نتایج جستجو برای: catalyst

تعداد نتایج: 44027  

Journal: :Chemical communications 2011
Pradip K Maity Quirin M Kainz Saqib Faisal Alan Rolfe Thiwanka B Samarakoon Fatima Z Basha Oliver Reiser Paul R Hanson

The utilization of a monomer-on-monomer (MoM) intramolecular Mitsunobu cyclization reaction employing norbornenyl-tagged (Nb-tagged) reagents is reported for the synthesis of benzofused thiadiazepine-dioxides. Facile purification was achieved via ring-opening metathesis (ROM) polymerization initiated by one of three metathesis catalyst methods: (i) free metathesis catalyst, (ii) surface-initiat...

Journal: :Journal of the American Chemical Society 2010
Norito Takenaka Jinshui Chen Burjor Captain Robindro Singh Sarangthem Appayee Chandrakumar

Helical chiral 2-aminopyridinium ions were designed as a significantly more acidic (active) dual hydrogen-bonding catalyst than commonly used (thio)urea-based systems. The helicene framework was specifically utilized to position an inherently chiral barrier on the hydrogen-bonding side of the catalyst. The catalyst reactivity and enantioselectivity were successfully demonstrated in additions of...

2015
Tetsuo Umegaki Yoshiyuki Kojima Kohji Omata

The effect of oxide coating on the activity of a copper-zinc oxide-based catalyst for methanol synthesis via the hydrogenation of carbon dioxide was investigated. A commercial catalyst was coated with various oxides by a sol-gel method. The influence of the types of promoters used in the sol-gel reaction was investigated. Temperature-programmed reduction-thermogravimetric analysis revealed that...

2012
Eric Marceau

Aluminium oxide (Al2O3), commonly known as alumina, is a widespread naturally occurring compound that has a broad range of industrial applications. Besides its use as a pigment or abrasive, alumina also plays a vital role as catalyst support for desulfurization or hydrogenation reactions. In the latter case, the active phase on the catalyst often consists of nickel metal nanoparticles. The inte...

2017
Paul J. Smith Simon A. Kondrat Philip A. Chater Benjamin R. Yeo Greg M. Shaw Li Lu Jonathan K. Bartley Stuart H. Taylor Michael S. Spencer Christopher J. Kiely Gordon J. Kelly Colin W. Park Graham J. Hutchings

Zincian georgeite, an amorphous copper–zinc hydroxycarbonate, has been prepared by co-precipitation using acetate salts and ammonium carbonate. Incorporation of zinc into the georgeite phase and mild ageing conditions inhibits crystallisation into zincian malachite or aurichalcite. This zincian georgeite precursor was used to prepare a Cu/ZnO catalyst, which exhibits a superior performance to a...

2015
Sabina Caneva Robert S. Weatherup Bernhard C. Bayer Barry Brennan Steve J. Spencer Ken Mingard Andrea Cabrero-Vilatela Carsten Baehtz Andrew J. Pollard Stephan Hofmann

The scalable chemical vapor deposition of monolayer hexagonal boron nitride (h-BN) single crystals, with lateral dimensions of ∼0.3 mm, and of continuous h-BN monolayer films with large domain sizes (>25 μm) is demonstrated via an admixture of Si to Fe catalyst films. A simple thin-film Fe/SiO2/Si catalyst system is used to show that controlled Si diffusion into the Fe catalyst allows exclusive...

2014
Catharina Paukner Krzysztof K. K. Koziol

We report a new strategy towards the control of carbon nanotube (CNT) structure and continuous fibre formation using a floating catalyst direct spinning CVD process. In the procedures used to date, a sulphur promoter precursor is added to significantly enhance the rate of CNT formation in the floating catalyst synthesis. Within the reaction zone, the rapidly grown nanotubes self-assemble into b...

2013
Hongliang Peng Zaiyong Mo Shijun Liao Huagen Liang Lijun Yang Fan Luo Huiyu Song Yiliang Zhong Bingqing Zhang

Proton exchangemembrane fuel cells are promising candidates for a clean and efficient energy conversion in the future, the development of carbon based inexpensive non-precious metal ORR catalyst has becoming one of the most attractive topics in fuel cell field. Herein we report a Feand Ndoped carbon catalyst Fe-PANI/C-Mela with graphene structure and the surface area up to 702 m g. In 0.1 MHClO...

2014
Prabhakar Sharma Reena Dwivedi Rajiv Dixit Manohar Singh

A DFT modeling of the transition state of oxidative dehydrogenation of ethylbenzene over zirconium vanadate catalyst has been carried out. Computations confirm a Mars-Van-Krevelen type redox mechanism in which the catalyst abstracts a hydrogen atom from the hydrocarbon and catalyst is reduced. The reduced catalyst is reoxidized by oxygen from air. Computations suggest the formation of a hydroxy...

2016
Jing Liu Jing He Luying Wang Rong Li Pan Chen Xin Rao Lihong Deng Long Rong Jiandu Lei

Nickel oxide (NiO) and phosphotungstic acid (PTA) supported on a ZIF-8 (NiO-PTA/ZIF-8) catalyst was first synthesized and it showed high activity and good selectivity for the hydrocracking of Jatropha oil. The catalyst was characterized by SEM, SEM-EDS, TEM, N2 adsorption, FT-IR, XRD and XPS. Compared with the NiO-PTA/Al2O3 catalyst, the selectivity of C15-C18 hydrocarbon increased over 36%, an...

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