Research on Chemical Intermediates最新文献

To resolve these dire environmental issues of today, it is imperative to develop highly effective and stable catalysts for the catalytic reduction of poisonous 4-nitrophenol (4-NP) to more useful and readily biodegradable 4-aminophenol (4-AP). Herein, we present a Cu₂O nanoparticle-immobilized Ti-based metal–organic framework MIL-125-NH₂ composite catalyst (Cu₂O/NM), which was synthesized by facile coordination combined with an in situ reduction process. The Cu₂O/NM catalyst has exhibited good catalytic performances in the reduction of 4-NP, with a rate constant of 3.524 min⁻¹ and an activation energy (E_a) of 50.06 kJ mol⁻¹, comparable to other reported Cu-based catalysts and even noble metal-based catalysts. The higher catalytic performance of Cu₂O/NM can be ascribed to the high adsorption ability of NM and high effective electron transfer due to the Cu²⁺/Cu⁺ and Ti⁴⁺/Ti³⁺ redox couples (part of the Ti⁴⁺ in the NM was reduced to Ti³⁺ by NaBH₄). Furthermore, it demonstrates exceptional recyclability and structural stability, highlighting its potential as an effective and durable catalyst for practical applications. Based on the composition, structure, and catalytic performance of Cu₂O/NM, a plausible reaction mechanism is proposed. Therefore, this study presents a new paradigm for the fabrication of MOF-based composite catalysts with high catalytic activity and stability for the treatment of 4-NP-containing wastewater.

The global community is grappling with a pressing concern: The dwindling availability of unpolluted water sources. Human endeavours have led to the degradation of pure water, aggravating this crisis. In the current study, Eu and La co-doped SnO₂ nanoparticles were successfully synthesized by a simple wet-chemical method. XRD analysis reveals the increased micro-strain and dislocation density of the composite sample when compared with pure SnO₂. HRTEM of the composite sample evidenced a rice-like morphology with an average particle size of 14.49 nm. Chemical states of Sn, O, Eu and La were obtained from XPS analysis. The Raman spectra further confirm the formation of tetragonal SnO₂. The band gap of SnO₂ reduced from 2.12 to 1.90 eV when co-doped with Eu and La. Consequently, the resulting Eu and La co-doped SnO₂ degraded 83% and 99.6% of the crystal violet dye under visible light and UV light, respectively, as compared to SnO₂, Eu-doped SnO₂ and La-doped SnO₂ nanoparticles under visible and UV light irradiations. These co-doped Eu and La co-doped SnO₂ nanostructures prepared as such can be exploited for the development of UV–Visible driven photocatalysts in the domain of environmental remediation.

This study investigated the effect of metal dopants on the surface properties of ZnO-based catalysts for the transesterification of propylene carbonate (PC) with methanol to produce dimethyl carbonate (DMC). A series of metal-doped ZnO nanocatalysts (M-ZnO, where M is Ca²⁺, Cu²⁺, Ce³⁺, La³⁺, and Y³⁺ with the mol ratio of Zn²⁺/M^x+  = 4) were prepared by a simple co-precipitation method followed by calcining in air at 673 K for 5 h. Introducing different metal cations into the ZnO system decreased crystallite size and created surface defects of exposed cations and oxygen vacancies, increasing surface-active acid and basic sites. The catalytic performance for DMC production was ranked as follows: Ca-ZnO < Cu–ZnO < ZnO < Ce-ZnO < Y-ZnO < La-ZnO. La-ZnO showed the highest performance of all catalysts, with 67% PC conversion, 67% DMC selectivity, and 45% DMC yield. The improvement of catalytic activity was correlated with an increase in the concentration of moderate and strong acid–base functionalities on the La-ZnO surfaces for participating in the reaction of PC and methanol to form DMC.

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The CeO₂ impregnated carbon nanocomposite was fabricated using the simple ultrasonic dispersion method. The confirmation of elemental, structural and surface properties blended in the materials were investigated by various analytical techniques including XRD, FTIR, FESEM, TGA, BET, XPS and RAMAN spectroscopy. The porous nature of the material shows substantial increase in the catalytic activity thereby enhancing the reactivity of oxygen evolution at anode. The electrochemical measurements (Linear sweep voltammetry and Cyclic voltammetry) of the electrocatalyst show overpotential value of 350 mV and the computed Tafel slope value of 89 mV dec⁻¹ at the current density of 10 mA/cm² which makes CeO₂–Carbon nano catalyst as an excellent material for electrocatalytic OER activity. The electrochemical surface activity (ECSA) determined which shows the efficient deposition of aqueous electrolyte molecules on the surface of the electroactive material resulting in optimal concentration.

