Recyclable Heterogeneous Nanocatalyst Research Articles

A new Schiff-base complex of palladium nanoparticles on modified Fe3O4 with 3,5-diaminobenzoic acid (DAA) as a robust, reusable, and selective catalyst in the C[sbnd]N and C[sbnd]C coupling reactions

A Pd Schiff base complex was immobilized onto the surface of magnetic Fe3O4 as a novel, green, and recyclable heterogeneous nanocatalyst and fully characterized by TEM, XRD, FT-IR, BET, SEM, ICP-OES, EDS, TGA, and VSM techniques. The Fe3O4@SiO2@DAA@Schiff base-Pd(0) catalyst exhibits outstanding performance in catalyzing Buchwald-Hartwig and Stille coupling reactions, resulting in high yields of the corresponding products. This catalyst offers numerous benefits, such as a straightforward testing procedure, environmentally friendly reaction conditions, absence of hazardous solvents, quick reaction time, low catalyst usage, and the ability to be reused. Furthermore, the nanocatalyst could be effortlessly separated from the reaction mixture using a bar magnet, enabling its repeated recovery and reuse without compromising its stability or activity.

Magnetic curcumin–copper graphene oxide as facile and recyclable heterogeneous nanocatalyst for preparation of polyhydroquinolines and sulfoxides

In this research project, a versatile procedure has been designed for the preparation of supported copper@curcumin on magnetic graphene oxide nanoparticles (GO@Fe3O4@Cur–Cu). The structure of prepared nanocatalyst was characterized by several techniques including; Fourier transform infrared, powder X-ray diffraction, thermal gravimetric analysis, energy dispersive X-ray analysis, inductively coupled plasma optical emission spectroscopy, vibrating sample magnetometer, transmission electron microscopy, and scanning electron microscopy analyses. The catalytic properties of GO@Fe3O4@Cur–Cu were examined for the efficient synthesis of polyhydroquinolines as well as the preparation of sulfoxides through selective oxidation of sulfides in the presence of hydrogen peroxide.

The immobilization of L-Valine on superparamagnetic Fe3O4 nanoparticles as a novel, recoverable and green nanocatalyst for the synthesis of new thiazole derivatives

The novel immobilization of L-Valine on superparamagnetic Fe3O4 nanoparticles was prepared using a simple protocol for the first time. This compound acts as a highly efficient and recyclable heterogeneous nanocatalyst for the synthesis of thiazole derivatives via a one-pot and multi-component condensation reaction of arylglyoxals monohydrate, cyclic 1,3-dicarbonyls, and thiobenzamides in a water solvent. The structure of the nanocatalyst was characterized and confirmed using various techniques, such as Fourier transform infrared spectroscopy (FT-IR), Energy Dispersive X-ray (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TG/DTA), and vibrating sample magnetometry (VSM). This heterogeneous nanocatalyst can be easily recovered from the reaction mixture by an external magnetic field and reused for subsequent reactions at least five times without losing significant catalytic activity.

Palladium Nanoparticles Decorated over Polydopamine-coated Zn–Al-layered Double Hydroxide (Zn-Al LDH@PDA/Pd NPs) as Recyclable Heterogeneous Nanocatalyst for Suzuki–Miyaura Coupling Reactions

Palladium Nanoparticles Decorated over Polydopamine-coated Zn–Al-layered Double Hydroxide (Zn-Al LDH@PDA/Pd NPs) as Recyclable Heterogeneous Nanocatalyst for Suzuki–Miyaura Coupling Reactions

Polydopamine-modified Zn–Al-layered double hydroxide supported silver nanoparticles as recyclable heterogeneous nanocatalyst for reduction of 4-nitrophenol

