Research on Chemical Intermediates最新文献

This study investigates the application of the Fe₃O₄/SiO₂/TiO₂ magnetic nanocomposite for the facile and recyclable production of phosphines. The nanocomposite was fabricated by combining the magnetic properties of Fe₃O₄, the structural stability of SiO₂, and the catalytic activity of TiO₂, and was subsequently characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), Brunauer–Emmett–Teller analysis (BET), vibrating sample magnetometry (VSM), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). As a heterogeneous catalyst, this nanocomposite provides high efficiency under mild reaction conditions in phosphine production. Its easy separation using a magnetic field, together with its reusability, makes this approach a sustainable solution in green chemistry. Overall, the findings demonstrate that Fe₃O₄/SiO₂/TiO₂ magnetic nanocomposites can significantly contribute to the development of efficient and environmentally friendly industrial processes for phosphine.

Aromatics, which are widely used as basic feedstock in industrial production, have traditionally been derived mainly from petroleum resources. Producing aromatics from furan-based molecules via Diels–Alder (D-A) cycloaddition offers a highly promising renewable route to reduce reliance on petroleum resources. Conventional solid acids such as zeolites and MOFs often promote the hydrolysis of DMF, leading to its polymerization and coke deposition, thereby reducing DMF utilization efficiency. Moreover, the structure–activity relationship in this reaction has not been fully elucidated. This study presents a novel supported tungsten–phosphorus catalyst that exhibits high catalytic activity and selectivity while effectively suppressing DMF hydrolysis and improving its utilization efficiency. This study also provides a detailed elucidation of the influence of both the ratio and the relative positions of Brønsted and Lewis acid sites on the reaction. Specifically, under the reaction conditions of 200 °C and 15 h, the 25W-15P/SBA-15 catalyst achieved 88% DMF conversion and 98% aromatic selectivity, with a carbon balance of 85%. Besides, the study also revealed that the presence of a few amount of L acid sites can significantly reduce the apparent energies (E_a) of aromatics formation. When the amount of Lewis acid sites was further increased, the E_a of the reaction no longer decreased, and the reaction rate was controlled by the dehydration process occurring at the Brønsted acid sites. Moreover, when the L acid and B acid sites are too far apart, they cannot effectively achieve cooperative catalysis in the D-A conversion of DMF and AA.

Electrochemical reduction reaction of CO₂ (CO₂RR) to C₁ and C₂ products can be achieved on Cu-based electrocatalysts. C₂ products exhibit higher energy density and economic value compared to C₁ products, making them more desirable as reduction products. However, the production of C₂ products on pure Cu catalysts involves multi-step proton-coupled electron transfer and C–C coupling steps, which are kinetically slow and result in poor catalytic activity and selectivity for the products. The cavity nanocubes Cu₂O(0.13-AA), Cu₂O(0.10-AA) and Cu₂O(0.15-AA) catalysts were synthesized via wet chemical reduction by adjusting the concentration of the reducing agent. The electrochemical pre-reduction method was used to obtain Cu₂O/Cu(0.13-AA), Cu₂O/Cu(0.10-AA) and Cu₂O/Cu(0.15-AA) catalysts for CO₂RR. Cu₂O/Cu(0.13 M-AA) catalyst achieves the high Faradaic efficiency (FE) of 39.98% for C₂H₄ and 54.76% for C₂ products (C₂H₄, C₂H₆, and C₂H₅OH), with significant inhibition of the hydrogen evolution reaction. In situ Raman experiments demonstrate that the cavity structure of the nanocubes enhances the local concentration of *CO intermediates, thereby promoting the C–C coupling process and improving the selectivity of CO₂ reduction to C₂ products.

We have developed an eco-friendly method for synthesizing hexahydroquinoline-3-carboxamide derivatives using guanidine hydrochloride as a catalyst in water. This one-pot, multicomponent reaction combines aromatic or heteroaromatic aldehydes, dimedone, acetoacetanilide, and ammonium acetate to produce high yields of the desired compounds. The catalyst also showed remarkable reusability, maintaining its effectiveness over five successive cycles without notable degradation. The approach boasts several advantages, including a sustainable reaction profile, streamlined processing, rapid reaction times, and efficient atom economy, making it an appealing and environmentally responsible approach.

