Heterogeneous Nanocatalyst Research Articles

Fe3O4@SiO2@[Aminoglycol][Formate] as a new superparamagnetic nanocatalyst and [Aminoglycol][Formate] as a novel ionic liquid catalyst for preparation of new dimethyldihydropyrimido[4,5-b]quinolone derivatives.

Efficient synthesis of novel dimethyldihydropyrimido[4,5-b]quinolones via three-component condensation of barbituric acid, arylaldehydes, and 3,4-dimethylaniline catalyzed by Fe3O4@SiO2@[Aminoglycol][Formate] as a new superparamagnetic nanocatalyst and [Aminoglycol][Formate] as a novel ionic liquid catalyst was described. The new heterogeneous nanocatalyst was characterized by FE-SEM, XRD, FT-IR, TGA-DTG, and VSM techniques. The new ionic liquid was characterized by 13CNMR, 1HNMR, and FT-IR techniques. The present work has advantages, such as excellent yields, short reaction times, environmentally friendly protocol, easy separation, and purification of products. The catalysts kept its catalytic properties after even five recoverability and reusability.

Preparation of New Aminodimethyl(Methylsulfonyl)Dihydropyrido[2,3-d]Pyrimidinedione Derivatives in the Presence of Fe3O4@SiO2@[O-(CH2)2-NH2][CH3CO2H] as Novel Nanocatalyst

An efficient synthesis of new aminodimethyl(methylsulfonyl)dihydropyrido[2,3-d]pyrimidinedione derivatives via the three components reaction of 2-methanesulfonylacetonitrile, 1,3-dimethyl-6-amino-uracil, and aromatic aldehydes in the presence of [HO-(CH2)2-NH2][CH3CO2H] and Fe3O4@SiO2@[O-(CH2)2-NH2][CH3CO2H] as novel heterogeneous magnetic nanocatalyst was described. The Fe3O4@SiO2@[O-(CH2)2-NH2][CH3CO2H] as nanocatalyst can be easily separated from the reaction mixture by an external magnet, recycled, and reused several times without any significant decrease in catalytic activity. These methods showed several advantages, including high yields, easy operation, and environment-friendly protocols.

Comparative study of cerium-manganese ratios in the design of Ce-Mn-binuclear LDH-based Cu complex: a potent nanocatalyst for the green synthesis of spiro[acridine-9,3’-indole]triones

The Ce-Mn binuclear LDH was prepared at four different molar ratios of Ce to Mn (1:1, 1:2, 1:3, and 1:4), modified with both 3-chloropropyltrimethoxysilane (CPTMS) and N-amino-phthalimide (NAP), complexed with Cu(II), and characterized by the FT-IR, ICP, XPS, XRD, BET, UV/Vis, EDX, SEM, SEM-mapping, TEM, and TGA-DTA techniques. The ICP, XPS, BET, and UV-vis techniques showed that the 1:4 molar ratio of Ce to Mn is the best, therefore it was used as a heterogeneous nanocatalyst for the green synthesis of fourteen spiro[acridine-indole]triones from the three-component condensation reaction of isatin, aniline, and 1,3-diketone in mild reaction conditions. The advantages of this method include the absence of harmful organic solvents, easy separation of the catalyst and products, and rapid achievement of excellent yields. Furthermore, the activity of the catalyst was maintained even after four consecutive runs without a significant loss of activity.