This article introduces the design and synthesis of Ag NP garlanded polydopamine (PDA)-functionalized Zn–Al-layered double hydroxide (Zn-Al LDH@PDA) as a hybrid green nanocomposite material, hitherto unreported. The precursor Zn-Al LDH@PDA acted as a suitable shelter and stabilizing support for the in situ generated Ag NPs. The electron rich amino functions over the PDA facilitated the toxic reagent free green reduction of Ag ions in situ. A diverse range of advanced methods, including Fourier Transform Infrared Spectroscopy (FT-IR), Field Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive X-ray Spectroscopy (EDX), elemental mapping, Transmission Electron Microscopy (TEM), High Resolution Transmission Electron Microscopy (HR-TEM), Fast Fourier Transform (FFT), Inductively Coupled Plasma (ICP), N2 adsorption–desorption, and X-ray Diffraction (XRD) were employed to analyze the physicochemical features of the Zn-Al LDH@PDA/Ag nanomaterial. Catalytic performance of the Zn-Al LDH@PDA/Ag nanocomposite was subsequently appraised in the reduction of 4-nitrophenol (4-NP). The reactions were evaluated through time dependent UV–Vis spectroscopic study which proved the excellent potential of the catalyst. The Zn-Al LDH@PDA/Ag NPs nanocatalyst was isolated by centrifuge and stable enough to be reused for 8 consecutive times without considerable loss in activity.

A Novel Recyclable Magnetic Nano-Catalyst for Fenton-Photodegradation of Methyl Orange and Imidazole Derivatives Catalytic Synthesis.

A magnetite chlorodeoxycellulose/ferroferric oxide (CDC@Fe3O4) heterogeneous photocatalyst was synthesised via treated and modified cotton in two steps. The designed nanocomposites were characterised by FTIR, TGA, XRD, SEM, and VSM analyses. The Fenton-photocatalytic decomposition efficiency of the synthesised magnetic catalyst was evaluated under visible sunlight using Methyl Orange (MO) as a model organic pollutant. The impacts of several degradation parameters, including the light source, catalyst load, irradiation temperature, oxidant dose, and pH of the dye aqueous solution and its corresponding concentration on the Fenton photodegradation performance, were methodically investigated. The (CDC@Fe3O4) heterogeneous catalyst showed a remarkable MO removal rate of 97.9% at 10 min under visible-light irradiation. (CDC@Fe3O4) nanomaterials were also used in a heterogeneous catalytic optimised protocol for a multicomponent reaction procedure to obtain nine tetra-substituted imidazole derivatives. The green protocol afforded imidazole derivatives in 30 min with good yields (91-97%) at room temperature and under ultrasound irradiation. Generally, a synthesised recyclable heterogeneous nano-catalyst is a good example and is suitable for wastewater treatment and organic synthesis.

Cleaner Biofuel Production via Process Parametric Optimization of Nonedible Feedstock in a Membrane Reactor Using a Titania-Based Heterogeneous Nanocatalyst: An Aid to Sustainable Energy Development.

Membrane technology has been embraced as a feasible and suitable substitute for conventional time- and energy-intensive biodiesel synthesis processes. It is ecofriendly, easier to run and regulate, and requires less energy than conventional approaches, with excellent stability. Therefore, the present study involved the synthesis and application of a highly reactive and recyclable Titania-based heterogeneous nanocatalyst (TiO2) for biodiesel production from nonedible Azadhiracta indica seed oil via a membrane reactor, since Azadhiracta indica is easily and widely accessible and has a rich oil content (39% w/w). The high free fatty acids content (6.52 mg/g KOH) of the nonedible oil was decreased to less than 1% via two-step esterification. Following the esterification, transesterification was performed using a heterogeneous TiO2 nanocatalyst under optimum conditions, such as a 9:1 methanol-oil molar ratio, 90 °C reaction temperature, 2 wt.% catalyst loading, and an agitation rate of 600 rpm, and the biodiesel yield was optimized through response surface methodology (RSM). Azadhiracta indica seed oil contains 68.98% unsaturated (61.01% oleic acid, 8.97% linoleic acid) and 31.02% saturated fatty acids (15.91% palmitic acid, 15.11% stearic acid). These fatty acids transformed into respective methyl esters, with a total yield up to 95% achieved. The biodiesel was analyzed via advanced characterization techniques like gas chromatography-mass spectrometry (GC-MS), Fourier transform infrared spectroscopy (FT-IR), and nuclear magnetic resonance (NMR), whereas the catalyst was characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and Fourier transform infrared spectroscopy (FT-IR). Due to its physicochemical properties, Azadirachta indica seed oil is a highly recommended feedstock for biodiesel production. Moreover, it is concluded that the Titania-based heterogeneous nanocatalyst (TiO2) is effective for high-quality liquid fuel synthesis from nonedible Azadirachta indica seed oil in a membrane reactor, which could be an optional green route to cleaner production of bioenergy, eventually leading to sustenance, robustness, and resilience that will aid in developing a holistic framework for integrated waste management.

