Research on Chemical Intermediates最新文献

The widespread use of nuclear energy has led to a growing concern over environmental pollution resulted from uranium which has prompted global attention on wastewater treatment. Zero valent aluminum and zero valent nickel metals have been used by numerous researchers both domestically and internationally to removal U(VI) from aqueous solution due to their unique chemical properties. In this work, Al⁰/Ni⁰ bimetallic material (Al⁰/Ni⁰-BM) was prepared by synchronous liquid-phase reduction method. Due to the structure of bimetallic material and synergistic effect, it exhibited a higher removal rate compared with single zero valent metal. At room temperature (25 ℃), the initial concentration of U(VI) was 20 mg/L, pH was 3.0, dosage was 0.25 g/L, and the removal rate could reach 98.90% after 60 min of reaction, well-fitting with the pseudo-second-order kinetic model, reduction model, and Langmuir isothermal adsorption model. The high removal performance was attributed to the electron transfer mechanism between material and U element and the adsorption effect of corresponding hydroxides. The thermodynamic parameters demonstrated that the adsorption of U(VI) on the Al⁰/Ni⁰-BM was an endothermic and spontaneous process controlled by physical and chemical adsorptions. And the synthesized Al⁰/Ni⁰-BM effectively improved the aggregation of zero valent metals in monomers. In conclusion, Al⁰/Ni⁰-BM showed an excellent potential for U(VI) removal from aqueous solution by zero valent bimetallic materials.

Developing environmentally benevolent and sustainable approaches is a vital objective of research in any field. By upholding these parameters and strategizing the methodology, herein we report the development of a new heterogeneous nanocatalyst based on Schiff base functionalized Pd(II) complex onto titania-coated magnetic nanoparticles [Pd@SB/Fe₃O₄–TiO₂]. The developed catalytic system is well characterized with various techniques such as FE-SEM, TEM, XPS, XRD, TGA, BET, FTIR, VSM, CHN, EDX, and ICP-AES analysis. The catalytic activity of [Pd@SB/Fe₃O₄–TiO₂] for the Suzuki coupling reaction to synthesize biaryls and for the hydrogenation reaction of aromatic nitro compounds to synthesize aromatic amines under sustainable reaction conditions was tested which revealed excellent results. Pd@SB/Fe₃O₄–TiO₂ showed remarkably higher activity than the homogeneous PdCl₂ and Pd(OAc)₂, which might be due to the presence of electronic synergism between support and Pd. Schiff base functionalization provides excellent support to the palladium as leaching of the metal was not observed. The magnetic core of the catalyst ascertains its easy recoverability, thereby maintaining the sustainability of the reaction. The magnetic catalyst was easily separable with the help of an external magnet and showed very good recyclability for up to six cycles with no appreciable loss in catalytic efficiency. Furthermore, the reported catalyst remains unchanged even after six consecutive runs as established by the FTIR, XPS, and XRD analysis of the recovered catalyst.

Benzothiazole derivatives have high biological activity potential and are present in many natural and medicinal products. For these reasons, the synthesis of benzothiazoles is very important in organic synthesis. In this synthetic approach, we found that the utilization of Fe₃O₄@DOP-Amide/Imid-CuCl₂ nanocomposite in the presence of KOAc in ChCl-Urea as solvent is an eco-friendly and efficient catalytic system for the synthesis of 2-aryl benzothiazoles through one-pot three-component reactions of 2-iodoaniline and aromatic aldehydes with thiourea as sulfur source. Under this catalytic system, a broad spectrum of 2-aryl benzothiazoles were successfully synthesized with high to excellent yields. Compared to the reported catalysts or magnetic nanocatalysts, the Fe₃O₄@DOP-Amide/Imid-CuCl₂ nanocatalyst has the following series of features: design of a magnetic ligand through ammonolysis reaction, high magnetic property of the Fe₃O₄@DOP-Amide/Imid-CuCl₂ nanocatalyst, high catalytic activity in the synthesis of benzothiazole derivatives, reusability and high stability of the synthesized magnetic catalyst. The SEM, VSM, BET, and ICP-OES techniques revealed that the recovered Fe₃O₄@DOP-Amide/Imid-CuCl₂ catalyst (after 8 times) had high stability because the magnetic nature, structure, and surface of the recovered catalyst was similar to the fresh catalyst.