Graphical abstract

Exploring environmentally friendly, highly economical, resource-saving, and recyclable low-temperature heterogeneous catalysts for liquid-phase organic reactions is of great significance for the realization of green and sustainable development. In this study, mesoporous polydivinylbenzene (PDVB)-based solid acid (PDVB-SO₃H) has been successfully prepared from sulfonation of mesoporous PDVB. And the sulfonated polymeric solid acid PDVB-SO₃H was used as for catalyzing Doebner–von Miller reaction for the synthesis of 1,10-phen with choline chloride as the co-catalyst for the first time. FT-IR and XPS confirmed successful sulfonate group grafting onto PDVB. N₂ sorption isotherms, SEM, and TG curves revealed the mesoporous PDVB-SO₃H possesses a high BET surface area, superior pore structure, and thermal stability. Besides, the results of acid–base titration and elemental analysis indicate that the extremely high acid capacity. Finally, the catalytic tests show that PDVB-SO₃H exhibits excellent catalytic activities and good recyclability in synthesis of 72% yield of 1,10-phen and the 1,10-phen yield did not decrease obviously after the PDVB-SO₃H catalyst was reused for 5 times. This work highlighted the excellent catalytic activity and good recyclability of PDVB-SO₃H, and provides a method and references to produce 1,10-phenanthroline.

The efficient degradation of dye pollutants continues to pose a significant challenge in wastewater treatment, primarily due to constraints in degradation efficiency and complications in catalyst recovery. To address these issues, a novel catalyst has been synthesized utilizing polyacrylonitrile fibers as a support material, which were subsequently loaded with iron-based metal–organic framework through a solvothermal approach. This catalyst, when combined with hydrogen peroxide (H₂O₂), forms a heterogeneous Fenton catalytic system that promotes the degradation of methyl orange (MO) in wastewater. A thorough investigation was conducted to examine the catalytic degradation performance of dyes and the underlying reaction mechanisms. The catalyst demonstrates outstanding performance in dye degradation, achieving 95.7% removal of methyl orange under ambient conditions. Moreover, it retains over 80% degradation efficiency after four consecutive reaction cycles, highlighting its strong recyclability and minimal loss of catalytic activity. Radical quenching experiments and electron paramagnetic resonance analyses confirm that the primary reactive oxygen species involved are hydroxyl radicals (·OH) and superoxide anions (·O₂⁻). Furthermore, both Fe^II and Fe^III ions can be recycled and regenerated in-situ, thereby continuously catalyzing H₂O₂ to produce ·OH and ·O₂⁻, which facilitates the sustained mineralization of dye molecules, thus enabling high dye degradation.

Graphical abstract

This work reports the environment-friendly synthesis of nature-derived biochar-based catalyst for synthesis of pharmaceutically significant 2,3-dihydroquinazolin-4(1H)-ones. A Magnetic biochar catalyst was synthesized from coconut waste using a simple hydrothermal reactor followed by 2-step functionalization steps to achieve sulphonated magnetic biochar, Fe@SO₃H-BC. The structural and morphological characterization of the synthesized catalysts was done using XRD, FTIR, FESEM and EDS. The catalytic activity of Fe@SO₃H-BC was studied for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones by condensation of 2-aminobenzamide with carbonyls including acetophenones and aldehydes in solvent-free conditions, resulting in moderate to high yields 83–94% and 70–95%, respectively. The methodology offered advantages by giving an operationally easier and greener chemical route for fabrication of environmentally derived biochar-based catalyst showing notable catalytic activity, recyclability and versatility.

