Research on Chemical Intermediates最新文献

In recent years, significant attention has been given to the development of carbon-based adsorbents for the removal of phenol from aqueous environments due to its toxicity and persistence. This review compiles and evaluates 38 such adsorbents, including activated carbon, graphene, graphene oxide, multiwalled carbon nanotubes, and various carbon-based composites, all demonstrating high phenol adsorption capacity. The average uptake capacity was found to be 231.0 mg/g, with adsorbents typically reusable for up to five cycles, an average treatment time of 90 min, and notable activity toward additional pollutants such as dyes, organics, and heavy metals. To aid in practical selection, a guideline was developed based on three primary metrics: (i) uptake capacity (200–700 mg/g), (ii) reusability (4–5 cycles with 80–90% removal efficiency), and (iii) activity for multiple pollutant types. Based on this framework, two activated carbons, derived from Moringa oleifera husk and lignin, emerged as highly effective, with uptake capacities of 612–730 mg/g, reusability over 4–5 cycles, and strong activity toward methylene blue. Similarly, MWCNTs and graphene oxide were also identified as practical adsorbents, with uptake capacities 224–602 mg/g and reusability for up to five cycles, achieving final efficiencies of 80–92%. While the focus is on phenol, the proposed guide is adaptable for identifying adsorbents targeting other contaminants, including pesticides, dyes, and heavy metals. This review contributes a structured evaluation framework that synthesizes key performance indicators; offering a broader, more applicable comparison than typically presented in the literature.

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The present work deals with kinetic study of dihydroxy-1,3-indanedione (Nin) and aspartic acid (AA) in gemini (14-s-14) surfactants at 343 K applying the UV spectrophotometric approach. The values of the rate constant (k_ψ) were determined in geminis by varying different experimental reaction ingredients, i.e., [Nin], [AA], pH and temperatures. The study follows a fractional- and first-order kinetics of paths in [Nin] and [AA], respectively. The effect of several concentrations of gemini surfactants ranging from 1 to 3000 × 10^–5 mol dm⁻³ was carried out and k_ψ achieved at varied concentrations, thus, were recorded. Quantitative analyses of results calculated at [surfactants] are shown as k_ψ vs. [14-s-14] plot and are treated using a kinetic model called pseudo-phase model of micellar catalysis. To evaluate the critical micellar concentration (cmc) of pure gemini and gemini + reactants, a conductometric approach was applied under the current kinetic reaction conditions. Binding parameters (K_X for AA and K_Y for Nin), micellar-rate constant (k_m) and thermodynamic parameters (ΔH^#, ΔS^# and E_a) are also determined and discussed, appropriately.

New isatin-thiosemicarbazone compounds (1–7) were synthesized from numerous thiosemicarbazides and 5-iodoisatin with high yields and efficient methods. The compounds' structures were characterized through FT-IR, ¹H NMR, and ¹³C NMR spectroscopy, supported by elemental analysis. Density functional theory (DFT) calculations were employed to investigate the structural and electronic properties of the compounds, with a discussion on their correlation to antioxidant activity. The antioxidant potential of the synthesized compounds was evaluated in vitro using the 1,1-diphenyl-2-picryl hydrazyl (DPPH^.) free radical scavenging assay. These compounds exhibited IC₅₀ values ranging from 15.36 ± 0.03 to 22.46 ± 0.05 μM, with compound 7 demonstrating the best antioxidant activity among them. The free radical scavenging effects of the compounds, based on their IC₅₀ values, followed the order: 7 > 4 > 6 > 5 > 3 > 2 > 1. Urease inhibition of the samples and their interactions with urease were examined, and it was determined that compound 2 showed the best inhibition effect and interaction as 1.62 ± 0.05 µg/mL and − 7.70 kcal/mol, respectively. Molecular docking was used to ascertain how each molecule interacted with the active areas of the urease enzymes. In addition, molecular dynamics simulation was performed to determine the state of the complex it formed with the enzyme. The current study determined that in vivo biochemical tests of effective thiosemicarbazones could be used to evaluate useful application sectors such as the biological and pharmaceutical fields.

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New thiosemicarbazone derivatives containing 5-iodoisatin have been synthesized, and their structures have been characterized using various spectroscopic techniques. The antioxidant activity of these compounds was assessed using the DPPH^. assay. Additionally, the urease inhibitory effects of the compounds were evaluated, and their interactions with the urease enzyme were studied. Molecular docking studies were conducted to explore how each compound interacts with the active sites of the urease enzyme. Furthermore, molecular dynamics simulations were carried out to investigate the stability and conformation of the enzyme inhibitor complex.

Adequate wastewater treatment is crucial for ensuring access to safe and sanitary water, which can be achieved through photocatalytic processes. This work elucidates the preparation of cost-effective and easily scalable polyacrylonitrile (PAN) electrospun nanofibers (NFs) as support for ZnO nanorods (NRs) photocatalysts. Then, Ag nanoparticles (NPs) were homogenously deposited on ZnO NRs/PAN NFs to prepare Ag NPs/ZnO NRs/PAN NFs samples. Photochemical and electrochemical characterization demonstrated a higher photocurrent density and stability for the Ag NPs/ZnO NRs/PAN NFs than ZnO NRs/PAN NFs. In addition, the prepared photocatalysts were utilized for the photodegradation of various dyes, including methylene blue (MB) and rhodamine B (RhB), as well as tetracycline (TC), an antibiotic serving as a model organic pollutant, under different light illumination conditions. The Ag NPs/ZnO NRs/PAN NFs demonstrated 2.4, 2.6, and 1.6 times higher photocatalytic activity than ZnO NRs/PAN for MB, RhB, and TC photodegradation under UV light, respectively. This floating and free-standing mat, with high stability, demonstrated 82% MB removal after 1 h of exposure to outdoor natural light. Mechanistic studies conducted by adding scavengers revealed that generating hot plasmonic electrons on the Ag NPs through illumination plays a pivotal role in improving the photodegradation activity of Ag NPs/ZnO NRs/PAN NFs mats. Furthermore, ultrasonic vibration was also utilized to induce piezoelectricity in the ternary Ag NPs/ZnO NRs/PAN NFs, resulting in an approximately 2.2-fold improvement in the MB photodegradation rate due to the synergistic effects of piezoelectricity and plasmonics. This durable and reusable photocatalyst, with its mechanical robustness and superior self-cleaning characteristics, is a promising system that offers a potential direction for future research and efficient wastewater treatment.

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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.

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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.