نتایج جستجو برای: sio2 supported silyl chromate catalyst
تعداد نتایج: 249311 فیلتر نتایج به سال:
The (n,m) population distribution of single-walled carbon nanotubes obtained on supported CoMo catalysts has been determined by photoluminescence and optical absorption. It has been found that the (n,m) distribution can be controlled by varying the gaseous feed composition, the reaction temperature, and the type of catalyst support used. When using CO as a feed over CoMo/SiO2 catalysts, increas...
A highly enantioselective acylation of silyl ketene acetals with acyl fluorides has been developed to generate useful α,α-disubstituted butyrolactone products. This transformation is promoted by a new thiourea catalyst and 4-pyrrolidinopyridine and represents the first example of enantioselective thiourea anion-binding catalysis with fluoride.
In this paper, a multifunctional Fe3O4@SiO2@PEI-Au/Ag@PDA nanocomposite catalyst with highly stabilized reactivity and magnetic recyclability was synthesized by a self-assembled method. The magnetic Fe3O4 nanoparticles were coated with a thin layer of the SiO2 to obtain a negatively charged surface. Then positively charged poly(ethyleneimine) polymer (PEI) was self-assembled onto the Fe3O4@SiO2...
The selective reduction of CO2 to the formaldehyde level remains an important challenge and to date only a few catalysts have been developed for this reaction. Herein, we report an efficient catalyst that consists of a bis(phosphino)boryl nickel hydride complex in combination with B(C6F5)3, for the highly selective hydrosilation of CO2 to bis(silyl)acetal derivatives.
A tunable and highly regio- and diastereoselective addition of acyclic silyl dienolates 2 to several α-fluoroalkyl sulfinylimines 1 was developed. By appropriate choice of the Lewis acid catalyst, two new chiral α-fluoroalkyl amines 3 and 4 were obtained in good yields and excellent diastereoselectivities (up to >99 : 1 dr), respectively.
Propylene is an important raw material for the production of many valuable compounds, especially polypropylene, consumption which continues to grow every year. The reaction oxidative dehydrogenation propane, where carbon dioxide used as a mild oxidant, promising method producing propylene. At same time, problem utilization greenhouse gas CO2 partially solved. synthesis and analysis physicochemi...
We report an enantioselective approach to tertiary α-chloro esters through the reaction of silyl ketene acetals and N-chlorosuccinimide. The reaction is promoted by a chiral squaramide catalyst, which is proposed to engage both reagents exclusively through non-covalent interactions. Application of the tertiary chloride products in stereospecific substitution reactions is demonstrated.
Ru(3)(CO)(12)/EtI has been found to be an efficient catalyst system for the dehydrosilylation of carboxylic acids with silanes. In the presence of 1 mol% Ru(3)(CO)(12) and 4 mol% EtI, dehydrosilylation reactions in toluene afforded the corresponding silyl esters at 100 degrees C in good and high yields.
Expanded multilayered vermiculite (VMT) was successfully used as catalyst support and Ni/VMT synthesized by microwave irradiation assisted synthesis (MIAS) exhibited excellent performance in our previous work. We also developed a two-dimensional porous SiO2 nanomesh (2D VMT-SiO2) by mixed-acid etching of VMT. Compared with three-dimensional (3D) MCM-41, 2D VMT-SiO2 as a catalyst support provide...
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