production from neem seed oil: Catalytic performance evaluation and optimization

Application of spinel Type NixZn1−xFe2O4 magnetic nanocatalysts for biodiesel production from neem seed oil: Catalytic performance evaluation and optimization

Correction to: 15-Membered Macrocyclic Schiff-Base-Pd(0) Complex Immobilized on Fe3O4 MNPs: An Novel Nanomagnetic Catalyst for the One-Pot Three-Component C–H Chalcogenation of Azoles by S8 and Aryl Iodides

Correction to: 15-Membered Macrocyclic Schiff-Base-Pd(0) Complex Immobilized on Fe3O4 MNPs: An Novel Nanomagnetic Catalyst for the One-Pot Three-Component C–H Chalcogenation of Azoles by S8 and Aryl Iodides

An Efficient and Attractive Synthetic Protocol for Three-component Preparation of NH-1,2,3-Triazoles Using a Novel Magnetically Recoverable Copper Catalyst

Due to their magnetic separation and recycling characteristics, magnetic nanocatalysts are widely used in a wide variety of organic reactions. 1,2,3-Triazoles are heterocyclic compounds with broad applications in organic chemistry, including medicine, materials, and synthetic chemistry; a wide range of 1,2,3-triazoles exhibits many biological activities, including activity against fungal, viral, allergic, and microbial infections has been also reported in the literature. In this work, a magnetic Fe3O4@SiO2 nanocatalyst modified with pyridine-tetrazole ligand supported copper (II) acetate [MNPs-Py/Tet-Cu(OAc)2] was constructed and used to catalyze this one-pot three-component reaction of NH-1,2,3-triazoles. This nanocatalyst can act as an excellent catalyst for these three-component reactions. The [MNPs-Py/Tet-Cu(OAc)2] nanocatalyst, which demonstrated effective magnetization as 43 emu/g, can be easily separate from the reaction mixture and reused for 7 times while preserving their catalytic activity. Also the diameter of the nanoparticles is about 70–97 nm with spherical morphology.

Magnetic Cu/Co nanoparticles supported on nitrogen‐doped porous carbon derived from Cu/Co@aZIF: Investigation of catalytic activity and structural properties

By calcining copper‐doped amorphous zeolitic imidazolate framework (Cu/Co@aZIF), a novel magnetic nanoporous carbon composite (Cu/Co@NPC) material was produced, characterized by different spectroscopic techniques, and used for the first time as an efficient catalyst for the azide‐alkyne cycloaddition (AAC) reaction and the reduction reaction of nitrophenol (RRN) under air in water. With this catalyst, the AAC and RRN reactions were conducted in aqueous solutions, and good to excellent yields of related products were synthesized in a short reaction time. The potential of the magnetic Cu/Co@NPC nanocatalyst for targeting RRN and AAC reactions was uncovered by studying specific substrates for RRN and AAC reactions. The Cu/Co@NPC magnetic nanocatalyst is recyclable at least five times, with just a drop of 6% and 22% in catalytic efficiency in RRN and AAC, respectively.

Copper (II) Complex Immobilized on Magnetic Nanoparticles Functionalized with Imine/Thio Ligand (Fe3O4@SiO2-Imine/Thio-Cu(II)): A Novel, Efficient and Reusable Nanomagnetic Catalysts for the Synthesis of 2,4,6-Triaryl Pyridines

Herein we introduce a novel and reusable nanomagnetic copper catalyst (Fe3O4@SiO2-Imine/Thio-Cu(II)) constructed by immobilizing copper (II) complex on the surface of magnetic nanoparticles functionalized with Imine/Thio group. The structure of the as-constructed Fe3O4@SiO2-Imine/Thio-Cu(II) nanomaterial was well analyzed by a number of spectroscopic techniques including: FT-IR, SEM, TEM, EDX, XRD, VSM, AAS and ICP-OES. Experimental studies have well revealed that Fe3O4@SiO2-Imine/Thio-Cu(II) nanomaterial is an ecofriendly and efficient nanocatalyst for synthesis of 2,4,6-triaryl pyridines (82%–98%) via a C-N bond cleavage of benzylamines under aerobic oxidations in PEG at 120 °C. The grafting of the copper catalyst to the surface of magnetic nanoparticles has increased the catalytic activity of the material and also simplified catalyst recovery from the reaction mixture by an external magnet. The Fe3O4@SiO2-Imine/Thio-Cu(II) nanocatalyst was readily recovered by simple magnetic decantation and can be reused seven cycles without considerable loss in catalytic activity.

Ultrasound Probe‐assisted Telescopic One‐pot Synthesis of Spiro[indene‐2,2’‐naphthalene]‐4’‐carbonitrile Derivatives using Fe3O4@SCH2CO2H@Ni‐NH2as a Reusable Nanocatalyst

AbstractIn this paper, a novel inorganic‐organic hybrid catalyst based on Fe3O4has been successfully developed during four simple steps. After construction of Fe3O4@SCH2CO2H, the presence of nickel and urea converts this catalyst into the porous nano magnetic catalyst. The prepared nanocatalyst was identified by FT‐IR, VSM, XRD, FE‐SEM, EDX, elemental mapping, TGA, TEM, and BET. Then, we have employed the prepared catalyst as a recoverable heterogeneous and nanoporous catalyst for synthesis of spiro[indene‐2,2’‐naphthalene]‐4’‐ carbonitrile derivatives via one‐pot telescopic four component reaction of malononitrile, cyclohexanone, aromatic aldehydes, and 1,3‐indandione under ultrasonic irradiation. As anticipated, prepared catalyst displayed significant performance in the promoting of the studied reaction. Eco‐friendly, facile workup, medium to excellent yields in short reaction times, broad range of products, high catalytic performance and reusability of the catalyst are some of the noticeable advantages of this protocol. Further, we can separate and reuse the catalyst six times without any significant loss of activity.