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NiO nanoparticles were assembled on the surface of Halloysite nanotubes, which were subsequently further functionalized by sulfonic acid, to create NiO@HNTs-SO₃H composite. This composite is employed as a heterogeneous catalyst in the one-pot synthesis of 1-(benzothiazolylamino) methyl-2-naphthols starting from aryl aldehyde, β-naphthol and 2-aminobenzothiazole as well as Tetrahydrobenzo[b]pyrans starting from aldehyde, dimedone and malononitrile. The catalyst was examined using Fourier transform infrared (FT-IR), energy dispersive X-ray (EDX), X-ray diffraction (XRD) pattern, and scanning electron microscopy (SEM) images. The synthesized organic compounds were examined using ¹H NMR and ¹³C NMR spectroscopy and mass analysis by HRMS. The most notable benefits of the current work are its straightforward setup, gentle reaction conditions, green solvents, excellent yields, ease of purification, high efficiency, and the use of a recoverable and environmentally friendly catalyst. The easy separation and reusability of NiO@HNTs-SO₃H catalyst after five runs confirmed the stability and effectiveness of the catalyst.

Graphical Abstract

The structures, stability and electronic properties of the Ni-doped boron nitride tubular clusters (NiB_m−1N_m), NH₃ adsorption on the NiB_m−1N_m (NH₃NiB_m−1N_m) and NH₃ embedded into the NiB_m−1N_m (NH₃@NiB_m−1N_m) (m = 48, 72 and 96) clusters have been investigated by using density functional theory. The results reveal that the diameters of the NiB_m−1N_m clusters have almost no effect on the NH₃ adsorption. The diameter of the NiB₄₇N₄₈ clusters is small enough to accommodate the NH₃ molecules, and the appropriate diameter of the NiB₇₁N₇₂ clusters occurs to embed the NH₃ molecules. The NH₃ molecules prefer to adsorb on rather than embed into the NiB_m−1N_m clusters. The charge transfer between the NH₃ molecules and the NiB_m−1N_m clusters is limit, in the range of 0.002–0.221 |e|. The adsorption between the NH₃ molecules and the NiB_m−1N_m clusters is chemical process. In a word, the curvature effects of the Ni-doped boron nitride nanotubes with various diameters on NH₃ adsorption are restrict.

In this work, we designed and synthesized two novel bi-heteroatom functionalized hyper-crosslinked porous polymers (HCP-CT and HCP-CF) through a simple one-step Friedel–Crafts alkylation reaction. The resulted polymers N/S bi-heteroatom functionalized polymer HCP-CT and N/O bi-heteroatom functionalized polymer HCP-CF both have good adsorption property for organic dyes such as methyl orange (MO) and methylene blue (MB) in aqueous solution due to its rich pore structure, high specific surface area and rich-heteroatoms of pore surface. It is worth mentioned that the maximum adsorption capacity (q_max) of cationic dye MB by the porous polymer HCP-CT at room temperature was reached up to 1571.46 mg/g, which is much higher than that of most reported porous materials. Furthermore, the adsorption capacity of HCP-CT for the cationic dye MB was more than seven times that of the anionic dye MO (q_max = 212.77 mg/g). Also, the polymer HCP-CF for the MB adsorption capacity (q_max = 352.11 mg/g) was more than twice higher than that of anionic dye MO (q_max = 131.75 mg/g). The above trends may be because of the stronger electrostatic interaction between the negatively charged N-S/O bi-heteroatom of HCP-CT and HCP-CF with the cationic dye MB than that of MO. In addition, the removal percentage of polymers HCP-CT and HCP-CF still remained above 80% after five adsorption–desorption cycles. Hence, this work may provide a convenient synthetic route to develop a novel hyper-crosslinked polymer with high capacity for the entrapment of dyes from aqueous solution.

We have developed a one-pot, four-component synthetic approach utilizing 5-sulfosalicylic acid dihydrate (5-SSA.2H₂O) as an organocatalyst, enabling the synthesis of polyfunctional 3-pyrrolin-2-one molecules by employing dialkylacetylenedicarboxylate, amines, and either formaldehyde or aromatic aldehydes at room temperature. This approach presents numerous notable benefits such as shorter reaction time, simple and eco-friendly procedure, excellent yield, broad applicability across various substrates, and the use of a cost-effective, easily accessible and biodegradable catalyst. The structures of the 3-pyrrolin-2-one molecules were confirmed using techniques such as FTIR, ¹HNMR, ¹³CNMR and HRMS. Overall, this study demonstrates a promising method for producing environmentally friendly polyfunctional 3-pyrrolin-2-one efficiently and smoothly at ambient temperature.

