نتایج جستجو برای: magnetic heterogeneous nanocatalyst
تعداد نتایج: 462271 فیلتر نتایج به سال:
In the present study, we carried out chemical synthesis and characterization of Fe3O4@PEG-Au as a magnetic nanocomposite in aqueous solution by chemical co-precipitation of Fe3+ and Fe2+ ions and encapsulated by poly (ethylene glycol) (PEG) in order to enhancing hydrophilicity, biocompatibility and immobilizing gold ions in the presence of NaBH4 as a reducing agent. Nanostructures were characte...
The kinetic of the transesterification reaction over the Cs(x)H(₃-x)PW₁₂O₄₀/Fe-SiO₂ catalyst prepared using sol-gel and impregnation procedures was investigated in different operational conditions. Experimental conditions were varied as follows: reaction temperature 323-333 K, methanol/oil molar ratio = 12/1, and the reaction time 0-240 min. The H₃PW₁₂O₄₀ heteropolyacid has recently attracted s...
The dynamic evolution of nanocatalyst particle shape and carbon composition during the initial stages of single-walled carbon nanotube growth by chemical vapor deposition synthesis is investigated. Classical reactive and ab initio molecular dynamics simulations are used, along with environmental transmission electron microscope video imaging analyses. A clear migration of carbon is detected fro...
An ultra-low Pd loading nanocatalyst is synthesized by a convenient solution route of photochemical reduction and aqueous chemical growth. The modification of nanocatalyst structures is investigated through changing morphologies of Pd nanoclusters on the surface of ZnO nanorods. A significant enhancement in photocatalytic properties has been achieved by decorating a trace amount of Pd clusters ...
N-Propylsulfamic acid supported onto magnetic Fe3O4 nanoparticles (MNPs-PSA) was investigated as an efficient and magnetically recoverable catalyst for the one-pot synthesis of substituted coumarins from the reaction of coumarin with variety aromatic aldehydes in high to excellent yield at room temperature under solvent-free conditions. The magnetic nanocatalyst can be readily recovered easily ...
Sulfuric acid functionalized magnetic nanocatalyst (SAMNC) has been prepared as an efficientacidic and applied in the one-pot preparation of 2,3-dihydroquinazolin-4 (1H) -one derivatives.This catalyst has been characterized by FT-IR, SEM, and VSM. According to the obtainedresults, including time, yield and recyclability, SAMNC could be considered as an efficient catalystfor organic transformati...
A bioinspired peptide amphiphile nanofiber template for formation of one-dimensional Pd nanostructures is demonstrated. The Pd and peptide nanocatalyst system enabled efficient catalytic activity in Suzuki coupling reactions in water at room temperature. The nanocatalyst system can be easily separated and reused in successive reactions without significant loss in activity and structural integrity.
Suzuki-Miyaura coupling reaction catalyzed by the palladium (Pd)-based nanomaterials is one of the most versatile methods for the preparation of biaryls. However, use of organic solvents as reaction medium causes a big threat to environment due to the generation of toxic byproducts as waste during the work up of these reactions. Therefore, the use of water as reaction media has attracted tremen...
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