The synthesis of Fe3O4@SiO2@Pr‐N (CH2CH2OH)3 and Fe3O4@SiO2@Pr‐N (CH2CH2‐ OBuSO3H)3 as nanomagnetic catalysts and their application in the synthesis of tetrahydroacenaphtho[1,2‐b]indolones and docking studies

The Fe3O4@SiO2@Pr‐N (CH2CH2‐OBuSO3H)3 as magnetic nanocatalyst with Fe3O4 core has been synthesized and used in the synthesis of tetrahydroacenaphtho[1,2‐b]indolones, which was accomplished through the one‐pot four‐component reaction of 5,5‐dimethyl cyclohexane‐1,3‐dione, acenaphthoquinone, arylamines, and active methylenes under solvent‐free conditions at 80°C. Fe3O4@SiO2@Pr‐N (CH2CH2‐OBuSO3H)3 with high magnetical and nontoxic properties has a core‐shell structure. The molecular docking was performed against the cancer target like the crystal structure of the motor protein kinesin spindle protein in complex with adenosine‐5'‐diphosphate and monastrol (pdb: 1Q0B) (2) and crystal structure of Mcl‐1 in complex with compound 7‐(4‐carboxyphenyl)‐3‐[3‐(naphthalen‐1‐yloxy)propyl]pyrazolo[1,5‐a]pyridine‐2‐carboxylic acid (pdb: 3WIX) (3).

Synthesis of novel benzopyrimido[4,5-d]azoninone analogs catalyzed by biosynthesized Ag-TiO2 core/shell magnetic nanocatalyst and assessment of their antioxidant activity.

The present work reported the synthesis of novel benzopyrimido[4,5-d]azoninone analogs using a biosynthesized Ag-TiO2 core/shell magnetic nanocatalyst. Accordingly, three-component one-pot reactions of benzoazonine-dione with thiourea and aryl aldehyde derivatives under nanocatalytic and optimized conditions afforded reasonable to brilliant yields of the target products (57-91%). The nanocatalyst was synthesized by a facile method using turmeric ethanol extract as a reducing and chelating agent. The synthesized nanocatalyst was verified by FT-IR, XRD, zeta potential, EDX, SEM, and TEM. The nanocatalyst presented remarkable catalytic activity for the synthesis of the target products. The procedure provided biosynthesis of the nanocatalyst, accessible reagents, high yields and rates of the reactions, nanocatalyst recyclability, and ease of product isolation and purification. The novel products were characterized by FT-IR, 1H-NMR, 13C-NMR, mass spectra, and 2D NMR analysis (COSY, NOESY, HMQC & HSQC) spectral analyses. The antioxidant activity was assessed by DPPH and phosphomolybdate assays, in which the compounds exhibited excellent potency. Overall, this approach could be used to develop new and sustainable methods for the synthesis of antioxidants and other biologically active molecules.

Synthesis of pentasubstituted pyrroles in improved emulsion medium using an efficient cosurfactant-modified magnetic nanocatalyst

In this study, a novel and environmental strategy is reported for multicomponent synthesis of pyrrole derivatives in water. We prepare and characterize Fe3O4@CTAB-SDS@Cu2+-Ag+ as a double surfactant-modified magnetic nanocatalyst. We compare catalytic activity of this catalyst with a mono surfactant-modified catalyst in the synthesis of pyrroles. It seems that the addition of Sodium dodecyl sulfate (SDS) as cosurfactant provides better stabilization of the emulsion and leads to the production of adhesive emulsions by the formation of a bilayer. On the other hand, surface decoration of SDS by Cu2+ and Ag+ improves catalytic activity. The magnetic nanocomposite was characterized by TEM, EDS, XRD, VSM and FT-IR techniques and the structure of the synthesized pyrrole was confirmed by FT-IR, 1H NMR and 13C NMR.

Research on the catalytic activity of MNP-[Dop-OH]-CuBr2 nanocomposites: novel and stable reusable nanocatalysts for the synthesis of 1,3,5-triazine derivatives.

In recent years, magnetic nanocatalysts have been recommended as one of the best catalysts by chemists. Among magnetic nanoparticles, Fe3O4 nanoparticles are highly suitable due to their magnetic properties, chemical stability and low toxicity. These catalysts can be separated via magnetic separation after the chemical process is over and reused after regeneration. Owing to the importance of 1,3,5-triazine derivatives in pharmaceutical and medicinal chemistry, the synthesis of these compounds is always one of the important goals of organic chemists. In this research work, we first successfully synthesized CuBr2 immobilized on magnetic Fe3O4 nanoparticles functionalized with Dop-OH (prepared via the reaction of MNP-dopamine with 2-phenyloxirane) nanocomposites and then investigated their catalytic application in the synthesis of 1,3,5-triazine derivatives via an oxidative coupling reaction of amidine hydrochlorides and alcohols in air. Recycling experiments clearly revealed that MNP-[Dop-OH]-CuBr2 nanocatalysts could be reused for at least 8 times without much loss of catalytic activity.