Herein, Cu₂O–CuO incorporated oxygen-doped g-C₃N₄ has been utilized for the colorimetric sensing of H₂O₂ by the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB). The material characterization studies via XPS, XRD, FTIR spectroscopy etc. proved the presence of both Cu₂O and CuO as well as the doping of oxygen on g-C₃N₄. The use of citric acid in the preparation led to a mesoporous architecture together with oxygen doping to g-C₃N₄. The high peroxidase-like activity of the present Cu-incorporated exfoliated g-C₃N₄ nanoenzyme aroused from the improved features such as smaller band gap, porous nature, oxygen doping to g-C₃N₄, and thus resulted fast electron mobility and transfer. Michaelis–Menten mechanism is used to study the kinetics, where the obtained K_m and V_max values are found to be relevant in comparison with the reported studies. From the mechanistic investigation, the reactive oxygen species involved in the TMB oxidation is ascertained as oxygen superoxide radical anion (^•O₂⁻). The linear range in sensing is 2.5–250 µM with a limit of detection (LOD) of 1 µM H₂O₂. The nanoenzyme showed the least amount of interference and a promising reusability in H₂O₂ sensing.

Graphical abstract

MoS₂ stands out as a distinctive material, owing to its two-dimensional structure, with promising potential across various domains notably in energy storage and photocatalysis. In the present work, a pH-assisted hydrothermal approach (one step) has been utilized to synthesize MoS₂ nanoflowers (NFs) using ammonium molybdate and thiourea. Characterization of the prepared MoS₂ NFs was conducted using XRD, FESEM, HRTEM, FTIR, Raman, UV–Vis, PL, BET and XPS techniques. XRD analysis reveals the hexagonal structure of the prepared NFs, while SEM & TEM images confirm the flower-like morphology consisting of many thin petals. Band gap energy determined through the absorption spectrum is 1.9 eV. Notably, the PL spectrum exhibits a strong and broad peak at 688 nm attributed to band-to-band transition indicating multilayer formation of MoS₂ NFs, which is further confirmed by Raman spectroscopy. XPS also confirms the formation of MoS₂ showing Mo⁺⁴ and S⁻² valance states. The specific surface area of MoS₂ NFs is found to be 108.446 m² g⁻¹ that is very high compared to similar materials. Electrochemical properties of MoS₂ NFs were also investigated showing a specific capacitance of 761 F g⁻¹ at 4 A g⁻¹ with an energy density of 21 Wh kg⁻¹ and a power density of 886 Wkg⁻¹ for the MoS₂ NFs-based electrode. Moreover, photocatalytic degradation of MB using MoS₂ NFs at different weight contents (10, 15, 20 and 25 mg) was explored demonstrating highest 97% degradation of MB within 90 min with 20 mg photocatalyst loading along with 0.04 min⁻¹ reaction rate. It also shows good reusability for four consecutive cycles. Furthermore, photodegradation mechanism has also been explored.

In the field of electrochemical ozone production, electrodes need to have exceptional catalytic activity, long-term stability, and cost-effectiveness. In this case, TiO2-NTs/SnO₂-Sb₂O₅-NiO electrodes were fabricated using a combination of anodization, electrochemical deposition, spin coating and annealing techniques. The coating of electrodes was analyzed using EDS, XRD and SEM techniques. According to the obtained cyclic voltammetry (CV) data, the TiO2-NTs/SnO₂-Sb₂O₅-NiO electrode revealed a less positive potential for oxygen evolution compared to other constructed electrodes. The conversion of Ti to Ti-NTs improved the ozone production efficiency and resulted in higher concentrations of water-soluble ozone. To evaluate the performance of the electrodes and the corresponding electrocatalytic activity, a textile dye was used as a pollutant. The most effective modified electrode proved to have an impressive decomposition rate of 96% for the cationic yellow 28 dye within a 60-min timeframe. Furthermore, this modified electrode could substantially remove chemical oxygen demand (COD) of up to 53.6% during 60-min electrolysis.