نتایج جستجو برای: solid catalyst
تعداد نتایج: 230752 فیلتر نتایج به سال:
The applications of molecular surface chemistry in heterogeneous catalyst technology, semiconductor-based technology, medical technology, anticorrosion and lubricant technology, and nanotechnology are highlighted in this perspective. The evolution of surface chemistry at the molecular level is reviewed, and the key roles of surface instrumentation developments for in situ studies of the gas-sol...
polyethylene glycol was easily grafted to silica gel and used as a solid–liquid phase transfer catalyst in the reduction of aromatic nitro compounds. this silica-grafted polyethylene glycol is proved to be an efficient heterogeneous catalyst in the reduction of nitroarenes to the corresponding aromatic amines with zinc powder in water. the reduction reactions proceeded efficiently with excellen...
An environmentally benign green protocol for the synthesis of 5-unsubstituted 3,4-dihydropyrimidin-2(1H)-ones using Amberlyst 15 DRY as a recyclable catalyst has been developed. The use of resinous, nontoxic, thermally stable, and inexpensive Amberlyst 15 DRY, as a recyclable heterogeneous catalyst, makes the process simple with negligible chemical waste. Among the various solid acid catalysts ...
Solid-state NMR and DFT calculation studies certified the presence of an intermolecular solvent effect for molecules confined in microporous zeolite, leading to a notable increase in Brønsted acidity of the solid acid catalyst.
A simple procedure afforded novel spiroacenaphthylene derivatives in high yields at room temperature from acenaphthenequinone, malononitrile, and phenol derivatives using amino-functionalized silica (SBA-Pr-NH2) as a heterogeneous efficient solid base catalyst. Using SBA-Pr-NH2 in the current procedure presents several advantages, such as a simpler procedure, shorter reaction times, facile synt...
We study the restructuring of solid nickel catalyst nanoparticles during carbon nanotube growth by environmental transmission electron microscopy and multiscale modeling. Our molecular dynamics/continuum transport calculations of surface-diffusion-mediated restructuring are in quantitative agreement with the experimentally observed catalyst shape evolutions. The restructuring time scale is dete...
In this research study, methanol synthesis catalysts were manufactured with various mole ratios of metal carbonates (zinc, copper and aluminum carbonate) and ammonium hydrogen carbonate via a green solid-state method that employed a ball mill apparatus. Some parameters for the catalyst preparation, such as Al mole percent, Cu/Zn mole ratio, rotations milling speeds and aging time, were optimize...
nano sulfated titania was tested as solid acid heterogeneous catalyst for the synthesis of 4-(trifluoromethyl) coumarin and coumarin derivatives under solvent-free condition. factorial design evidenced a positive effect of reaction temperature, amount of catalyst, and solvents. this nano-sized sulfated titania has been prepared by a sol-gel hydrothermal process. the prepared sulfated titania s...
3,4-ِdihydropyrano[c]chromene derivatives were synthesized using sulfonic acid functionalized silica (sio2-pr-so3h) as a highly efficient heterogenous solid acid catalyst via one-pot three-component condensation of aromatic aldehydes with malononitrile and 4-hydroxycoumarin in excellent yields.
Ammonium monovanadate (NH4VO3) has been devoted as an efficient, commercially available, eco-friendly and reusable catalyst for the synthesis of bis(indolyl)methanes (BIMs), oxindole derivatives and also Michael adducts of indoles at 50 °C under solvent-free conditions. The reusability of this solid acid catalyst in addition with its selectivity has also been examined.
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