Research on Chemical Intermediates最新文献

Viologen-based organic electrochromic materials have been extensively studied due to their excellent electrochromic performance. Nevertheless, the dimerization of the radical cation state will destroy the reversibility of viologens and result in poor stability of the electrochromic device (ECD). Herein, two π-extended viologen derivatives (Spr-MPTT and Sbu-MPTT) are synthesized by inserting a thiazolo[5,4-d]thiazole unit between bipyridine moieties and N-bisubstituted with alkyl sulfonate groups. All-in-one hydrogel ECDs are assembled using Spr-MPTT or Sbu-MPTT and ferrocene modified by a water-soluble group. The Spr-MPTT-based ECD exhibited alternating color change between yellow-green and violet, while the Sbu-MPTT-based ECD displayed alternating color change between yellow-green and purple at 1.0/0 V pulse voltage. The extended conjugation of the viologen chromophore confers these devices with visible-NIR absorption and good cyclic stability. Their optical contrasts at 535 nm are 54.85% and 60.17%, respectively, for Spr-MPTT or Sbu-MPTT based ECD. These results demonstrate their potential application in electrochromic hydrogel smart windows.

Ce-doped WO₃ nanoparticles were fabricated and characterized using powder X-ray diffraction (XRD), Fourier-transform infrared (FTIR), Raman, SEM–EDX, UV–Vis, photoluminescence (PL), dynamic light scattering (DLS), and X-ray photoelectron spectroscopy (XPS) analyses. The results revealed the formation of a highly crystalline monoclinic phase in Ce-doped WO₃ photocatalyst (abbreviated WCC), confirmed by Raman spectroscopy. The bandgap was tuned by increasing the percentage of Ce dopant, where the WCC (1 mol wt% Ce-doped WO₃) photocatalyst sample exhibited the highest photocatalytic activity towards synthetic methylene blue (MB) dye pollutant and biodegradation-resistant tetracycline hydrochloride (TC-HCl) antibiotic. The decomposition efficiency using the WCC photocatalyst against aqueous MB dye and TC-HCl antibiotic reached 95% and 51% after exposure to simulated sunlight irradiation for 180 min, with excellent stability after four recycling runs. The interfacial contact between Ce and WO₃ effectively shortened the charge transfer carrier process, enabling redox reactions to provide the best decomposition efficiency over the investigated pollutants. The photodecomposition rate constant of WCC was 0.017 min⁻¹ for MB dye, which is 3.6-fold higher performance than common literature photocatalysts. The results showed the significance of the environmental impact toxicity assessment by applying the treated water to finger millet plant growth. Based on the research feasibility, the synthesized photocatalyst demonstrated superior decomposition against dyes and antibiotics, making it highly suitable for applications in wastewater treatment. Moreover, the use of degraded water resulted in productive plant growth.

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In this study, a Box–Behnken design was employed to optimize the synthesis of quinoxaline derivatives via the condensation of benzil or furyl with 1,2-diamines using zirconium phosphate (ZrP) as a heterogeneous catalyst and water as a green solvent. The effects of reaction temperature (40–50 °C), catalyst amount (0.02–0.04 g), and stirring time (5–15 min) were investigated. The model exhibited excellent predictive accuracy with an adjusted R² of 0.997, yielding 97.90% quinoxalines under optimal conditions: 0.03 g catalyst, 12 min reaction time, and 45 °C. Catalyst reusability was confirmed for up to five cycles, with a slight decrease in yield (~ 90% after five uses). Kinetic analysis revealed first-order reaction kinetics with an activation energy of 70.34 kJ/mol. Thermodynamic parameters, including ΔS, ΔH, and ΔG, were calculated using the Eyring-Polanyi equation. A sustainability assessment using green metrics, such as atom economy (AE), reaction mass efficiency (RME), and the E-factor, demonstrated the improved environmental profile of the process. This method offers a greener and efficient approach for quinoxaline synthesis, with potential applications in the pharmaceutical and fine chemical industries.

