Research on Chemical Intermediates最新文献

Olefin is a crucial chemical intermediate that is in high demand for polymer production. The catalytic alkyne semi-hydrogenation process represents a promising avenue for industrial purification of olefins. Herein, we report the findings of a study investigating the transfer of alkyne semi-hydrogenation over a bimetallic catalyst, in which Pd nanoparticles and highly dispersed Ni atoms were anchored onto graphite-like C₃N₄ with nitrogen defects. The optimal Pd_0.14Ni_0.01 catalyst was used for intermolecular semi-hydrogenation of alkynes in conjunction with sodium borohydride. Nitrogen defects heightened the catalytic activity by modifying the electron density distribution and accelerating charge transfer from Pd to C₃N₄. Furthermore, the synergism of the Pd–Ni bimetallic positions facilitated the generation of the intermediate styrene and accelerated the rate-determining step. This study provides novel insights into the design of streamlined high-performance semi-hydrogenated catalysts.

In recent inclination, waste-derived catalytic materials have gained a unique identity in the catalytic community due to their versatile properties. These catalytic systems can play a prominent role in the sustainable synthesis of functionalized heterocycles, as they are inexpensive alternatives while being an efficient, user-friendly material. The current review examines the preparation and applicability of waste-derived catalysts in heterocycle synthesis including Michael addition, Knoevenagel condensation, dehydrogenation, oxidation, oxidative dehydrogenation, and others. Moreover, the challenges, possible future development directions, and opportunities in synthesizing potent bioactive heterocycles over waste-derived catalytic materials are addressed. This review will galvanize further research to explore advanced catalysts developed from waste materials and their implications in heterocyclization.

Calcium hydroxide (Ca(OH)₂) is an inexpensive, widely available desulfurization absorbent with limited calcium utilization in dry flue gas desulfurization. To improve the desulfurization performance of Ca(OH)₂, this study provides a simple and industrially applicable method for modifying Ca(OH)₂ using surfactants. Three surfactants, triethanolamine (TEA), diethylene glycol (DEG), and propylene glycol (PPG), were selected from ten surfactants for modifying Ca(OH)₂. The surfactants were added at mass fractions of 2 wt%, 4 wt%, 6 wt%, 8 wt%, and 10 wt%. The addition of 6 wt% TEA synthesized a Ca(OH)₂ with a specific surface area of 52.59 m²/g and a pore volume of 1.88 cm³/g. The desulfurization test was conducted in a fixed bed reactor at an SO₂ concentration of 800 mg/m³, a reaction temperature of 100 °C, an O₂ concentration of 12%, and a water vapor content of 9%. The high specific surface area Ca(OH)₂ exhibited a breakthrough time of 60 min and a SO₂ adsorption capacity of 84.43 mg/g, more than 4 times that of ordinary Ca(OH)₂. The physicochemical structural changes of high specific surface area Ca(OH)₂ before and after the reaction were characterized using Brunauer–Emmett–Teller (BET) analysis, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetry analysis (TGA), scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS), and the reaction mechanism was analyzed. The results indicated that adding TEA changed the crystal structure and surface morphology of Ca(OH)₂. The Gibbs free energy, surface energy, and polarity of the surfactants affected the quicklime digestion, causing a complexation reaction between Ca²⁺ and TEA, altering the surface structure of Ca(OH)₂.

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In an attempt to devise an effective catalyst for 5-hydroxymethylfurfural production, zirconia sulfate was prepared through a facile protocol and immobilized on graphitic carbon nitride nanoplate. The catalyst was analyzed via various techniques, encompassing FTIR, XRD, BET, SEM/EDS, XPS, ICP, and mapping and utilized as a heterogeneous catalyst for the dehydration of fructose to 5-hydroxymethylfurfural. Optimization of the reaction conditions using the response surface method revealed that 40 wt% of the catalyst at 80 °C resulted in 98% product in 40 min. Gratifyingly, the catalyst showed high recyclability up to 7 runs with scant leaching of zirconia sulfate. A comparative study also underlined that a combination of zirconia sulfate and graphitic carbon nitride nanoplate was beneficiary for catalysis and resulted in an improvement of the catalytic activity. The kinetic assessments also indicated that E_a was 23.74 kJ/mol. Moreover, the thermodynamic parameters of ({Delta text{H}}^{ne }), ({Delta text{S}}^{ne }) and ({Delta text{G}}^{ne }) were determined as 19.35 kJ/mol, − 0.17 kJ/mol and 79.36 kJ/mol, respectively.