Revolutionizing acridine synthesis: novel core-shell magnetic nanoparticles and Co-Zn zeolitic imidazolate framework with 1-aza-18-crown-6-ether-Ni catalysts

Nanoparticles have emerged as a critical catalyst substrate due to their exceptional features, such as catalytic efficiency, high stability, and easy recovery. In our research, we have developed an innovative and environmentally friendly magnetic mesoporous nanocatalyst. Using the co-precipitation method, we produced magnetic nanoparticles (Fe3O4) and coated them with Zeolitic imidazolate frameworks (ZIFs) to enhance their surface area and chemical stability. The resulting substrate was functionalized with 1-aza-18-crown-6-ether and nickel metal. Our prepared catalyst has been rigorously evaluated using advanced techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmet-Teller (BET), vibrating sample magnetometry (VSM), scanning electron microscopy and energy dispersive X-ray (SEM-EDS), inductively coupled plasma (ICP), elemental mapping analysis (EMA), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM). By synthesizing acridine derivatives, we have demonstrated the exceptional efficiency of our catalyst in organic compound synthesis. Through optimization, we have established the ideal parameters for catalytic processes, including catalyst amount, temperature, time, and ultrasonic use. Our catalyst has been proven to exhibit remarkable physical and chemical properties, such as porosity, temperature resistance, and recyclability. Notably, our heterogeneous nanocatalyst has shown outstanding performance and can be recycled six times without any loss in efficiency, affirming its potential in acridine.

Dendrimer templated ionic liquid nanomagnetic for efficient coupling reactions

In this research, a logical strategy with a recyclable synthetic perspective of view and a rational design to prepare a nanocatalyst with a dendrimer template containing ionic liquid is presented. Magnetic silica nanoparticles were prepared using the Stober method. Their surface was modified with the help of cyanuric chloride, melamine, and 1-methylimidazole as Linkers. Finally, the nanocatalyst was decorated with affordable copper metal. The dendrimer-templated nanocatalyst was identified by different analyses, such as FT-IR, SEM, TEM, XRD, EDX, TGA, CHN, and ICP-OES. Fe3O4@SiO2@NTMP-IL-Cu was used as a heterogeneous nanocatalyst with good performance and reusable in coupling syntheses. The synthesis of A3-coupling and Ullmann coupling was performed under solvent-free and THF conditions, respectively, with high yields. Reusability and high efficiency of products in the vicinity of this catalyst, the use of cheap and available metal are desirable features of this synthetic catalyst.

Green Synthesis of Some 2‐Amino‐4 h‐Benzo[H]Chromene Derivatives in the Presence of Bimetallic Nanocomposite Based on Magnetic Mesoporous Silica Nanoparticles at Ambient Conditions

AbstractIn this research, some of 2‐amino‐4H‐benzo[h]chromene derivatives were synthesized by multicomponent reaction of 1‐naphthol, benzaldehyde derivatives and malononitrile. The reaction was performed under green conditions using water as the solvent in the presence of heterogeneous nano catalyst containing Co(II) and Cu(II) stabilized on magnetic mesoporous silica nanoparticles/tannic acid (M–MSN/TA/Co(II),Cu(II)) at room temperature. The prepared catalyst showed excellent efficiency and its magnetic properties allow easy separation. The structure and morphology of prepared catalyst was identified using Fourier transform infrared (FT‐IR), X‐ray diffraction (XRD), field emission scanning electron microscopy (FE‐SEM), energy dispersive X‐ray spectroscopy (EDX), elemental mapping, thermogravimetric analysis (TGA) and vibrating‐sample magnetometry (VSM) analysis. All of products were obtained in high to excellent yields (78–94 %) after short reaction times (20–45 min) in optimal conditions and their structures were confirmed using FT‐IR and Proton nuclear magnetic resonance (1H NMR) spectroscopic techniques. This study shows that the M–MSN/TA/Cu(II), Co(II) presents a good catalytic activity, reusability and stability compared to other catalysts.

Green Approach for the Synthesis of 2-Phenyl-2H-indazoles and Quinazoline Derivatives Using Sustainable Heterogeneous Copper Oxide Nanoparticles Supported on Activated Carbon and OER Study.

