Research on Chemical Intermediates最新文献

A novel drug delivery system based on amorphous zeolite derived from kanemite for doxorubicin (Dox) has been constructed. Structural analysis indicated that the initial Na-Ka was an orthorhombic structure with lattice parameters of a = 7.267(9)Å, b = 21.03(3)Å, and c = 4.878(8)Å. After protonation of Na-Ka by HCl solution, the resulting H-Ka was an zeolite with orthorhombic structure, and its lattice parameters are a = 7.45(2)Å, b = 11.85(5)Å, and c = 4.905(9)Å. Then the H-Ka was reacted with tetra-n-butyl ammonium hydroxide (TBAOH) solution, yielding Ka-TBA colloid suspension, and the Ka-TBA sediment exhibited amorphous state. While the Ka-TBA colloid suspension was reacted with doxorubicin (Dox) hydrochloride solution by ion exchange, the yielded Ka-Dox was amorphous. Composition analyses revealed that the chemical formula of Na-Ka, H-Ka, and Ka-Dox was estimated to be NaHSi₂O₄(OH)₂·2.0H₂O, H₂Si₂O₅·0.72H₂O, and H_1.82(C₂₇H₃₀NO₁₁)_0.18·Si₂O₄(OH)₂·1.31H₂O, respectively. The loading capacity of Ka-Dox for Dox was about 35.24%. Drug release suggested that the Ka-Dox exhibited extremely slow and sustained release of drug in phosphate buffer solution (PBS, pH = 7.4), and the drug release percentages were 2.42%, 2.84%, 3.12%, and 3.40% after 24 h, 48 h, 72 h, and 96 h, respectively. This extremely slow and sustained release of drug may be potential application in the medical field, such as maintaining stable blood drug concentrations over prolonged periods, improving the compliance and safety of drug treatment, and reducing the toxic side effects.

This study highlights the design of a novel organo-nanocatalyst by grafting of thiourea onto dendritic fibrous nanosilica (DFNS). The resulting catalyst, named KCC-1-nPr-thiourea, was characterized using advanced techniques, such as FE-SEM, TEM, FT-IR, EDAX, mapping analysis. Also, pore size, pore volume and surface area of KCC-1-nPr-thiourea was determined by BET-BJH adsorption/desorption method which were 14.44 nm, 0.36 cm³/g and 100 m²/g, respectively. The analysis revealed that the catalyst exhibits uniform spherical morphologies with a fibrous dendritic structure. The fabricated nanocatalyst (KCC-1-nPr-thiourea) demonstrates outstanding performance due to its unique dendritic structure, which greatly enhances the accessibility of its active sites. KCC-1-nPr-thiourea as an advanced heterogeneous nanocatalyst, enhance the efficiency of 1,8-dioxo decahydroacridine synthesis through a one-pot, four-component reaction involving aromatic aldehydes, dimedone, and ammonium acetate, under solvent-free conditions. Its specialized structure optimizes the dispersion and adsorption of reactants and products within its pores and channels, contributing to its effectiveness in catalysis. This innovative approach dramatically reduces reaction times to just 10–20 min, yielding impressive product outputs of 93–98%, outperforming previously documented methods. With its multifunctional nature and environmentally friendly design, this organo-nanocatalyst offers a highly efficient and sustainable platform for producing diverse organic compounds. The porosity, high surface area and stability of silica nanoparticles as a support enhances the catalytic activity, recoverability and reusability of thiourea functional group.

The environmental pollution caused by organic dye wastewater presents a significant threat to human health. Photocatalysis has emerged as a promising approach for addressing wastewater contamination. In this study, a novel synthesis strategy was developed using the MOF-5 template method. By precisely regulating the amount of Bi³⁺ ions introduced into the MOF-5 precursor and employing controlled calcination, Bi-doped ZnO nanomaterials were successfully synthesized. XRD, SEM, TEM, and XPS analyses demonstrated that a 4% Bi doping level resulted in uniform incorporation of Bi into the ZnO crystal lattice, inducing local coordination modifications. EPR results indicated that the surface oxygen vacancy density of Bi–ZnO (4%) was higher than that of pure ZnO, which contributed to enhanced photocatalytic performance. UV degradation experiments revealed that at a Bi content of 4%, the degradation efficiency of methyl orange reached a maximum of 92%, significantly surpassing the 57.5% efficiency observed for pristine ZnO. Furthermore, cycling experiments confirmed the excellent stability of the catalyst. Reaction mechanism investigations indicated that photogenerated holes (h⁺) played a dominant role in the degradation of methyl orange by Bi–ZnO. Density functional theory (DFT) calculations indicate that bismuth doping renders the material metallic, thereby facilitating the efficient separation of photogenerated charge carriers. Under light irradiation, these doping-induced holes facilitated the formation of a space charge layer, thus facilitating the effective separation of photoinduced electron–hole pairs.

