Microwave-assisted preparation of polysubstituted imidazoles using Zingiber extract synthesized green Cr(2)O(3) nanoparticles

A High-Performance Cr2O3/CaCO3 Nanocomposite Catalyst for Rapid Hydrogen Generation from NaBH4

This study aims to prepare new nanocomposites consisting of Cr2O3/CaCO3 as a catalyst for improved hydrogen production from NaBH4 methanolysis. The new nanocomposite possesses nanoparticles with the compositional formula Cr2-xCaxO3 (x = 0, 0.3, and 0.6). These samples were prepared using the sol-gel method, which comprises gelatin fuel. The structure of the new composites was studied using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, environmental scanning electron microscopy (ESEM), and X-ray spectroscopy (XPS). The XRD data showed the rhombohedral crystallinity of the studied samples, and the average crystal size was 25 nm. The FTIR measurements represented the absorption bands of Cr2O3 and CaO. The ESEM micrographs of the Cr2O3 showed the spherical shape of the Cr2O3 nanoparticles. The XPS measurements proved the desired oxidation states of the Cr2-xCaxO3 nanoparticles. The optical band gap of Cr2O3 is 3.0 eV, and calcium doping causes a reduction to 2.5 and 1.3 eV at 15.0 and 30.0% doping ratios. The methanolysis of NaBH4 involved accelerated H2 production when using Cr2-xCaxO3 as a catalyst. Furthermore, the Cr1.7Ca0.3O3 catalyst had the highest hydrogen generation rate, with a value of 12,750 mL/g/min.

Magnetically retrievable nanocatalyst Fe3O4@CPTMO@dithizone-Ni for the fabrication of 4H-benzo[h]chromenes under green medium

In the research, the core-shell procedure synthesized a novel magnetically separable heterogeneous nanocatalyst with high stability named Fe3O4@CPTMO@dithizone-Ni. In this method, Fe3O4 was modified as a magnetic core using surfactant (SDS) and polyethylene glycol (PEG) coating; after functionalizing the magnetic nanoparticles with 3-chloropropyl-tri-methoxysilane and dithizone, Ni metal was immobilized. The prepared catalyst was identified and specified utilizing diverse physicochemical techniques involving FT-IR, XRD, SEM, EMA, BET, ICP, EDS, TGA, Raman, and TEM. In the following, to vouch for the efficiency of the obtaining catalyst for the green synthesis of 4H-benzo[h]chromenes utilizing the three-component, one-pot condensation reaction of α-naphthol, aryl glyoxal, and malononitrile as precursors were evaluated. The catalyst exhibited high recyclability with a slight reduction in activity at least eight series without a substantial decrease in stability and efficiency. The synthesized nanocatalyst was evaluated in various conditions such as different solvents, etc. the best of these conditions is the initial concentration of 30 mg of nanocatalyst with water as a solvent in 3 min with 98% yield. The prominent merits of the present research include easy separation of the catalyst without centrifugation, high-accessible raw precursors, cost-effectiveness, environmental friendliness, green reaction status, quick reaction, and excellent product yields.

Synthesis of Highly Heterocyclic Fluorescent Molecules: 2-imino-2H-pyrano[3,2-c] Pyridin-5(6H)-ones Derivatives

New highly fluorescent 2-imino-2H-pyrano[3,2-c]pyridin-5(6H)-onesderivatives were synthesized using a simple route. The present molecules were prepared by two methods with good yield. The structures were characterized by NMR1H, 13 C, and elemental analysis. Also, the effect of solvent and concentration on the fluorescence properties were demonstrated. However, the high fluorescence intensity in the range of 70,000-75,000 a. u. was obtained with a concentration equal to 10- 6 M of prepared molecules. The intensity was influenced also by the molecule structure and solvent.

Green Synthesis of Aromatic Nitrogen-Containing Heterocycles by Catalytic and Non-Traditional Activation Methods

Recent advances in the environmentally benign synthesis of aromatic N-heterocycles are reviewed, focusing primarily on the application of catalytic methods and non-traditional activation. This account features two main parts: the preparation of single ring N-heterocycles, and their condensed analogs. Both groups include compounds with one, two and more N-atoms. Due to the large number of protocols, this account focuses on providing representative examples to feature the available methods.

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.

Fe3O4@Glycerol-Cu as a novel heterogeneous magnetic nanocatalyst for the green synthesis of 2-amino-4H-chromenes

In the present study, the Fe₃O₄@Glycerol-Cu complex supported magnetically as a nanoparticle was prepared by grafting. Firstly, Fe₃O₄ NPs were synthesized by FeCl₃.6H₂O and FeCl₂.4H₂O according to the reported method, and subsequently, the prepared MNP with 3-chloropropyltrimethoxysilane. After that, the support-glycerol was functionalized on the surface of MNP-(CH₂)₃Cl for graft and stabilization of copper metal. Our purpose is to use the Fe₃O₄@Glycerol-Cu as a green, recoverable, novel, and affordable nanocatalyst in the effective synthesis of 2-amino-4H-chromenes. FT-IR, XRD, TGA, BET, VSM, TEM, and SEM-EDX techniques were examined to characterize this nanocatalyst. This result demonstrates that copper and organic compounds have appropriately reacted, with the support of MNP-(CH₂)₃Cl, and the crystalline structure have preserved in the MNP-(CH₂)₃Cl/Glycerol-Cu nanocatalyst confirmed the formation of the base Cu complex grafted on the surface of the nanoparticles. Finally, as can be seen, the nanoparticle size is 5-15 nm. This heterogeneous nanocatalyst illustrated excellent recyclable behavior, and can be used several times without notable reduction of its activity.