This research work reports the synthesis of copper oxide (CuO) nanoparticles supported on activated carbon by a simple impregnation method using 2-propanol as a green solvent, followed by calcination. The synthesized CuO@C is used as an efficient heterogeneous nanocatalyst for the synthesis of 2H-indazoles and quinazolines utilizing commercially available 2-bromobenzaldehydes, primary amines, and sodium azide under ligand-free and base-free conditions. The present methodology demonstrates the formation of new N-N, C-N, and C═N bonds under one-pot reaction conditions using PEG-400 as a green solvent. The reaction pathways are supported by control experiments and mechanistic elucidation. Further, the synthesized catalyst was characterized by a range of microscopic and spectroscopic techniques such as powdered X-ray diffraction, fourier transform infrared spectroscopy, field emission scanning electron microscopy, energy-dispersive X-ray, UV-vis, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, and BET-BJH analysis. Importantly, the study focused on the recyclability of the catalyst and successfully showed gram-scale production. Significantly, our active catalyst exhibited an outstanding performance in the oxygen evolution reaction, with an overpotential of 290 mV and a swallow Tafel slope of 91 mV dec-1.

Green Synthesis of New Derivatives of Iminothiazole Using Cefixime and Removing Organic Pollutants from Aqueous Environment by Employing Cu@KF/Clinoptilolite NPs.

In this research, multicomponent reactions of cefixime, isothiocyanates, and alkyl bromides were carried out for the synthesis of new iminothiazole derivatives with high yields in water as the solvent at room temperature in the presence of catalytic amounts of Cu@KF/CP NPs as catalysts. Also, the ability of Cu@KF/Clinoptilolite nanoparticles (NPs) to adsorb and remove 4-NP and cefixime from water was investigated. The Cu@KF/Clinoptilolite nanoparticles were synthesized by employing a water extract of Petasites hybridus rhizomes. For this experiment, all of the components obtained from Fluka and Merck were subjected to further purification. The antibiotic used in this investigation, cefixime, was obtained from a pharmaceutical facility situated in Sari, Mazandaran, Iran. The antibiotic factory is located in Sari City, Iran. All solutions were prepared using distilled water. The shape of Cu@KF/CP nanoparticles was analyzed using images obtained from a Holland Philips XL30 scanning electron microscope. An analysis was performed on the crystalline structure of Cu@KF/CP nanoparticles (NPs), and a room temperature X-ray diffraction (XRD) examination was carried out utilizing a Holland Philips Xpert X-ray powder diffractometer. The X-ray diffraction (XRD) examination was conducted using CuK radiation, which has a wavelength of 0.15406 nm. The analysis covered a 2ε angle range from 20 to 80°. The nanostructures that were produced were chemically analyzed using X-ray energy dispersive spectroscopy (EDS) with an S3700N equipment. The morphology and dimensions of Cu@KF/CP nanoparticles were characterized using a Philips EM208 transmission electron microscope operated at an acceleration voltage of 90 kV. The primary objective of this study was to develop a sustainable approach for producing new iminothiazole derivatives 4. This was achieved using a highly efficient three-component reaction combining cefixime 1, isothiocyanates 2, and alkyl bromides 3. The reaction was carried out in water at ambient temperature, using Cu@KF/CP NPs as a highly effective catalyst, leading to excellent yields. Moreover, the study findings showed that the synthesized compounds demonstrated a significant antioxidant activity compared to conventional antioxidants. The antibacterial efficacy of the synthesized compounds was evaluated against both Gram-positive and Gram-negative bacteria. Furthermore, Cu@KF/CP nanoparticles were utilized to adsorb CFX and 4-NP from water-based solutions. This study showcases the effective synthesis of innovative iminothiazole derivatives through the use of multicomponent reactions, involving the combination of cefixime, isothiocyanates, and alkyl bromides. The reactions were conducted in a water-based solvent. The reactions were carried out at room temperature, utilizing Cu@KF/CP NPs as catalysts. The Cu@KF/CP nanoparticles, a newly developed heterogeneous nanocatalyst, were synthesized and evaluated utilizing X-ray diffraction (XRD), fieldemission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM) research techniques. Cu@KF/CP nanoparticles are utilized to adsorb CFX and 4-NP from water-based solutions. The objects were manufactured using a straightforward and uncomplicated approach. The BET surface area of Cu@KF/CP NPs was measured to be 201.8 m2/g. The experimental equilibrium data was evaluated by applying the isotherms of the Langmuir, Freundlich, Dubinin-Radushkevich, and Redlich-Peterson models. Additionally, we examined the catalytic efficiency of Cu@KF/CP nanoparticles (NPs) in reducing various colors in water.