This study investigated the use of commercial chitosan as a simple, eco-friendly, and efficient organocatalyst for the synthesis of xanthene and tetraketone derivatives via a cascade reaction. The reaction between various salicylaldehydes and dimedone (1:2 molar ratio), conducted in water at 75 °C, and catalyzed by chitosan, produced xanthene derivatives (3a–g) in good to excellent isolated yields (73–93%) within short reaction times (10–60 min). When benzaldehyde was employed as the aldehyde component, tetraketone derivatives (5a–g) were formed instead of xanthene derivatives. A series of substituted benzaldehydes were also investigated, efficiently affording the corresponding Tetraketone derivatives in high yields (82–94%) and short reaction times (10–20 min). The reusability of chitosan was confirmed, with no significant decrease in catalytic activity or structural integrity after six consecutive cycles. The synthesized compounds were evaluated for their cytotoxic activity against K-562, A-549, and HCT-116 tumor cell lines, as well as the non-tumor cells MRC-5. Xanthene derivatives demonstrated superior activity, particularly compound 3f, which exhibited low IC₅₀ value for HCT-116 (5.54 µM) and SI of 0.54 (SI = IC_{50 (MRC-5)}/IC_{50 (HCT-116)}). These findings indicate the potential of these molecules as anticancer agents, while also highlighting the need for further structural optimization to enhance selectivity, especially against colon cancer cells.

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A microwave-assisted method was developed for rapid synthesis of histidine-functionalized copper nanoclusters (His@CuNCs) as fluorescent probes for vitamin B12 (VB12) detection. This method uses histidine as a stabilizer and ascorbic acid as a reducing agent, enabling single-step green synthesis within 1 min, much faster than traditional methods. The nanomaterial exhibited intense blue–green fluorescence (λem = 466 nm) with quantum yield of 10.38%. Moreover, the His@CuNCs showed exceptional environmental stability, maintaining their optical properties under varying ionic strengths, pH conditions, and prolonged UV exposure. Upon VB12 introduction, specific electron transfer from VB12 to His@CuNCs caused fluorescence quenching via static quenching and IFE mechanisms. The probe demonstrated a linear response from 0.5 to 270 μM with 0.033 μM LOD, outperforming most of existing nanocluster-based sensors. The platform demonstrated practical utility of determination of vitamin B12 in vitamin drink and bovine serum samples, and sensing temperature.

This study depicts the application of fulvic acid (FA) as a biodegradable, reproducible, and efficient catalyst for the synthesis of tetrahydropyrimidine-5-carboxamides (4a–4j) via a one-pot three-component reaction of urea, aldehydes, and 3-oxo-N-(5-phenyl-1,3,4-thiadiazol-2-yl)butanamide, as well as the synthesis of benzo-chromeno-pyrimidin-amines (8a–8l) using a one-pot pseudo-five-component reaction of 1-naphthol, aldehydes, malononitrile and ammonium acetate at mild temperatures in aqueous medium. Green reaction environment, operational simplicity, low catalyst usage (0.02–0.04 g), superb yields (90–98%), short reaction times (15–33 min), presentation of novel derivatives to the literature, and the possibility of easy recovery of the catalyst from the reaction mixture for up to six runs without significant loss in catalytic activity are the salient aspects of the above synthetic routes.