Oxidase-mimicking nanozymes are more desirable for applications than peroxidase-mimicking ones owing to H₂O₂ can be omitted. In this work, a facile strategy was reported to prepare a series of Co-based bimetallic oxide nanosheets (Co–M–O NSs, M = Fe, Ni, Mn) derived from different isomorphism precursors. Herein, a comprehensive and systematic research of oxidase-like enzymes based on distinctions of elemental surface content and surface state has been undertaken. The porous Co–Mn–O NSs made of Mn-doping Co₃O₄ can lead to decrease the size of Co₃O₄ nanoparticle from 20–50 to 20–30 nm, and increase in oxygen vacancy from 20.7% to 21.8%. The Co–Mn–O NSs via the Mn-doping could highly enhanced the performance and efficiency of the oxidase-mimicking, which is 7.5 times than that of Co₃O₄ and other elements (Ni, Fe) doping Co₃O₄. Considering the features of Co–Mn–O NSs, a sensitive and selective colorimetric assay for the detection of L-cysteine (L-cys) was established. The system showed a linear absorbance response to L-cys concentrations ranging from 0.8 to 70 μM, with a detection limit of 0.79 μM. This facile and effective fabrication strategy of Co–Mn–O NSs has discovered a highly efficient oxidase-mimicking nanozyme useful in environmental protection, biotechnology, and clinical diagnosis.

Sulphur (S) doping in kesterite CZTSe has been performed via a hydrothermal method. X-ray diffraction (XRD) study indicated the particles have grown in a tetragonal phase and the shift towards higher two theta values upon S doping confirmed the formation of Cu₂ZnSn(SSe)₄ (CZTSSe) alloy. Raman analysis corroborated the XRD results, ruling out the possible presence of secondary phases. Polygonal-shaped nanoparticles of varying dimensions are formed, agglomerated as cauliflower-like structures (scanning electron microscopy). The transmission electron microscopic (TEM) images provided enhanced view about the morphology revealing 2D nature of the nanopolygons. Average particle dimensions of CZTSe particles are ~ 20 nm and that of CZTSSe are ~ 15 nm. Both CZTSe (E_g ~ 1.2 eV) and CZTSSe (E_g ~ 1.45 eV) are visible light active, with CZTSSe nanoparticles band gap blue shifted. CZTSSe photodegraded 98% methylene blue (MB) and 80% methyl orange (MO) under visible light illumination in just 120 min. The use of a convex lens enhanced the catalysts activity, degrading whole of MB dye in just 90 min. The active species corresponding to the photocatalysts are superoxide free radicals which were confirmed by the scavenger test. High efficiency, better rate constant values together with good stability and reusability make the photocatalysts prospective material for futuristic environmental remediation.

We report a new series of isatin-oxime-based Schiff base derivatives (p–H, p–Cl, p–CH₃). Structural analyses of the compounds were conducted through FTIR, ¹H NMR, UV–Vis, and elemental analyses. X-ray crystallography demonstrated that compounds 1 and 2 adopted an orthorhombic crystal system with a P bca space group. Hirshfeld surface (HS) analysis indicated that hydrogen bonding and van der Waals interactions were predominant in the crystal packing. The volumes of the crystal voids and the percentages of free spaces in the unit cells were calculated as 293.87 ų and 10.63% (for 1), 320.34 ų and 11.04% (for 2), respectively. The evaluations of energy frameworks showed that stabilization was dominated by electrostatic energy contributions in compounds. In silico investigations on the DNA binding activity showed that the binding activity of the compounds was mediated via intercalation. The anticancer activity of the compounds was also tested via an MTT assay using HepG2 (liver cancer), Caco-2 (colorectal adenocarcinoma), A549 (lung cancer) and HEK-293 (normal cell) cell lines. The MTT assay demonstrated significant cytotoxic activity of compound 1 across HepG2, Caco-2, A549, and HEK-293 cell lines, with IC₅₀ values of 5.07 µM, 5.19 µM, 4.01 µM, and 5.63 µM, respectively, after 24 h, surpassing cisplatin in efficacy at all tested time intervals. The data indicate that substituents play a significant role in modulating cytotoxicity, with compound 1 (p–H) demonstrating the highest activity. These findings demonstrate the high cytotoxicity and cancer cell selectivity of isatin-oxime-based Schiff base derivatives, especially compound 1, suggesting their potential as strong alternatives to traditional chemotherapy agents.