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The present paper contains the preparation of QDs sensitized on TiO₂ thin film as a photoanode for solar cell applications. The photoanode is developed by copper sulfide quantum dots (CuS QDs) on TiO₂ thin films using the successive ionic layer adsorption and reaction (SILAR). CuS QDs act as sensitizer because of its strong visible light absorption. Fabrication process comprises sensitizing CuS QDs on the surface of TiO₂ thin films controlled by 5 and 10 SILAR cycles. XRD study indicates the crystallite size of TiO₂/CuS QDs thin films is 11.6 and 13.7 nm for 5 and 10 cycles (cys), respectively. The outcome of UV-DRS and photoluminescence indicates the enhanced light absorption, reduction in bandgap and suppression of electron–hole pair recombination. The HR-TEM image revealed that the diameter of the TiO₂ is 10 nm and surroundings core-like CuS particles are observed. The TiO₂/CuS QDs (10 cys) configuration showed a better photoelectrochemical efficiency of 2.55% at 30 mW cm⁻² light intensity.

In this research, a novel Fe₃O₄@Ti₃C₂ MXene nanocomposite was prepared by a simple ultrasonic method by combining Ti₃C₂ MXene and Fe₃O₄ nanoparticles, and was used for the remediation of malachite green (MG) dye, as an example of an organic pollutant, from the environment through photocatalytic degradation under visible light irradiation. A wide variety of techniques were used to characterize the synthesized Fe₃O₄@Ti₃C₂ MXene nanohybrid, including X-ray diffraction analysis (XRD), surface area analysis, scanning and transmission electron microscopy (SEM and TEM), and Fourier transform infrared spectroscopy (FTIR) in addition to the optical properties and band gap analysis. The results showed that the Ti₃AlC₂ MAX phase’s Al layer was successfully selectively etched, resulting in the two-dimensional layered Ti₃C₂ MXene (average diameter of 78 nm). Additionally, the results revealed the preparation of the cubic Fe₃O₄ phase (average particle size of 11 nm), which was distributed homogeneously on the Ti₃C₂ MXene surface, as indicated by XRD, SEM, and TEM analysis. Moreover, the Fe₃O₄@Ti₃C₂ MXene nanophotocatalyst exhibits good visible light absorption ability under visible light (> 420 nm) due to its huge surface area, excellent conductivity, and sufficient quantity of active sites, and the accessibility of all elements required for effective photocatalysis. Accordingly, under 300 min of visible light exposure, the Fe₃O₄@Ti₃C₂ MXene nanophotocatalyst successfully photodegraded MG dye more efficiently than the pure MXene with a removal percentage of 95.4% with 0.5 g/L loading. Overall, the current study has shown that the Fe₃O₄@Ti₃C₂ MXene nanophotocatalyst has the potential to be a valuable photocatalyst for exceptionally efficient wastewater treatment applications.

Catalysts are widely used in research and in industrial applications to enable or to accelerate chemical reactions. One application is monopropellant thrusters for space propulsion systems, which use hydrogen peroxide (H₂O₂) as liquid propellant. The decomposition of liquid hydrogen peroxide into water and oxygen gas, which then finally generates the thrust, can be achieved using noble metal catalysts like platinum and iridium. In this study, iridium–platinum alloys were deposited onto ceramic pellets by a controlled magnetron sputtering process with different parameters. Selected parameters result in coated layers featuring an atomic structure of closed- and/or open-shell microstructures. The catalytic performance of these coated pellets was evaluated in laboratory experiments. The reactivity of sputtered iridium–platinum layers for the decomposition of H₂O₂ was found to be significantly higher with respect to layers of pure iridium coatings. This can be explained by the better reactivity of iridium–platinum alloys, combined with the active control of the surface morphology and the microstructure of the alloy coatings.

