نتایج جستجو برای: reuseable catalysts

تعداد نتایج: 32969  

2017
Ana Franco Sudipta De Alina M Balu Araceli Garcia Rafael Luque

Vanillin is one of the most commonly used natural products, which can also be produced from lignin-derived feedstocks. The chemical synthesis of vanillin is well-established in large-scale production from petrochemical-based starting materials. To overcome this problem, lignin-derived monomers (such as eugenol, isoeugenol, ferulic acid etc.) have been effectively used in the past few years. How...

2017
Przemysław J. Jodłowski Roman J. Jędrzejczyk Damian K. Chlebda Anna Dziedzicka Łukasz Kuterasiński Anna Gancarczyk Maciej Sitarz

The aim of this study was to obtain nanocrystalline mixed metal-oxide-ZrO₂ catalysts via a sonochemically-induced preparation method. The effect of a stabiliser's addition on the catalyst parameters was investigated by several characterisation methods including X-ray Diffraction (XRD), nitrogen adsorption, X-ray fluorescence (XRF), scanning electron microscopy (SEM) equipped with energy dispers...

2010
R. P. PRAJAPATI D. R. TIWARI

Spent catalysts are principally solid waste which that coming out from nitrogenous fertilizer industry, during the production of ammonia, resulting in the production of large amount of solid waste containing nickel, which is the spent or deactivated catalysts. These catalysts contain from 12-14% nickel based on the production process in fertilizer industry disposal of spent catalyst is a proble...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2005
Christophe Letondor Nicolas Humbert Thomas R Ward

Most physiological and biotechnological processes rely on molecular recognition between chiral (handed) molecules. Manmade homogeneous catalysts and enzymes offer complementary means for producing enantiopure (single-handed) compounds. As the subtle details that govern chiral discrimination are difficult to predict, improving the performance of such catalysts often relies on trial-and-error pro...

2002
Senzi Li Sundaram Krishnamoorthy Anwu Li George D. Meitzner Enrique Iglesia

Iron-based catalysts were prepared by using promoters (K, Ru, Cu) and synthesis and activation protocols that inhibit sintering of oxide precursors and favor the nucleation of small Fe carbide crystallites. The effects of promoters on reduction/carburization behavior, on Fischer–Tropsch synthesis (FTS) rates, and on the number of CO binding sites formed during reaction were examined by combinin...

Journal: :Chemical communications 2012
Stefania Guizzetti Maurizio Benaglia Jay S Siegel

Poly(methylhydrosiloxane) (PMHS) supported organic catalysts promoted the Diels-Alder reaction of dienes with α,β-unsaturated aldehydes, also in pure water, in yields and enantiomeric excesses comparable to those observed with the non-supported catalysts (up to 93% ee). Recycling of the catalysts was performed with no loss of enantioselectivity for at least five reaction cycles.

2013
Akio TANAKA Kensuke MAEKAWA Kimichi SUZUKI

reactants, reagents, and catalysts. A wide variety of performances of transition-metal catalysts are considerably dependent on the electronic states belonging to d-orbital electrons having dif ferent oxidative or spin states designed by coordinated ligands. To explore high-performance catalysts, analytical investigation based on electronic states is necessary, and theoretical calculations are i...

2015

The present invention relates to new Nickel catalysts of Formula I and II and to the process of preparation of the new catalysts. These new catalysts are used in preparing poly(3-substitutedthiophene) with high regioregularity. Highly regioregular poly(3-substituted-thiophene) can be used in the manufacture of optoelectronic devices. Patent application No.523/MUM/2014

Journal: :Chemical communications 2005
Kevin Blann Annette Bollmann John T Dixon Fiona M Hess Esna Killian Hulisani Maumela David H Morgan Arno Neveling Stephanus Otto Matthew J Overett

In situ prepared chromium catalysts containing bulky diphosphinoamine (PNP) ligands, upon activation with MAO, are extremely efficient catalysts for the trimerisation of ethylene to 1-hexene.

Journal: :Chemical communications 2008
David P Serrano Juan Angel Botas Patricia Pizarro Rut Guil-López Gema Gómez

Ordered mesoporous carbons have been applied, for the first time, as catalysts for hydrogen production via methane decomposition, showing higher and more stable activity than commercial carbonaceous catalysts.

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