Integrating environmental remediation with biodiesel production from toxic non-edible oil seeds (Croton bonplandianus) using a sustainable phyto-nano catalyst

In the current situation of the environmental uprising toxicology, rising global temperature, and energy-depleting urges to explore and discover more renewable and greener ecological-benefiting energy resources. Biobased renewable fuels generated by using waste products can help in waste management, climate change mitigation, and a low-carbon future. The main objective of this research is to produce environment-friendly and cost-effective biofuel. The potentiality of the novel, toxic, waste, and inedible feedstock Croton bonplandianus was evaluated for biodiesel synthesis through transesterification utilizing a Phyto-nano catalyst of potassium oxide prepared by Croton bonplandianus floral stalk's aqueous extract focusing on waste management. Phyto-nano catalyst characterization was done through innovative tools such as Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Zeta Potential (ZP), X-Ray Diffraction (XRD), Fourier Transformed Infrared spectroscopy (FTIR), and Diffuse Reflectance Spectroscopy (DRS). The characterization results revealed that the potassium oxide phyto-nanocatalyst possesses an average nanoparticle size of 44.5 nm. This size is optimal for enhanced catalytic activity, indicating significant potential for efficient catalysis. The highest yield (94 %) of biodiesel was secured at optimized reaction conditions of catalyst quantity (0.50 wt%), reaction time (180 min), methanol: oil ratio (9:1), and reaction thermal point (70 °C). Transformation of triglycerides to methyl esters was confirmed by GC/MS, NMR, and FTIR techniques. A total of 21 methyl esters were observed in Croton bonplandianus biodiesel confirmed via GC/MS results. Evaluation of fuel properties was done and matched with international fuel standards. The conclusive remarks for the conducted research are that Croton bonplandianus has a high potential for biodiesel production by applying Phyto-nanocatalysts of potassium oxide while dealing with hazardous environmental conditions and waste management. Phyto nanocatalyst of potassium oxide can be reused and gives the same yield after several cycles of reusability, this reusability of heterogenous Phyto nanocatalyst can reduce to total cost of biodiesel production and can contribute towards circular economy.

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.

WITHDRAWN: rGO@CaO/NiO as a bifunctional heterogeneous nanocatalyst for high-quality biodiesel production from degraded waste oil by microwave-assisted: Diesel engine parameters assessment

In this research, a highly effective rGO@CaO/NiO bifunctional nanocatalyst was synthesized and utilized for the generation of biodiesel from degraded waste oil (DWO) through microwave assistance. A comprehensive analysis was conducted to assess the catalyst structure, revealing a notable specific surface area with significant surface characteristics for the rGO@CaO/NiO bifunctional nanocatalyst. The maximum biodiesel yield was achieved 97.46% under optimum conditions including methanol to oil ratio of 11.1 mol/mol, catalyst content of 3 wt.%, microwave time of 7.5 min, and stirring speed of 700 rpm. The catalyst's reusability was demonstrated through multiple cycles, maintaining high stability and consistent biodiesel yield over seven iterations. The activation energy and exponential factor for the conversion of DWO to biodiesel were determined as 30.91 kJ/mol and 2.3×104 min-1, respectively. The physical attributes of DWO-derived biodiesel revealed that they fall within the ASTM D6751 standard range. The impact of adding biodiesel to petrodiesel/biodiesel blends at various torques on the emission of key pollutants (CO, NOx, CO2, and UHC) and engine performance (BP, EGT, BTE, and BSFC) was investigated, yielding promising results. The rGO@CaO/NiO appears as a superior choice for biodiesel production, offering exceptional reusability, and significant biodiesel efficiency achieved within a short reaction time.

