RESUMEN
A straightforward, expeditious, robust, and efficient synthesis of NiO@Bentonite nanocatalyst was done using a simple microwave method. The X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX), Brunauer-Emmett-Teller (BET), thermal behavior analysis, and vibrating sample magnetometer (VSM) techniques were used to characterize the physicochemical properties of the NiO@Bentonite nanocomposites. The outcomes demonstrated that the NiO nanoparticles are evenly distributed throughout the Bentonite surface and that the NiO@Bentonite nanocomposites have a high specific surface area and rich pore structure. The following report details the investigation of this catalyst for the preparation of 1, 8-dioxodecahydroacridine heterocycles in a one-pot, three-component reaction of aromatic aldehydes, dimedone, and aniline. After the conditions were optimized, the results demonstrated that this reaction could be carried out in an aqueous medium with a good yield.
RESUMEN
In this research, a suitable and efficient CoFe2O4@ZnO@Bentonite nano-catalyst was designed and synthesized by using zinc oxide (ZnO) and cobalt ferrite (CoFe2O4) nanoparticles and bentonite by microwave irradiation. Characteristics of the synthesized nanocomposite were investigated by Fourier transform infrared (FT-IR), scanning electron microscope (SEM), energy dispersive X-ray (EDX), transmission electron microscope (TEM), X-ray diffraction (XRD), Bruner- Emmett-Teller (BET) and vibrating sample magnetometer (VSM) techniques. The produced catalyst was effectively employed as a supported solid acid catalyst in mildly agitated three-component reactions involving aromatic aldehydes, 4-hydroxycoumarin, and 1,3-dimethyl-barbituric acid in a single pot to produce benzylbarbiturocoumarins. Starting materials were condensed via three C-C bond formation by CoFe2O4@ZnO@Bentonite as an efficient, recyclable, and environmentally safe nanocatalyst to obtain target products. The advantages of this method include using a natural substrate, small amounts of catalyst, aqueous media, performing reactions at ambient temperature, simple separation and purification of products, and good yields with short reaction times.
RESUMEN
In this study, a Co-MOF was synthesized via a co-precipitation procedure and then used as support for stabilizing Ag ions and producing Co-MOF@Ag2O nanocomposite by microwave irradiation. The characterization of synthesized Co-MOF@Ag2O nanocomposite was performed by using different techniques such as field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX) analyses, X-ray diffraction (XRD), Thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET) and Fourier-transform infrared (FT-IR). The prepared Co-MOF@Ag2O nanocomposite was applied as a heterogeneous nano-catalyst in the synthesis of pyrazolopyranopyrimidines in water at 50 °C via the one-pot multicomponent reaction of ethyl acetoacetate, hydrazine hydrate, aromatic aldehydes and barbituric acid derivatives. Through this straightforward and effective protocol, different tricyclic fused pyrazolopyranopyrimidines were synthesized at high yields, and short reaction times, through an uncomplicated work-up process with no by-product. The Co-MOF@Ag2O nanocomposite has been effectively recycled for four consecutive cycles without appreciable loss in its activity. Cost-effectiveness, no need for column chromatography, mild conditions, catalyst recyclability, and eco-friendly nature make it a promising candidate compared to other methods.
RESUMEN
In this study, a new and efficient Rod-like bifunctional Fe-based MOF@CuO nanocomposites (RL BF Fe-based MOF@CuO NC) were synthesized as new and efficient heterogeneous catalyst through a simple method from easily available 1,3,5-benzenetricarbocylic acid linker, nitrate ferric as a source of iron and copper oxide (CuO) nanoparticles under microwave irradiation. The synthesized nanocatalysts were characterized with different techniques such as Brunauer-Emmett-Teller (BET), energy dispersive spectroscopy (EDS), field emission scanning electron microscopy (FE-SEM), mapping, transmission electron microscopy (TEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FT-IR). The RL BF Fe-based MOF@CuO NC had relatively high specific surface area (203 m2 g-1) while exhibiting superparamagnetic properties. The catalytic activity of RL BF Fe-based MOF@CuO NC was explored in a facile and green methodology to prepare diverse Namino-2-pyridones by one-pot four component reactions comprising aromatic aldehyde, malononitrile, methyl cyanoacetate and hydrazine hydrate within mild and solvent-free conditions. This protocol enjoys features like providing the final products during low reaction times in excellent yields under solvent-free conditions. The use of easily available and inexpensive reactants for the synthesis of the catalyst, environmental compatibility, low catalyst loading, fast and clean work-up and reusability of catalyst for several cycles with consistent activity are counted as the outstanding features of this procedure.
RESUMEN
Various pyrano[2,3-d]pyrimidines were synthesized by the multicomponent reaction of aldehydes, malononitrile, and acidic C-H compounds such as barbituric acid through the tandem Knoevenagel-Michael cyclocondensation pathway in an environmentally friendly reactive medium in the presence of a recoverable nanocomposite. This nanocomposite includes Fe3O4 nanoparticles placed on an organometallic framework. The synthesized Fe3O4@iron-based metal-organic framework nanocomposite was characterized using scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray powder diffraction, a vibrating sample magnetometer, and thermogravimetric analysis.
RESUMEN
In this study, controllable and optimal microwave irradiation has been used to synthesize the novel nanostructures of Bi2O3 under environmental conditions. The final products had a thermal stability of 210°C, an average particle size distribution of 85 nm, and a surface area of 783 m2/g. The high thermodynamic stability of Bi2O3 nanostructures was confirmed by TG and differential scanning calorimetry (DSC) analyses. The nanostructure nature of compounds, and most importantly, the use of an effective, cost-effective, and rapid synthesis route of microwave have created significant physiochemical properties in the Bi2O3 products. These unexpected properties have made the possibility of potential application of these products in various fields, especially in nano-catalyst applications. It is well-documented that, as Lewis acid, bismuth nano-catalyst exhibits a great catalytic activity for the green synthesis of some bio-active barbituric acid derivatives using precursors with electron-donating or electron-withdrawing nature in high yields (80%-98%). After incorporating this catalyst into the aqueous media, all the reactions were completed within 2-3 min at room temperature. The main advantages of this method are practical facility, the availability of starting materials, and low costs besides the catalyst reusability. Additionally, the catalyst synthesis process may be carried out in the aqueous media for a short period with medium to high yields. The obtained results have opened a new window for the development of a novel nano-catalyst with practical application.
RESUMEN
In this study, the recyclable heterogeneous cluster bud Fe-MOF@Fe3O4 'nanoflower' composite (CB Fe-MOF@Fe3O4 NFC) was successfully synthesized using Fe(NO3)3·9H2O, 8-hydroxyquinoline sulfate monohydrate, and Fe3O4 nanoparticles by microwave irradiation. The as-prepared CB Fe-MOF@Fe3O4 NFC was characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), vibrational sampling magnetometry (VSM), and Fourier transform infrared spectroscopy (FTIR). The CB Fe-MOF@Fe3O4 NFC samples proved to have excellent catalytic activity. The activity of the CB Fe-MOF@Fe3O4 NFC nanocatalyst was explored in the synthesis of dihydropyrano[3, 2-c]chromene derivatives via a three-component reaction of 4-hydroxycoumarin, malononitrile, and a wide range of aromatic aldehyde compounds. Optimized reaction conditions had several advantages, including the use of water as a green solvent, environmental compatibility, simple work-up, reusability of the catalyst, low catalyst loading, faster reaction time, and higher yields.