نتایج جستجو برای: catalysts

تعداد نتایج: 32940  

2008
Elizabeth I. Ross-Medgaarden William V. Knowles Taejin Kim Michael S. Wong Wu Zhou Christopher J. Kiely Israel E. Wachs

An extensive series of supported WO3/ZrOx (OH)4−2x catalysts (WZrOH) were synthesized by standard aqueous impregnation of ammonium metatungstate into an amorphous ZrOx (OH)4−2x metastable support, followed by high-temperature calcination (at 773–1173 K). The supported WZrOH catalysts were also compared with well-defined model supported WO3/ZrO2 catalysts (WZrO2) consisting of a thermally stable...

Journal: :Chemical communications 2007
Hengquan Yang Jun Li Jie Yang Zhimin Liu Qihua Yang Can Li

The encapsulation of homogeneous chiral catalysts, e.g. Co(Salen) and Ru-TsDPEN, in the mesoporous cage of SBA-16 is demonstrated; the encapsulated catalysts show performance as good as that of the homogeneous catalysts, and can be recycled for more than 10 times without significant loss of catalytic performance.

Journal: :journal of sciences islamic republic of iran 0

hantzsch 1,4-dihydropyridines are oxidized to the corresponding pyridine derivatives using oxygen or air and a mixture of the manganese and cobalt salts of parninobenzoic acid supported on silica gel as the catalysts. reactions are clean and the catalysts can be recovered easily and reused repeatedly.

Journal: :international journal of nano dimension 0
m. qandalee department of biology, garmsar branch, islamic azad university, garmsar, iran. m. hatami polymer research laboratory, university of bonab, bonab, i. r. iran. a. esmaeilzadeh department of chemistry, ayatollah amoli branch, islamic azad university, amol, iran. a. shojaeian department of chemistry, ayatollah amoli branch, islamic azad university, amol, iran. p. biparva department of basic sciences, sari agricultural sciences and natural resources university, p.o. box 578, sari 4818168984, iran.

two-component reaction of 2-aminobenzophenones with acetylenic esters in the presence of γ-al2o3 and cu/zno as suitable heterogeneous catalysts has been studied. nano γ-al2o3 and cu/zno showed high activities when used as surface catalysts for the synthesis of quinoline derivatives. after completion of the reaction, the catalyst was recovered and reused several times under the same reaction con...

Abbas Ali Khodadadi Ahmad Tavasoli, Ali Karimi Mohammad Ali Mousavian Yadollah Mortazavi

Accelerated deactivation of Co/Al2O3 catalysts in Fischer-Tropsch synthesis and the effect of Re and Ru as the catalytic promoters are reported. 15wt% Co/Al2O3 catalyst and 1wt% Ru and 1.4wt% Re  promoted cobalt catalysts have been formulated and extensively characterized. The deactivation of the unpromoted cobalt catalyst and those promoted with ...

Journal: :Dalton transactions 2013
Ian W Ashworth David J Nelson Jonathan M Percy

Initiation rates for Grubbs and Grubbs-Hoveyda second generation pre-catalysts have been measured accurately in a range of solvents. Solvatochromic fitting reveals different dependencies on key solvent parameters for the two pre-catalysts, consistent with different mechanisms by which the Grubbs and Grubbs-Hoveyda pre-catalysts initiate.

2016
Zhujun Wu Shuling Shen Long Li Minquan Sun Junhe Yang Frédéric Jaouen

In this review, we provide an overview of recent progress in nanocarbons with different dimensions as noble-metal-free co-catalysts for photocatalysts. We put emphasis on the interface engineering between nanocarbon co-catalysts and various semiconductor photocatalysts and the novel properties generating of nanocarbon co-catalysts, also including the synthesis and application of nanocarbon-base...

2016
Julia Wappel Roland C Fischer Luigi Cavallo Christian Slugovc Albert Poater

A straightforward synthesis utilizing the ring-opening metathesis polymerization (ROMP) reaction is described for acid-triggered N,O-chelating ruthenium-based pre-catalysts bearing one or two 8-quinolinolate ligands. The innovative pre-catalysts were tested regarding their behavior in ROMP and especially for their use in the synthesis of poly(dicyclopentadiene) (pDCPD). Bearing either the commo...

Journal: :Science 2017
Grazia Malta Simon A Kondrat Simon J Freakley Catherine J Davies Li Lu Simon Dawson Adam Thetford Emma K Gibson David J Morgan Wilm Jones Peter P Wells Peter Johnston C Richard A Catlow Christopher J Kiely Graham J Hutchings

There remains considerable debate over the active form of gold under operating conditions of a recently validated gold catalyst for acetylene hydrochlorination. We have performed an in situ x-ray absorption fine structure study of gold/carbon (Au/C) catalysts under acetylene hydrochlorination reaction conditions and show that highly active catalysts comprise single-site cationic Au entities who...

Journal: :Chemical reviews 2003
Harald Gröger

3.1. Overview 2807 3.2. Chiral Aluminum(III) Complexes as a Catalyst 2808 3.2.1. Aluminum(III)-Salen-Based Catalysts 2808 3.2.2. Aluminum(III)-Binaphthol-Based Catalysts 2810 3.3. Chiral Titanium(IV) Complexes as a Catalyst 2814 3.3.1. Titanium(IV)-Peptide-Based Catalysts 2814 3.3.2. Titanium(IV)-Diol-Based Catalysts 2817 3.4. Chiral Zirconium(IV) Complexes as a Catalyst 2818 3.4.1. The Catalyt...

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