Application of Fe3O4/SiO2@ZnO magnetic composites as a recyclable heterogeneous nanocatalyst for biodiesel production from waste cooking oil: Response surface methodology

Fe3O4/SiO2@ZnO nanocomposite was synthesized using the co-precipitation method and then used as an efficient and reclaimable heterogeneous catalyst for biodiesel generation from waste cooking oil (WCO). The surface features of the nanocomposite were determined with XRD, FT-IR, Mapping, EDX, FESEM, BET, TEM, and VSM approaches. The specific surface area, mean particle size, and pore volume of Fe3O4/SiO2@ZnO were estimated to be 32.56 m2 g −1, 10.46 nm, and 0.15 cm3 g−1 respectively. The results of nanocatalyst characterization indicated that the distribution of Si and Zn elements in the lattice of Fe3O4 nanoparticles has been done successfully. The response surface methodology (RSM) and Box-Behnken design (BBD) were applied to design the experiment, statistical modeling, and optimization. The R2 value for RSM was found to be 0.9941, which indicates that the model is remarkably consistent with the experimental data. The maximum biodiesel yield for the synthesized nanocatalyst was achieved at 97.23% under optimum conditions, including methanol to oil molar ratio of 9.90:1, ultrasonic irradiation time of 30.13 min, and nanocatalyst dosage of 2.67 wt%. The stability assessment illustrated that the nanocatalyst can be efficiently reutilized for seven cycles (yield of 88.36%). Furthermore, it can be concluded that the Fe3O4/SiO2@ZnO nanocatalyst can be applied as an efficient and promising heterogeneous catalyst in biodiesel generation from WCO.

A Green Synthesis of Novel Derivatives of Thiazole-5-One Using Magnetic Supported Copper Nanocatalyst (γ-Fe2O3@HAp@CPTMS@AT@Cu(ӀI))

A highly efficient one-pot three-component protocol was devised for the synthesis of novel derivatives of ((phenylethlidene)hydrazinyl)thiazol-4(5H)one by the reaction of acetophenone derivatives, ethyl chloroacetate and thiosemicarbazide, in ethanol at room temperature in the presence of copper supported hydroxyapatite-encapsulated-γ-Fe2O3 (γ-Fe2O3@HAp@CPTMS@AT@Cu(ӀI)) as the new magnetically recyclable heterogeneous nanocatalyst. This novel protocol furnished the desired products in excellent yields (88–95%) and short reaction times (20–28 min). The structure and morphology of the synthesized catalyst were characterized by using various techniques such as FT-IR, Fe-SEM, EDX, XRD, TGA-DTA, and VSM.

A novel magnetic layered double hydroxide as potent mesoporous recyclable heterogeneous nanocatalyst for the synthesis of 1H‐chromeno[2,3‐b]pyridine‐3‐carbonitrile derivatives

A magnetically separable cobalt complex of macrocyclic pseudo‐crown ether (PCE) immobilized on magnetic Cu/Al‐layered double hydroxide (γ‐Fe2O3@Cu3Al‐layered double hydroxide (LDH)/PCE‐Co) was readily fabricated using a simple four‐step postsynthetic modification strategy. This newly prepared nanocomposite was characterized by different chemo‐physical approaches, including Fourier transform infrared (FT‐IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), inductively coupled plasma optical emission spectroscopy (ICP‐OES), vibrating sample magnetometer (VSM), X‐ray diffraction (XRD), nitrogen adsorption–desorption isotherms, energy‐dispersive X‐ray spectroscopy (EDX), and elemental mapping. The catalytic performance of these nanoparticles (NPs) was explored in the synthesis of diverse 1H‐chromeno[2,3‐b]pyridine‐3‐carbonitrile derivatives via one‐pot three‐component reactions under green reaction conditions. Environmentally benign reaction conditions, simple separation, high yields of the reactions, versatility, easy magnetic separation, and reusability for several runs without significant loss of catalytic performance are the key advantages that make this protocol an ideal alternative method for the synthesis of chromene derivatives.