Synthesis of Pyrrolo [2,1-a]isoquinolines using Cu NPs decorated microcrystalline cellulose in 2-Methyl-THF: A biodegradable heteregeneous nanocatalyst for the sustainable cascade approach

Copper nanoparticles (Cu NPs) supported on microcrystalline cellulose (MCC) serve as an efficient and biodegradable heterogeneous nanocatalyst for the synthesis of pyrrolo [1,2a] isoquinoline under mild and sustainable reaction conditions through a cascade reaction involving condensation, addition, oxidation, and cyclization events. The catalyst underwent thorough characterization via various techniques, including FT-IR, PXRD, XPS, FE-SEM, EDX, TEM, and HR-TEM analysis. Optimized reaction conditions facilitated high-yield production of a diverse range of pyrrolo [1,2a] isoquinolines in 2-Me THF solvent, and the method demonstrated scalability with successful gram-scale synthesis. Notably, the catalyst exhibited reusability for up to five cycles without a significant decrease in activity. This approach aligns with eco-friendly principles, as evidenced by favorable green chemistry metrics for compound 4a, including low process mass intensity (7.83), a minimal environmental impact factor (6.83), a substantial atom economy (67.56 %), efficient reaction mass efficiency (60.76 %), high chemical yield (92.37 %), low mass intensity (1.64), notable mass productivity (60.97 %), considerable carbon efficiency (69.15 %), and optimum efficiency (89.93 %). These results highlight the sustainable and environmentally conscious nature of the developed synthetic methodology.

One-pot conversion of 2-ethoxycarbonyl-4H-3,1-benzoxazine-4-ones to tetracyclic quinazoline-6,12-diones in the presence of a Pd complex nanocatalyst

Abstract Heterocyclic transformation of 2-ethoxycarbonyl-4H-3,1-benzoxazine-4-ones to new derivatives of tetracyclic quinazoline-4-ones has been investigated with MCM-41‐dtz‐Pd as a heterogeneous recoverable nanocatalyst under mild reaction conditions.

Expression of concern: Copper nanoparticle anchored biguanidine-modified Zr-UiO-66 MOFs: a competent heterogeneous and reusable nanocatalyst in Buchwald-Hartwig and Ullmann type coupling reactions.

Expression of concern for 'Copper nanoparticle anchored biguanidine-modified Zr-UiO-66 MOFs: a competent heterogeneous and reusable nanocatalyst in Buchwald-Hartwig and Ullmann type coupling reactions' by Hojat Veisi et al., RSC Adv., 2021, 11, 22278-22286, https://doi.org/10.1039/D1RA02634H.

Kinetic and optimization study of ultrasound-assisted biodiesel production from waste coconut scum oil using porous CoFe2O4@sulfonated graphene oxide magnetic nanocatalysts: CI engine approach

In this study, CoFe2O4@sulfonated graphene oxide (SGO) heterogeneous nanocatalyst was synthesized and utilized to produce biodiesel from waste coconut scum oil (WCSO). The structural features of CoFe2O4@SGO nanocatalyst were evaluated by SEM, TEM, EDX, FTIR, XRD, CO2/TPD, VSM, and BET analyses. According to these analyses, CoFe2O4@SGO nanocatalyst has high specific surface area, suitable functional groups, and good reactivity. The highest biodiesel yield using CoFe2O4@SGO nanocatalyst in optimal conditions (MeOH/WCSO ratio = 12.41, temperature = 64.73 °C, catalyst concentration = 2.24 %, and ultrasonic time = 33.08 min) was 96.87 %. The yield of biodiesel decreased from 96.91 % to 90.17 % after six reuse cycles, which demonstrates the significant stability of CoFe2O4@SGO nanocatalyst in the transesterification process. After 7 reuse steps, XRD and CO2/TPD analyzes revealed that the catalytic activity and crystallinity of the nanocatalyst were almost retained. The kinetic behavior of biodiesel generation showed that the transesterification reaction is endothermic. Enhancing the concentration of biodiesel in the fuel mix had a positive impact on the reduction of CO and UHC emissions, as well as diesel engine parameters such as cylinder pressure, BP, EGT, BSFC, and BTE. Owing to the high biodiesel yield, significant reusability, and positive impacts on the diesel engine, CoFe2O4@SGO nanocatalyst is recommended for industrial applications.