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This article describes the amalgamated of polyboric acid (PBA) and Aminoethyl-3-Aminopropyltriethoxysilane (AEAPTES) by straightforward extrusion process to produce composite (PBA/AEAPTES). It showed basic nature due to amine functionalities on surface of PBA. The composite is applied for the fabrication of pyran derivatives. These reactions are noteworthy for their large product yields, environmental friendliness, quick reaction times, wide range of substrates and no need of hazardous solvents. Moreover, there is no discernible decrease in activity after four reuses of the catalyst and catalyst separated by simple filtration method without any extraction. The resultant composite is characterized by FT-IR, XRD and SEM analysis. In addition, the synthesized compounds characterized by FT-IR, ¹H, & ¹³C NMR analysis.

Here, we highlight an efficient and novel approach for the one-pot multicomponent synthesis of 2-amino-4,6-disubstituted-3-cyanopyridine derivatives through the cyclo-condensation of substituted aromatic aldehydes, ammonium acetate, malononitrile, and aryl ketones under neat conditions. The current protocol offers several key advantages, including short reaction times (approximately 0.55 hours), high yields (up to 96%), mild reaction conditions (80 °C), broad substrate scope, catalyst recyclability, and a simple isolation procedure. The reported method harnesses the catalytic potential of guanidine hydrochloride, serving as a highly effective organo-catalyst, which exhibits exceptional mildness and catalytic activity, facilitating the reaction with high yield. Furthermore, green chemistry metrics such as Eco-Scale (95), E-Factor (0.29), and Process Mass Intensity (1.60) were employed to evaluate the environmental impact of the process.

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New isatin-thiosemicarbazone (1–6) were obtained from various 5-methylisatin and various isothiocyanates with good yields and efficient methods. The structures of the synthesized compounds were clarified by FT-IR, ¹H-NMR, and ¹³C-NMR spectroscopic techniques and elemental analysis. The antioxidant activity properties of the compounds were investigated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method and total reducing power determinations. In our total reducing power study, where we chose Trolox as the standard antioxidant, it was found that the reducing powers of compounds containing different substituent groups and positions were close to each other and lower than Trolox. In the study using butylated hydroxytoluene (BHT) as a reference antioxidant, DPPH antiradical scavenging capacities of the synthesized compounds were determined. The free radical scavenging effects of the synthesized compounds were compared with the IC₅₀ values obtained from the concentration equations and were found in the order BHT > 6 > 3 > 5 > 1 > 2 > 4. Structural and electronic properties of the compounds were examined by density functional theory (DFT) calculations and their relationship with the antioxidant properties of the compounds was discussed. DFT calculations played an important role in determining how the electronic properties of the synthesized compounds, especially in the presence of different substituents and in the ortho and meta positions, and accordingly the antioxidant properties of the compounds, changed. Experimental and theoretical results confirmed that methoxy-containing structures in the synthesized compounds exhibit higher antioxidant effects compared to halogen-containing structures, regardless of their position.

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In recent years, the environmental problems caused by microplastics (MPs) as novel pollutants have received widespread attention, and photocatalytic technology can degrade MPs into small molecule compounds such as aldehydes and ketones. Among the existing catalysts, graphitic phase carbon nitride (g-C₃N₄) shows great potential in degrading pollutants due to its unique properties. In this paper, the structure, preparation method, modification method, mechanism of degradation of MPs and influencing factors of g-C₃N₄ are systematically reviewed. It is summarized that ·OH, h⁺, and ·O₂⁻ are the main active species in the degradation of MPs by g-C₃N₄, and the external conditions such as pH, light intensity, and the morphology of MPs themselves can affect the degradation of MPs. However, g-C₃N₄ photocatalytic degradation of MPs is still only in the laboratory stage at this stage, and problems such as the degradation of MPs in actual water bodies have not been carried out, so how to solve the above problems is the focus of future research in the field of g-C₃N₄ photocatalytic degradation of MPs.