نتایج جستجو برای: supported catalyst
تعداد نتایج: 234324 فیلتر نتایج به سال:
We report the chemo- and regioselective hydrogenolysis of the C-O bonds in di-ortho-substituted diaryl ethers under the catalysis of a supported nickel catalyst. The catalyst comprises heterogeneous nickel particles supported on activated carbon and furnishes arenes and phenols in high yields without hydrogenation. The high thermal stability of the embedded metal particles allows C-O bond cleav...
the use of a recyclable phase transfer catalyst, sio2-peg-imbr, is demonstrated in a simple and highly efficient synthesis of phenacyl derivatives by nucleophilic substitution reaction of phenacyl halides with different anions in water. advantages of this system are easy work-up, moderate to good yields, and recyclable catalyst. the catalyst can be recycled and reused several times with no loss...
Silica sodium carbonate (SSC) has been used as a valuable silica-supported catalyst for the preparation of a range of known and novel pyrano coumarins via the three-component reactions of aryl aldehydes, active methylene compound (malononitrile or ethyl cyanoacetate), and hydroxycoumarin (5,7-dihydroxy-4-substituted coumarins or 4-hydroxycoumarin). The heterogeneous catalyst showed much the sam...
Nano-silica supported boron trifluoride (BF3.SiO2) is an efficient, reusable and eco-friendly catalyst for chemoselective thioacetalization of aldehydes and ketones. So, this catalyst was applied for transthioacetalization of acetals and acylals into their corresponding 1,3-dithiolanes or 1,3-dithianes in good to excellent yields. The reactions were carried out at room temperature under solven...
the commercial profile of the amoco cd mgcl2 supported polypropylene catalyst is presented. the development, the unique method of preparation/production, with emphasis on particle morphology, and the parameters affecting particle size (ps), particle size distribution (psd), and particle shape are discussed in detail. the outstanding performance of the catalyst, tailoredmade for the amoco-chisso...
Poly(4-vinylpyridine)-supported copper iodide nanoparticles is reported as a new, green and recyclable catalyst for the synthesis of aryl-14H-dibenzo [a-o] xanthenes under solvent-free conditions. This catalyst can be recovered by simple filtration and recycled up to 8 consecutive runs without any loss of their efficiency.
Supported olefin polymerization catalysts can prevent reactor-fouling problems and produce uniform polymer particles. Constrained geometry complexes (CGCs) have less sterically hindered active sites than bis-cyclopentadienyl metallocene catalysts. In the literature, micrometer-sized silica particles were used for supporting CGC catalysts, which might have strong mass transfer limitations. This ...
Model catalyst surfaces, consisting of vapordeposited metal nanoparticles supported on a planar oxide support, can help to link reactivity studies on well-defined single crystal surfaces with those conducted on high-surface area supported catalysts. When coupled with near atmospheric pressure kinetic and spectroscopic techniques, these well-defined model catalyst surfaces represent a useful app...
Bimetallic Pt-V supported by Gamma-alumina is used to observe the changes of nheptanewhen passed over this catalyst. The Pt concentration was kept constant at0.1wt% while the concentration of the vanadium was 0.5wt%. The activity andselectivity of catalyst have been determined under conditions at 450-500 degreescentigrade and 15-30 attn. The experimental results show that the addition of second...
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