Green synthesis and characterization of trisubstituted imidazole derivatives by an ecofriendly and efficient heterogenous nanocatalyst based on magnetite nanoparticles coated modified nanocellulose

In the present work, a nanocellulose based magnetic nanocomposite [(pH-PDA-DANC)@Fe3O4NPs] was synthesized by an ecofriendly and a simple protocol and characterized by means of different techniques such as Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), Thermal Gravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) equipped with an Energy Dispersive X-ray (EDX) probe and the Value Stream Mapping (VSM). The theoretical study of [(pH-PDA-DANC)@Fe3O4NPs] was investigated using Density Functional Theory (DFT) at the DFT-D3/ B3LYP/LanL2DZ level of theory to explore the nature of the interactions between the (pH-PDA-DANC) ligand and magnetite nanoparticles. The results indicate that the Fe3O4 nanoparticles form covalent bonds with the N-ring of the ligand. Then, it was used as a catalyst in the green and efficient procedure for one-pot multicomponent syntheses of imidazole derivatives by the condensation of benzil or 9.10-phenanthrenequinone, benzaldehyde derivatives and ammonium acetate. The catalytic reaction provided the synthesis of above imidazole derivatives with high reaction efficiency (80 %-98.1 %) in a short reaction time (3 h) and in presence of a minimum amount of ethanol. The identification and structure of imidazole derivatives was determined analyzing the 1H NMR (Nuclear Magnetic Resonance) and FTIR spectra. This procedure has several advantages compared to the conventional method such as the high yields, short reaction times, easy separation of the nanocatayst from the reaction mixture by using a magnet, and the reusability of the catalyst.

Synthesis and Antimicrobial Activity of (E)-1-Aryl-2-(1H-tetrazol-5-yl)acrylonitrile Derivatives via [3+2] Cycloaddition Reaction Using Reusable Heterogeneous Nanocatalyst under Microwave Irradiation.

The magnetically recoverable heterogeneous Fe2O3@cellulose@Mn nanocomposite was synthesized by a stepwise fabrication of Mn nanoparticles on cellulose-modified magnetic Fe2O3 nanocomposites, and the morphology of the nanocomposite was characterized through advanced spectroscopic techniques. This nanocomposite was investigated as a heterogeneous catalyst for the synthesis of medicinally important tetrazole derivatives through Knoevenagel condensation between aromatic/heteroaromatic aldehyde and malononitrile followed by [3+2] cycloaddition reaction with sodium azide. Thirteen potent (E)-1-aryl-2-(1H-tetrazol-5-yl)acrylonitrile derivatives are reported in this paper with very high yields (up to 98%) and with excellent purity (as crystals) in a very short period (3 min @ 120 W) using microwave irradiation. The present procedure offers several advantages over recent protocols, including minimal catalyst loading, quick reaction time, and the utilization of an eco-friendly solvent. Furthermore, the synthesized (E)-1-aryl-2-(1H-tetrazol-5-yl)acrylonitrile derivatives (4b, 4c, and 4m) are shown to have excellent resistance against various fungal strains over bacterial strains as compared to the standard drugs Cefixime (4 μg/mL) and Fluconazole (2 μg/mL).