In the present study, a versatile biomaterial of chitosan polymer/ginger (Zingiber officinale Roscoe) extract/ZnO bionanocomposite (CS/GE/ZnO) was formulated. The physicochemical characteristics of the CS/GE/ZnO were examined using a variety of techniques, including Brunauer–Emmett–Teller (BET), elemental analysis (CHN), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectrum (FTIR), and field emission scanning electron microscopy (FESEM). The elemental analysis indicated that CS/GE/ZnO comprised 22.82% carbon, 4.17% hydrogen, 2.32% nitrogen, and 70.69% oxygen. The BET analysis indicated that CS/GE/ZnO possesses a specific surface area of 11.41 m²/g and a total pore volume of 0.0596 cm³/g. The CS/GE/ZnO exhibits a mesoporous structure with a mean pore diameter (20.91 nm). By analyzing the cytotoxicity and antioxidant properties of the CS/GE/ZnO biomaterial on a breast cancer cell line (MDA-MB-231), its biological activity was determined. In contrast to the standard ascorbic acid (78.08%), the CS/GE/ZnO biomaterial demonstrated an exceptional DPPH radical scavenging efficiency of 78.66%. An IC50 value of 103 μg/mL was determined through MTT assay research on breast cancer investigations involving CS/GE/ZnO and the MDA-MB-231 cell line. The CS/GE/ZnO biomaterial demonstrates efficacy as a chemotherapeutic agent against breast cancer cells, as evidenced by the results. The performance and structure of the CS/GE/ZnO biomaterial indicate potential advancements in nanomaterials for biomedical applications.

The application of diesel, which is a key energy source, in cold climates is limited by its poor low-temperature flowability. Addressing this critical issue, this study designed and synthesized a series of novel comb shaped pour point depressants. This work showed how to synthesize and characterize three innovative copolymers: binary systems comprising tetradecyl methacrylate (C₁₄MC) with either dioctyl maleate (DOM) or vinyl benzoate (VB), and C₁₄MC-DOM, C₁₄MC-VB and C₁₄MC-DOM-VB were synthesized by integrating the three structural units mentioned above. The outcomes of the experiment show that adding the ternary copolymers(C₁₄MC-DOM-VB), particularly with a molar composition of 15:1:1 and the addition amount of 2000 ppm, improves the cold flow characteristics of diesel significantly, as shown by a decrease of 21 °C in solidification point and 12 °C in cold filter plugging point, respectively. Mechanistic investigations suggest that the comb-like structure and inclusion of benzene rings within the ternary copolymers furnish a multitude of nucleation sites, thereby more effectively disrupting the formation of extensive wax crystals. These mechanistic insights are substantiated by an array of analytical techniques, including rheologic analysis, differential scanning calorimetry and polarizing optical microscopy.

In this study, zinc vanadate nanocomposite (ZVNC-Zn₃V₂O₈) was prepared by hydrothermal method. SEM, UV–visible spectroscopy, PXRD, and TEM were utilized to analyze the morphology, crystal structure, particle size, and optical properties of the nanocomposite. The average crystallite size of synthesized nanocomposite was deducted ~ 24.48 nm. The measured energy bandgap was 3.4 eV, making the material suitable for degradation studies under ultraviolet (UV) light exposure. Notably, the degradation efficiency for malachite blue and malachite green was 87.15% and 92.64%, respectively. Additionally, the same compound was utilized for the detection of ascorbic acid, and charge–discharge studies revealed extremely low R_Ct and C_dl values of 82.4 C and 0.000125 F, respectively. These findings indicate that the charge transfer process in ZVNC is highly efficient, enabling rapid and effective energy transmission. These properties suggest that ZVNC hold significant potential for applications in energy and environmental fields, offering valuable insights into their material characteristics.

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