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InGaN is a promising photocatalytic material with excellent and tunable optical properties. However, the effect of modifying InGaN thin films with various modifier layers on photocatalytic CO₂ reduction remains underexplored. In this work, we systematically investigated the impact of g-C₃N₄, TiO₂, and their bilayer combination on the photocatalytic performance of InGaN photoanodes. The simultaneous loading of g-C₃N₄ and TiO₂ onto InGaN yielded the most significant enhancement. This configuration resulted in a CO₂-to-CO conversion rate of 4.725 µmol·mol⁻¹, which is 2.35 times higher than that of bare InGaN (2.006 µmol·mol⁻¹). Furthermore, the production of H₂ and hydrocarbons was also augmented. Electrochemical and spectroscopic analyses revealed that the bilayer structure synergistically combines the high light-harvesting capability of TiO₂ with the improved CO₂ reduction selectivity of g-C₃N₄, while also mitigating photocorrosion. This work demonstrates that constructing hybrid modifier layers is an effective strategy for boosting the activity and stability of InGaN-based photocatalysts for CO₂ reduction.

The efficient and comparative synthesis of bis-enol derivatives using WEPAPA and WEPPA bio-waste catalysts has been reported in the present study. The catalysts were considered to be economical, recyclable and sustainable. During optimum studies, the percentage yield of the product was above 85% in both the cases. However, in the case of WEPPA catalyst, there was a marginal decrease of 4% in the yield. The reaction was susceptible for the formation of a number of derivatives. The products obtained were removed from reaction mixture using simple filtration technique and did not require any column chromatographic techniques for purification. The products obtained were recrystallized using hot ethanol. The products were identified by the use of ¹H and ¹³C NMR spectroscopic techniques. Both the catalysts were recyclable up to four times maintaining their catalytic efficiency throughout the cycles.

Hydrogen is considered a future fuel. However, mostly hydrogen is generated with other gases such as CO, CO₂, N_2, etc. Therefore, the separation of hydrogen from these gases is vital. Palladium-based membranes are commonly used for hydrogen separation. However, preparing a defect-free membrane on porous substrate is still a major challenge. This study highlights the development of appropriate intermediary layers to facilitate uniform palladium deposition on commercially available alumina substrates. CeO₂-YSZ intermediate layers are used on a porous alumina tube before depositing the palladium layer. YSZ and CeO₂ layers are deposited through the vacuum-assisted dip-coating method, and the palladium layer is deposited on the intermediate CeO₂-YSZ layers using the electroless pore plating (ELP-PP) method. The single solution of the Pd is used to prepare the membrane by optimizing the solution's N₂H₄ (0.1 M–0.5 M) concentration. SEM and EDS analyses are carried out to investigate the membrane surface morphology and pore size distribution, focusing on understanding the intermediate layer's effect. The permeation property of the membrane is tested at different temperatures (300–400 ℃) and pressure ranges (0.5–3.0 bar). The membrane testing is performed with pure hydrogen and hydrogen and nitrogen mixture of different compositions. At 400 °C, the membrane permeability was 3.3 × 10^–6 mol s⁻¹ m⁻² Pa⁻¹ at 1 bar, which is one of the highest reported values compared with the literature. The nitrogen is retained completely, ensuring the hydrogen's high purity.

Cubic nickel oxide (NiO) embedded with graphitic carbon nitride (g-C₃N₄) nanocomposite, NiO@g-C₃N₄, serves an effective photocatalyst to the degradation of synthetic blue food dye, Indigo Carmine (IC). The nanocomposite was prepared using a facile thermal polymerization technique followed by an annealing procedure. The as-synthesized nanocomposite’s structures and morphologies were characterized using different techniques. The efficiency of degradation and reaction kinetics were evaluated using UV–visible spectroscopy under sunlight exposure. The catalyst’s degradation rate for IC dye was approximately 99.34% achieved in 19 min under an optimal reaction conditions. The degradation rate was followed a pseudo-first order kinetics of rate constant, k₁ = 196.6 × 10^–3. Other factors such as catalyst dosage, pH of the medium and degradation in tap water were also performed where the efficiency of NiO@g-C₃N₄ have been significantly influenced during the photodegradation process. The impact of coexisting anions and cations on the photodegradation efficiency of NiO@C₃N₄ was additionally evaluated. Trapping agents are introduced to identify the reactive species, and results showed that the super oxide (O₂^.−) radicals are the main reactive species, whereas ^.OH, electrons, and h⁺ holes had a lesser impact on the degradation process. The degradation efficiency of the catalyst in tap water reaches up to 86%. The stability of the nanocomposite was examined through three consecutive catalytic cycles, demonstrating the robustness of the catalyst.