نتایج جستجو برای: catalyst support
تعداد نتایج: 697984 فیلتر نتایج به سال:
Creating highly active and stable metal catalysts is a persistent goal in the field of heterogeneous catalysis. However, a real catalyst can rarely achieve both of these qualities simultaneously due to limitations in the design of the active site and support. One method to circumvent this problem is to fabricate firmly attached metal species onto the voids of a mesoporous support formed simulta...
Palladium is the best metal catalyst for Suzuki cross coupling reaction for synthesize of unsymmetrical biaryl compounds. But its high cost limits its application in wide scale. Using of nanoscale particles as active catalytic cites is a good approach for reducing needed noble metal. By loading precious nanoparticles on magnetic nanocores as a support, recycling and reusing of catalyst will be ...
The variation of the supports on the Cu/SiO2 catalyst plays an important role in the catalytic performance for hydrogenation of dimethyl oxalate. The loss of silica in the form of tetramethoxysilane from the support under the reaction conditions is responsible for the deactivation of the Cu/SiO2 catalyst.
A simple and efficient Pd/Al2O3-NR-RD catalyst was prepared by depositing palladium on a shape controllable Al2O3-NR support through a two-step process that involves hydrothermal synthesis of Al2O3-NRs followed by reductive-deposition of palladium. This catalyst showed high activity in the catalytic formylation of amines by CO2-H2 under mild conditions with up to 96% yield.
Ca-doped cerium phosphate (CeCaPO(4)) has been newly developed and successfully used as catalyst support with superior ion-exchanged property and oxygen activation ability. Ru(3+) exchanged CeCaPO(4) is identified as an efficient catalyst for aerobic oxidation of alcohols with the highest TOF (∼408 h(-1)) reported so far on supported Ru catalysts.
The design of a new class of triazolium ion precatalysts incorporating protic substituents is described. These materials promote the enantioselective benzoin condensation of a range of aromatic aldehydes (1-62% ee). Catalyst evaluation studies strongly support the involvement of hydrogen bond donation by the catalyst in the stereocentre-forming step of the catalytic cycle.
Catalyst stability in the liquid phase under polar conditions, typically required for the catalytic conversion of renewable platform molecules, is a major concern but has been only sparsely studied. Here, the activity, selectivity, and stability of Ru-based catalysts supported on TiO2, ZrO2, and C in the conversion of levulinic acid (LA) to γ-valerolactone (GVL) has been studied at 30 bar of H2...
nanoporous sodium montmorillonite clay (na+-mmt) was used as a support for the immobilization of 1-methyl-3-(trimethoxysilylpropyl)-imidazolium hydrogen sulfate (na+-mmt-[pmim]hso4). this catalyst showed excellent catalytic activity for the preparation of 2-amino-3-cyano-5-oxo-5,6,7,8-tetrahydro-4h-benzopyrans via three-component reactions between aldehydes, dimedone and malononitrile. the proc...
Polymer-supported chiral 1,2-diamine derivatives have been prepared. The polymers containing free 1,2-diamine moiety were applied to enantioselective hydrogenation catalyst by combination with RuCl2-BINAP complex. Asymmetric hydrogenation of aromatic ketones was performed by means of the polymeric catalyst derived from these polymers to give the chiral secondary alcohols with high ee in quantit...
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