A Facile Synthesis and Biological Screening of Pyrimidine Derivatives under Ultrasonic Irradiations by ZnCr2O4 Nano-Particles Catalyst

Using a recyclable catalyst, facile synthesis of pyrimidine derivatives (4a-e) is attributed through the one-pot multi-component reaction of 2-amino benzimidazole (1) substituted aromatic aldehydes (2a-e) with malononitrile (3) under ultrasonic irradiations. Synthesized derivatives might help society in getting more active pharmaceutical constituents. In this present work, series of substituted pyrimidine (4a-e) were synthesized and confirmed with different spectra characterization methods. The ZnCr2O4 nano-particles play a vital role in eco-friendly, highly efficient, recyclable heterogeneous nanocatalyst. Furthermore, synthesized pyrimidine derivatives showed significant biological activities. Advantages of this handy route are less reaction time, simple isolation, and highly yielded products.

Greener route for the removal of toxic heavy metals and synthesis of 14-aryl-14H dibenzo[a,j] xanthene using a novel and efficient Ag-Mg bimetallic MOF as a recyclable heterogeneous nanocatalyst

Removing of heavy metal ions from aqueous solutions has become a serious challenge from both biological and environmental viewpoints. Recently, metal-organic frameworks (MOF) including two metal ions in its framework have been enhanced as promising structure in the capture of various hazardous and toxic substances. Herein, Ag-Mg-MOF were synthesized through a one-step approach using solvothermal technique. Then, the as-synthesized Bimetallic MOFs were characterized by TEM, SEM, EDS, XRD, FTIR and N2 adsorption. The as-synthesized Ag-Mg-MOF samples were used for heavy metal removal. The results showed that the adsorption of cadmium, lead and Cupper ions on MOF was improved by the pH increasing. The experimental data were examined through Freundlich and Langmuir models. The fabricated Ag-Mg MOFs exhibit enhanced decontaminant performance toward Cu2+, Cd2+and Pb2 ions in terms of high adsorption capacities, Pb2+ (350 mg/g)> Cd2+ (270 mg/g)> Cu2+ (202 mg/g), and ultrafast kinetics compared to the monometallic Mg-MOF. FT-IR spectra of adsorbed pyridine methods and non-aqueous potentiometric titration were used for measuring surface acidity of the prepared MOF. It was observed that the surface acidity and the catalytic activity were increased in bimetallic MOF compared to monometallic MOF. The catalytic results of the formation of free solvent 14-aryl-14-Hdibenzo[a,j]xanthene compound by Ag-Mg MOF showed a high yield at a lower time. Also, the prepared MOF catalysts still preserved their initial catalytic activity even after the 4th run. The results of this work demonstrate that the novel Ag-Mg MOFs nanocatalysts have great potential for applications in environmental protection, especially in heavy metal ions removal present in wastewaters and in the synthesis of pharmacologically and biologically active compound.

Clean One-Pot Multicomponent Synthesis of Pyrans Using a Green and Magnetically Recyclable Heterogeneous Nanocatalyst

AbstractCopper ferrite (CuFe2O4) magnetic nanoparticles (MNPs) were synthesized via thermal decomposition and applied as a reusable and green catalyst in the synthesis of functionalized 4H-pyran derivatives using malononitrile, an aromatic aldehyde, and a β-ketoester in ethanol at room temperature. The nanoparticles were characterized by FT-IR, EDX, SEM, TGA, and DTG analysis. The catalyst was recovered from the reaction mixture by applying an external magnet and decanting the mixture. Recycled catalyst was reused for several times without significant loss in its activity. Running the one-pot three-component reaction at room temperature, using a green solvent under environmentally friendly reaction conditions, ease of catalyst recovery and recyclability, no need for column chromatography and good to excellent yields are advantages of this protocol.

