نتایج جستجو برای: catalyst selectivity

تعداد نتایج: 86617  

Journal: :Chemical communications 2005
Kohsuke Mori Yohei Mitani Takayoshi Hara Tomoo Mizugaki Kohki Ebitani Kiyotomi Kaneda

A zinc-based hydroxyapatite catalyst in conjunction with a Lewis base proved to be efficient for the coupling of CO2 and epoxide in the absence of additional organic solvents under an atmospheric CO2 pressure; the work-up procedure is straightforward and the catalyst could be reused without loss of catalytic activity and selectivity.

Journal: :Organic & biomolecular chemistry 2009
Vivek Polshettiwar Rajender S Varma

A magnetic nanoparticle-supported Pd catalyst was readily prepared from inexpensive starting materials and shown to catalyze various oxidation reactions with high turnover number (TON) and excellent selectivity. The ease of recovery using an external magnetic field, high activity, and the intrinsic stability of the catalyst make this protocol economic and sustainable.

Ahmad Tavasoli, Ali Nakhaeipour Sanaz Anahid

The effects of confinement in carbon nanotubes on Fischer-Tropsch (FT) activity, selectivity and lifetime of Carbon NanoTubes (CNTs) supported iron catalysts are reported. A method was developed to control the position of the catalytic sites on either inner or outer surface of carbon nanotubes. TEM analyses revealed that more than 80% of iron oxide particles can be controlled to be position...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور استان یزد - دانشگاه پیام نور مرکز اردکان - دانشکده علوم 1384

چکیده ندارد.

2017
N. R. Shiju D. R. Brown K. Wilson G. Rothenberg

The catalytic dehydration of glycerol to acrolein is investigated over silica-supported niobia catalysts in a continuous fixed-bed gas-phase reactor. Various supported niobia catalysts are prepared and characterized using surface analysis and spectroscopic methods (XRD, UV–Vis, XPS, N2 adsorption), as well as with ammonia adsorption microcalorimetry. Good results are obtained with initial glyce...

2009
Andreas Haghofer Karin Föttinger Frank Girgsdies Axel Knop-Gericke Robert Schlögl Günther Rupprechter

Methanol steam reforming is a promising reaction in terms of hydrogen production for use in PEM fuel cells. Catalyst research has focused mainly on Cu/ZnO formulations, because of their superior selectivity to CO2 and H2. The common byproduct CO is problematic due to its poisoning effect on the anode of a downstream fuel cell. Some years ago it was shown that palladium supported on certain redu...

Steam reforming of methanol can be considered as an attractive reaction aiming at hydrogen production for PEM fuel cells. Although Cu/Al-contained catalysts are considerably evaluated in this reaction, further evaluation is essential to evaluate the impact of some promoters like Pt in order to find a comprehensively optimized catalyst. Pt promoter is employed with different methods in this ...

2014
Edward I Balmond David Benito-Alifonso Diane M Coe Roger W Alder Eoghan M McGarrigle M Carmen Galan

A practical approach has been developed to convert glucals and rhamnals into disaccharides or glycoconjugates with high α-selectivity and yields (77-97%) using a trans-fused cyclic 3,4-O-disiloxane protecting group and TsOH⋅H2O (1 mol%) as a catalyst. Control of the anomeric selectivity arises from conformational locking of the intermediate oxacarbenium cation. Glucals outperform rhamnals becau...

2017
R. Thakur S. Barman

In the present study, transalkylation of 1,4-diispropylbenzene (DIPB) with benzene in the presence of modified beta zeolite was performed to produce cumene in a fixed bed reactor. Beta zeolite was exchanged with cerium in order to modify its catalytic activity. Activity of the modified catalyst was evaluated in the range of temperature 493K–593K, space time 4.2 kg h/kmol–9.03 kg h/k mol and ben...

Journal: :Chemical communications 2013
Taichi Kano Hisashi Sugimoto Osamu Tokuda Keiji Maruoka

Unusual anti-selectivity was observed in the conjugate addition of aldehydes to nitroalkenes, when a biphenyl-based chiral secondary amine was used as catalyst.

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