نتایج جستجو برای: magnetic catalysts

تعداد نتایج: 370818  

Journal: :Journal of the American Chemical Society 2015
Xing-Zhong Shu Son C Nguyen Ying He Fadekemi Oba Qiao Zhang Christian Canlas Gabor A Somorjai A Paul Alivisatos F Dean Toste

An efficient method for the synthesis of heterogeneous gold catalysts has been developed. These catalysts were easily assembled from readily available silica materials and gold complexes. The heterogeneous catalysts exhibited superior reactivity in various reactions where protodeauration is the rate-limiting step. Dramatic enhancement in regio- and enantioselectivity was observed when compared ...

2007

● Deactivation of Diesel Catalyst Abstract: The first diesel catalysts, introduced in 1970s for underground mining applications, were simple oxidation catalysts designed for conversion of CO and HC. These catalysts gradually evolved into the modern diesel oxidation catalysts, optimized for PM emission reduction. Future requirements for NOx emission reduction from diesel engines call for new cat...

Journal: :Chemical communications 2014
P K Saini C Romain C K Williams

Some of the most active catalysts for carbon dioxide and epoxide copolymerization are dinuclear metal complexes. Whilst efficient homodinuclear catalysts are known, until now heterodinuclear catalysts remain unreported. Here, a facile, in situ route to a catalyst system comprising a mixture of homo- and heteronuclear Zn-Mg complexes is presented. This catalyst system shows excellent polymerizat...

2000
Makoto Misono Izumi Ono Gaku Koyano Atsushi Aoshima

Basic characteristics of heteropolyacids as green catalysts are overviewed, focusing on the various reaction fields in which the heteropolyacid catalysts function as acid and oxidation catalysts, and then two industrial processes which were made very green by the use of heteropolyacid catalysts in liquid biphase systems are described. In this context an interesting new reaction field formed at ...

Journal: :iranian journal of chemical engineering 0
behrang izadkhah department of applied chemistry and chemical engineering, university of tabriz, tabriz, iran. aligholi niaei department of applied chemistry and chemical engineering, university of tabriz, tabriz, iran. ali tarjomannejad department of applied chemistry and chemical engineering, university of tabriz, tabriz, iran. daryush salari department of applied chemistry and chemical engineering, university of tabriz, tabriz, iran.

in this paper, labo3 perovskite type catalyst formulations were prepared by sol-gel auto combustion method using citric acid as the fuel. activity of catalysts was tested in catalytic oxidation of toluene as a model of volatile organic compounds. lacoo3 perovskite formulation showed the highest activity among labo3 (fe, mn and co) perovskite catalysts. so, lacoo3 perovskite based catalyst was s...

Journal: :Theor. Comput. Sci. 2005
Rudolf Freund Lila Kari Marion Oswald Petr Sosík

The original model of P systems with symbol objects introduced by Păun was shown to be computationally universal, provided that catalysts and priorities of rules are used. By reduction via register machines Sosík and Freund proved that the priorities may be omitted from the model without loss of computational power. Freund, Oswald, and Sosík considered several variants of P systems with catalys...

2011
Gangadhara Raju Padigapati S. Reddy Benjaram M. Reddy

The vapour phase selective conversion of glycerol to acetol at normal atmospheric pressure in a fixed-bed micro reactor was investigated over SO4 2 and WOx promoted ZrO2 and M-ZrO2 (M = Al2O3 or TiO2) solid acid catalysts. The investigated sulfate and tungstate ion promoted zirconia-based catalysts were prepared by both coprecipitation and impregnation methods and calcined at 923 K. The synthes...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2006
Seong H Kim Gabor A Somorjai

This article reviews the surface science of the heterogeneous olefin polymerization catalysts. The specific focus is on how to prepare and characterize stereochemically specific heterogeneous model catalysts for the Ziegler-Natta polymerization. Under clean, ultra-high vacuum conditions, low-energy electron irradiation during the chemical vapor deposition of model Ziegler-Natta catalysts can be...

2011
Yogesh C. Sharma Bhaskar Singh John Korstad

Heterogeneous catalysts are now being tried extensively for biodiesel synthesis. These catalysts are poised to play an important role and are perspective catalysts in future for biodiesel production at industrial level. The review deals with a comprehensive list of these heterogeneous catalysts which has been reported recently. The mechanisms of these catalysts in the transesterification reacti...

2017
M. Matsuoka K. Takahashi H. Yamashita M. Anpo

Cu+l(Si02/A1203), Cu+/A1203 and Cu+/Si02 catalysts were prepared by a combination of the ion-exchange method and thermovacuum treatment. In-situ XANES and EXAFS investigations of the catalysts have revealed that Cu+ ions are anchored onto Alz03 or SiO2 as planar 3-coordinate Cu+, while being anchored onto SiOz/A1203 as linear 2-coordinate Cu+. Photoluminescence measurements of the catalysts and...

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