Synthesis of 2-amino-3-cyano-4H-pyran derivatives using GO-Fc@Fe3O4 nanohybrid as a novel recyclable heterogeneous nanocatalyst and preparation of tacrine-naphthopyran hybrids as AChE inhibitors

Synthesis of 2-amino-3-cyano-4H-pyran derivatives using GO-Fc@Fe3O4 nanohybrid as a novel recyclable heterogeneous nanocatalyst and preparation of tacrine-naphthopyran hybrids as AChE inhibitors

Heterogenized magnetic graphene oxide‐supported N6‐Schiff base Cu (II) complex as an exclusive nanocatalyst for synthesis of new pyrido[2,3‐d]pyrimidine‐7‐carbonitrile derivatives

In this article, the synthesis of a novel and highly efficient recyclable and reusable heterogeneous nanocatalyst has been reported via the functionalizing of the Fe3O4‐magnetized graphene oxide nanosheets with the N6‐Schiff base Cu (II) complex (GO/Fe3O4@SPNC). The structure of this novel nanocatalyst was determined by different analytical techniques such as FTIR, FE‐SEM, TEM, TGA‐DTG, and VSM. The catalytic activity of the synthesized GO/Fe3O4@SPNC nanocatalyst was explored for the synthesis of several new 2H‐pyrido[3′,2′:6,7]pyrano[2,3‐d]pyrimidine‐7‐carbonitrile derivatives with excellent yields. All new derivatives were fully identified by various spectral (1H NMR, 13C NMR, FT‐IR, ESI‐MS) analyses. In addition, this nanocatalyst carried out satisfactory catalytic maintenance of activity and high chemical stability in the titled reactions after seven‐time of recycling without substantial loss of leaching.

MNPs–PhSO3H: A Sustainable, Recyclable and Eco-Friendly Catalyst Promoting the Green Synthesis of 3-Aminoisoxazolmethylnaphthols Under Solvent–Free Conditions

In this article, a one-pot three-component synthesis of 3-aminoisoxazolmethylnaphthol derivatives has been developed using Fe3O4–NHPhSO3H as a recyclable heterogeneous nanocatalyst using available 3-aminoisoazoles, aldehyde derivatives and 2-naphthol under solvent-free conditions. This environmentally friendly methodology with excellent green chemistry credentials, such as using the low loading of reusable, nontoxic, easy- to-handle catalyst, shorter reaction time without any byproduct, avoidance of hazardous organic solvents and easy workup (the catalyst can be easily separated from the reaction mixture by an external magnet), can be used in a wide range of applications. A one-pot three-component synthesis of 3-aminoisoxazolmethylnaphthol derivatives has been developed via Fe3O4–NHPhSO3H as a recyclable heterogeneous nanocatalyst by available 3-aminoisoazoles, aldehyde derivatives and 2-naphthol in solvent-free conditions. This green process with main aspects such as operational simplicity, good-to-excellent yields, low cost, easy handling, being eco-friendly and reusability of the catalyst, absence of any tedious workup or purification and avoidance of hazardous or toxic reagents/catalysts/solvents opens an effective and convenient way to naphthalen-2-ol-functionalized isoxazole systems, which are promising compounds for different biomedical applications.

Efficient and straightforward access to diverse and densely functionalized chromenes by 3-amino-1,2,4-triazole supported on hydroxyapatite-encapsulated- γ-Fe2O3 (γ-Fe2O3@HAp@CPTMS@AT) as a new magnetic basic nanocatalyst

A highly efficient and straightforward one-pot three-component synthesis of functionalized 2-amino-4H-chromenes and indole-substituted 3-amino-1H-benzo[f]chromenes have been developed by 3-amino-1,2,4-triazole supported on hydroxyapatite-encapsulated-γ-Fe2O3 (γ-Fe2O3@HAp@CPTMS@AT) as the new magnetically recyclable heterogeneous basic nanocatalyst. The wide range of valuable 4H-chromene and 1H-chromene structures having different substituents were efficiently synthesized using one-pot tandem Knoevenagel cyclocondensation reaction of aromatic aldehydes, active methylene nitriles (malononitrile and 3-cyanoacetylindole) and diverse phenolic nucleophiles (resorcinol, α-naphthol and β-naphthol) in the presence of nano γ-Fe2O3@HAp@CPTMS@AT in EtOH. The structure and morphology of the synthesized nanocatalyst were characterized by using various techniques such as FT-IR, FESEM, EDS, XRD, TGA-DTA and VSM. The catalytic activity of nano γ-Fe2O3@HAp@CPTMS@AT was evaluated and the results indicated its applicability as a novel, highly efficient, green, recyclable and promising heterogeneous basic nanocatalyst for the synthesis of 4H-chromene and 1H-chromene derivatives.