Ultrafine copper oxide nanoparticles immobilized on poly (4-vinylpyridine)-grafted UiO-66-NH2 as heterogeneous catalyst for oxidative homocoupling of terminal alkynes

Terminal alkyne homocoupling is an effective route to synthesize 1,3-diynes, which are crucial components of many fine chemicals and natural products. However, the reaction often faces challenges of catalyst recovery and typically necessitates the introduction of basic additives, which limits its practical applicability. Here, we have developed a green and efficient Cu2O@UiO-66-g-P4VP nanocatalyst that exhibits outstanding activity for homocoupling terminal alkynes under mild, base- or ligand-free conditions. The characterization results indicate that the nitrogen atoms in P4VP interfere with the electronic structure of Cu in Cu2O nanoparticles, causing the N electrons to shift onto Cu. Density functional theory (DFT) calculations suggest that this catalytic system facilitates the activation of oxygen on the copper surface, promoting the coupling reaction. This work provides a feasible strategy for the rational fabrication of MOF-supported polybase and Cu2O nanocrystals as heterogeneous nanocatalysts in the oxidative homocoupling of alkynes.

Effect of Calcination Temperature on the Surface of Prepared ZnO Nanocatalysts

ZnO nanoparticles (NPs) having nsemiconducting properties are important nanocatalysts for many surface reactions. Because of their extensive use as heterogeneous nanocatalyst for energy production and environmental cleaning, it is essential to understand their surface properties to design better chemical and photochemical nanocatalysts. Here, we used the sol-gel method to develop numerous ZnO NPs at various calcination temperatures (300 - 800 oC) and analyzed by different surface characterization techniques such as FTIR, SEM, XRD and UV-visible absorption spectroscopy. To investigate the catalytic activity a series of photooxidation studies on Remazol Red RR (RRR) were carried out at different conditions. From the surface characteristic analysis, it is found that the crystalline ZnO NPs are formed at above 400 oC temperature. The highest photocatalytic efficiency is found at 500 oC which might be related to the lowest particle size (35.4 ± 5.2 nm) and surface heterogeneity. The experimental results suggest that temperature-controlled growth rate and intra/inter-particle heterogeneity of ZnO nanoparticles have a great impact on the surface properties and photocatalytic activity. In addition to surface area, surface defects and crystal deformation may have a considerable impact on the photocatalytic activity by ZnO NPs. Finally, this study will help to understand what type of surface properties need to optimize to design industrial suit ZnO nanocatalysts. Journal of Engineering Science 15(1), 2024, 75-81

Ruthenium(III) unsymmetrical Schiff base complex supported on γ-Fe2O3 magnetic nanoparticles: A new heterogeneous nanocatalyst for efficient oxidation of hydrocarbons with tert-butyl hydroperoxide

In the present work, an unsymmetrical salen-type ruthenium(III) complex, Ru(salenac)Cl, where the unsymmetrical tetradentate Schiff base H2salenac = salicylideneiminoethyliminopentane-2-one, was synthesized and anchored on the surface of aminopropyl-functionalized silica-coated γ-Fe2O3 magnetic nanoparticles. The characterization of the resulting γ-Fe2O3@SiO2@APTES@Ru(salenac)Cl nanoparticles was performed using XRD, FT-IR, VSM, TGA, ICP, TEM, BET, SEM and EDX methods. The prepared γ-Fe2O3@SiO2@APTES@Ru(salenac)Cl magnetic nanoparticle was successfully employed as an efficient heterogeneous nanocatalyst for alkenes epoxidation and alkanes oxidation with tert-butyl hydroperoxide (tert-BuOOH, 70 % aqueous solution) as oxidant in acetonitrile at ambient temperature. In the mentioned catalytic system, the intended products were obtained with good to excellent yields along with high selectivity. The heterogeneous γ-Fe2O3@SiO2@APTES@Ru(salenac)Cl nanocatalyst can be recovered easily using an external magnet and recycled six times with no notable decrease in catalytic activity. Moreover, FT-IR, XRD, SEM and EDX techniques were used to characterize the recovered γ-Fe2O3@SiO2@APTES@Ru(salenac)Cl nanocatalyst and it was demonstrated that the catalyst maintained its structure intact following the recovery process.