A novel Cu catalyst immobilized on glycine-functionalized poly(vinyl chloride) (Cu@Gly-PVC) was synthesized conveniently. The as-prepared catalyst was fully characterized by FTIR, SEM, EDS, elemental mapping, XPS, TGA, ICP, and EA analysis. The Cu(II) ions were uniformly distributed on the as-prepared Gly-PVC matrix via coordinated by carboxylic groups in a bidentate bridging pattern. This catalyst can be used at ppm levels in water for alkyne–azide cycloadditions (CuAAC) reactions, producing high yields of 1,2,3-triazoles. The present methodology offers several merits such as low catalyst loading, high catalytic activity, excellent yields, short reaction times, environmentally friendly reactions, simple operations, and compatibility of wide range of substrates. Furthermore, the catalyst can be easily isolated from the reaction mixture through simple filtration and retains remarkable reusability and catalytic activity even after four consecutive reaction cycles.

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Magnetic catalysts are known for their exceptional reusability and recyclability, which not only makes the process more cost-effective but also aligns with green chemistry principles. The use of magnetic catalysts in the synthesis of 2,4,5-triaryl imidazoles presents a sustainable, efficient, and versatile approach that aligns with the evolving demands of modern chemical synthesis. In this paper, we fabricated Fe₃O₄@SiO₂-ABMA-MnCl₂ nanocomposite as a novel and recoverable nanocatalyst for the synthesis of 2,4,5-triaryl imidazoles through the three-component reaction of various derivatives of aromatic and heteroaromatic aldehydes with benzil derivatives and ammonium acetate in ethylene glycol. Under this catalytic system, a broad spectrum of triaryl imidazole derivatives was afforded with high to excellent yields in less than 1 h. Several spectroscopic techniques well identified the structure of Fe₃O₄@SiO₂-ABMA-MnCl₂ nanocomposite. Conducting reactions in ethylene glycol as a solvent, synthesis of products with excellent efficiency in less than one hour, very good identification of the catalyst structure, simple separation of the catalyst from the reaction mixture, and its high reusability are some of the valuable features of this catalytic system. VSM, TGA, ICP-OES analyzes showed that the Fe₃O₄@SiO₂-ABMA-MnCl₂ catalyst has high stability and has maintained its magnetic nature and structure after recovery (despite 8 consecutive uses).

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In synthetic chemistry, cycloaddition is a valuable tool for creating heterocyclic rings, with numerous applications in a variety of fields. The objective of this research is to develop a NiCu/ZIF-8 catalyst to facilitate a three-component reaction known as the "click reaction," which is used to synthesize 1,2,3-triazoles. The catalyst was designed to catalyze 1,3-dipolar cycloaddition reactions involving several azides and alkynes. The metals nickel and copper were immobilized on the surface of ZIF-8 to maximize the catalyst's performance. The catalyst was characterized using various analytical methods, including scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDX). Remarkably, the catalyst demonstrated stability, maintaining its catalytic properties and efficiency after five recycling cycles. The advantages of this procedure are manifold, including high speed, mild conditions, reusability, high yield (75–95%), and affordability, which make it an attractive method for 1,3-dipolar cycloaddition reactions.

A highly organized and green protocol has been developed for fabricating amino methylene bisphosphonates using sulfated choline ionic liquid (SCIL) catalyzed under ultrasonication. This method involves various substituted amines, triethyl orthoformate, and diethyl phosphite. All synthesized derivatives were characterized by Nuclear Magnetic Resonance NMR (¹H and ¹³C), confirming product formation. This approach significantly enhances the synthesis of desired products with high yields. The choline is biodegradable and it was widely used to prepare deep eutectic solvents and to synthesis of ionic liquid to replace the Cl⁻ ion to hydroxide ion it gives good basicity, and modification of terminal hydrogen is replaced by ClSO₃H it gives good acidity; hence the choline-based catalyst can use in both acid and base promoted reaction. The synthesized SCIL was characterized using by Fourier transform infrared (FT-IR), Thermogravimetric analysis (TGA), X-ray diffraction (XRD) and Scanning electron microscope (SEM) demonstrating the functionalization of the sulfonate group to form an effective acidic ionic liquid.Please confirm if the author names are presented accurately and in the correct sequence (given name, middle name/initial, family name). Author 2 Given name: [Reddi Mohan Naidu] Last name [Kalla], Author 3 Given name: [Araveeti Eswar] Last name [Reddy] and Author 4 Given name: [Tahani Mazyad] Last name [Almutairi]. Also, kindly confirm the details in the metadata are correct.Yes the author detials were correct

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A green and efficient synthesis of novel cyclohexanone diesters was achieved via the double addition of dimethylmalonate to dibenzylideneacetone derivatives in the presence of imidazolium-based ionic liquids as catalysts, without the use of any base. Ionic liquids were synthesized by anion exchange with various organic acid salts. The reaction was optimized by evaluating the effects of various ionic liquids. Among the tested ionic liquids, 1,3-dibutyl-2-methylimidazolium hydroxide ([Dbmim][OH]) demonstrated the highest catalytic performance, yielding up to 99% of the desired products in ethanol as the solvent. The study highlighted the remarkable dual benefits of ionic liquids, showcasing their outstanding catalytic efficiency along with significant environmental advantages, positioning them as a sustainable, eco-friendly, and reusable alternative for the base-free synthesis of cyclohexanone diesters.

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