Synthesize of Folic acid functionalized dendritic fibrous nano-silica and its application as an efficient nanocatalyst for access to direct amidation of carboxylic acids with amines

A new nanomaterial based on folic acid functionalized dendritic fibrous nano-silica (FA-KCC-1-NH2) was synthesized and used as a recyclable solid acid and heterogeneous nanocatalyst towards efficient amidation of a variety of carboxylic acids with amines in toluene under reflux conditions. KCC-1 porous nanomaterials were produced utilizing a hydrothermal technique and in the next functionalized with folic acid moieties to yield KCC-1-NH-FA nanocatalyst. The structure of KCC-1, KCC-1-NH2 and KCC-1-NH-FA nanoparticles were investigated by FESEM, DLS, zeta potential and TEM, instrumental techniques. Also, the pore size of KCC-1-NH-FA nanoparticles were moreover investigated with BET where results revealed that the surface of this nanocomposite was expanded. The synthesized KCC-1-NH-FA nanoparticles showed effective catalytic activity in amidation of carboxylic acids with amines affording in high yields (76-89%) and short period of times. Moreover, other advantages of present method are easy workup, no need to use of chromatographic column and excellent recyclability of catalyst without significant loss in its catalytic activity which gives economic rewards.

Design and development of natural and biocompatible raffinose-Cu2O magnetic nanoparticles as a heterogeneous nanocatalyst for the selective oxidation of alcohols

Natural polymers are recently playing a vital role as a support for the noble metals. In the present study, raffinose from the classes of oligosaccharide polymer with a high capacity of magnetization was used as active support for the copper metal. The copper immobilized on the raffinose-based magnetic nanoparticles (MNPs) which can be used as a recyclable heterogeneous nanocatalyst for the selective oxidation of primary benzyl alcohols (PBA) to benzaldehyde (BAD) derivatives. The morphology and structure of the recoverable magnetic nanocatalyst were characterized using different microscopic and spectroscopic techniques including FT-IR, GC, VSM, XRD, TEM, TGA, FESEM and EDS analyses. Also, the optimum conditions of co-reactant, reaction time, oxidant, temperature and amount of the nanocatalyst for oxidation reaction were investigated. Moreover, the Fe3O4@raffinose-Cu2O NPs had a significant effect to enhance yield and reduce the reaction time.

1, 3, 5-Tris (2-hydroxyethyl) Isocyanurate Functionalized SBA-15 (THEIC-SBA-15): as a Novel Heterogeneous Nano-Catalyst for the One-Pot Three-Component Synthesis of Tetrahydrobenzo [b] Pyrans in Water

1, 3, 5-Tris (2-hydroxyethyl) isocyanurate functionalized SBA-15 is used as a novel, highly efficient, and recyclable heterogeneous nano-catalyst for the one-pot 3-component synthesis of tetrahydro benzo [b] pyran derivatives. These unique derivatives were synthesized through the condensation reactions of the enolizable compounds, different aldehydes, and malononitrile (or ethyl cyanoacetate) under the mild reaction conditions, in the short reaction times, and gives excellent yields in the refluxing H2O as a green solvent. The accuracy of synthesizing functionalized SBA-15 was confirmed with FT-IR spectroscopy. Then the catalyst was characterized by scanning electron microscopy (SEM), transition electron microscopy (TEM), and surface area analysis (BET). TEM images demonstrated that the synthesized catalyst had a hexagonal structure. Simplicity in the operation, rapidity, high yields, low cost, mild reaction conditions, catalyst with low loading, evading the usage of toxic change metals, stability, and the catalyst reusability are the main advantages of the proposed protocol.