Hydrogen is recognized as a clean and efficient energy carrier, and photocatalytic hydrogen generation represents a pivotal technology for sustainable energy development. In this work, a highly active noble metal-free ZnCo₂O₄/ZnO/C composite has been successfully synthesized via in situ carbonization of a ZnCo-based Prussian blue analogue (PBA), exhibiting remarkable photocatalytic hydrogen generation activity. Under simulated solar irradiation, the optimized composite achieves a high hydrogen generation rate of 2039.3 μmol/(g·h), along with excellent stability. The significantly enhanced photocatalytic activity originates from a unique S-scheme heterojunction charge transfer mechanism and multi-component synergistic effects. Specifically, the intimate interfacial contact among graphitic carbon, ZnCo₂O₄, and ZnO facilitates efficient separation and migration of photogenerated electron–hole pairs. The S-scheme mechanism not only preserves photogenerated electrons with strong reduction capability but also enhances charge carrier utilization. Furthermore, the graphitic carbon improves the electrical conductivity and light-harvesting capability. These factors are responsible for the remarkable photocatalytic performance and good stability. This work provides a compelling demonstration of utilizing PBA-derived carbonization as a versatile platform for fabricating efficient, stable, and scalable photocatalysts for practical hydrogen production.

Conventional synthetic methods for organic compounds are associated with significant environmental concerns, primarily due to the reliance on metal-based catalysts. Furthermore, the employment of toxic solvents combined with prolonged reaction durations presents substantial obstacles to the commercial scalability and practical application of these approaches. In this study, we developed a sustainable green electrode by functionalizing fullerene oxide with L-alanine and incorporating MIL-101@Fe metal–organic frameworks. This innovative approach is designed for enantioselective electro-organic carboxylation in a NaCl electrolyte. The study examines how the biocompatibility of L-alanine and the structural robustness of MIL-101@Fe enhance catalytic efficiency while maintaining environmental sustainability. Functionalizing fullerene oxide with L-alanine improves the electrode's selectivity for the desired enantiomers and increases electron transfer efficiency. The resulting catalytic substrate, oxC60-Ala-MIL101@Fe, was characterized employing various analytical techniques, including EDX, TGA, SEM, EDS, BET, CV, XPS, FT-IR, and DFT calculation to assess its morphology, thermal stability, elemental composition, surface area, and electrochemical behavior. To evaluate the electrode’s performance, we conducted the electro-organic carboxylation of ethylbenzene 1(a-l) derivatives under electro-organic synthesis conditions, yielding various (R)-2-phenylpropanoic acids 4(a-l) with excellent yields (92–97%). Optimal results were obtained at a current of 10 mA, over a duration of 2 h, and at room temperature and Ala-MIL101@Fe exhibited good performance for up to 9 cycles. The products were confirmed using ¹HNMR, CHN analysis, FT-IR spectroscopy, and melting point determination.

Graphical abstract

The generation of hydrogen gas through the catalytic hydrolysis of sodium borohydride (NaBH₄) has garnered significant interest in recent years. The primary research challenge remains the development of effective and reusable catalysts. This research details the development of Co/MnFe₂O₄ catalysts aimed at facilitating the hydrolysis of sodium borohydride (NaBH₄), employing MnFe₂O₄ as the support material. The support was synthesized through a co-precipitation method, while the catalysts were produced via an impregnation-chemical reduction technique. The characterization of the catalysts was performed using X-ray diffraction, field emission scanning electron microscopy, X-ray fluorescence, vibrating sample magnetometry, and nitrogen adsorption–desorption measurements. The study initially explored the effects of calcination temperature of the supports and the amount of loaded cobalt on the hydrogen generation process. Notably, catalysts supported on MnFe₂O₄ calcined at 400 °C demonstrated greater activity, with 30% Co/MF-400 catalyst yielding 3533 mL.min⁻¹.g_cat⁻¹of hydrogen during NaBH₄ hydrolysis. The enhanced catalytic performance of the MF-400 supported catalysts was attributed to their small crystallite size or prominent number of defects and high magnetic properties. In addition, 30Co-MF400 showed high specific surface area of 120.1 m².g⁻¹. Subsequently, various parameters were examined over 30Co/MF-400, including catalyst dosage (10–25 mg), concentrations of NaOH (1–7 wt.%), temperature (25–45 °C), and catalyst reusability. The activation energy (E_a) for the 30% Co/MF-400 catalyst was found to be 27.1 kJ/mol, as determined through the application of the rate expression and the Arrhenius equation. The 30% Co/MF-400 catalyst showed a 44% decline in catalytic performance after being used for four cycles.