نتایج جستجو برای: vanadium catalyst

تعداد نتایج: 51205  

2007
Olubunmi M. Ogunsola

Oil shale is more than an energy source. It is also a source for various valuable materials. These materials include pyridine, carbonate minerals, alumina, ammonium sulfate, phosphate, sulfur, uranium, vanadium, and zinc, to name a few, from which numerous value-added products can be manufactured. For example, catalysts are made from vanadium and zinc, while alumina is a widely used material fo...

2015
Seung Gwan Lee Hyun Jeong Lee Inhak Song Seunghee Youn Do Heui Kim Sung June Cho

Emission of N2O from mobile and off-road engine is now being currently regulated because of its high impact compared to that of CO2, thereby implying that N2O formation from the exhaust gas after-treatment system should be suppressed. Selective catalytic reduction using vanadium supported TiO2 catalyst in mobile and off-road engine has been considered to be major source for N2O emission in the ...

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...

Journal: :پژوهش نفت 0

a series of ethylene-propylene-2-ethylidenebicyclo [2.2.1] hept.5-ene terpolymers (epdm) have been prepared using a vocl3/al2et3cl3 catalyst under various al/v ratios and diene concentrations via solution polymerization and characterized by ftir, mooney viscosity (ml1+4,125oc), and thermal gravimetery analyzing. the polymerization yield was seen to increase with augmentation of the al/v ratio a...

2005
M. G. Willinger D. S. Su

Vanadium phosphorus oxides are used as catalysts in the selective oxidation of n-butane to maleic anhydride. The working catalyst comprises besides the main pyrophosphate phase in which the vanadium is in a 4+ oxidation state also a, predominantly preparation dependent, amount of different pentavalent vanadylorthophosphate phases. In order to elucidate the role of the pentavalent phases it is n...

2017
Alette G.J. Ligtenbarg Ronald Hage Ben L. Feringa

Vanadium haloperoxidases catalyse the oxidation of halides leading to halogenation of substrates or, in the absence of suitable substrates, to oxidation of hydrogen peroxide into singlet oxygen and water. Furthermore, V-haloperoxidases are capable to give enantioselective sulfoxidation under the appropriate conditions. The most interesting model compounds that have been synthesised and studied ...

2007
Guoan Du Sangyun Lim Mathieu Pinault Chuan Wang Fang Fang Lisa Pfefferle Gary L. Haller

Vanadium oxide grafted on mesoporous silica SBA-15 has been synthesized using a controlled grafting process. Its structure has been thoroughly investigated using different characterization techniques, including N2-physisorption, X-ray diffraction, transmission electron microscopy (TEM), Raman spectroscopy, H2 temperature-programmed reduction, X-ray absorption near-edge structure (XANES), and ex...

Journal: :The journal of physical chemistry. A 2007
Elena Jakubikova Elliot R Bernstein

Thermodynamics of reactions of vanadium oxide clusters with SO2 are studied at the BPW91/LANL2DZ level of theory. BPW91/LANL2DZ is insufficient to properly describe relative V-O and S-O bond strengths of vanadium and sulfur oxides. Calibration of theoretical results with experimental data is necessary to compute reliable enthalpy changes for reactions between VxOy and SO2. Theoretical results i...

2015
Lei Liu Patrick J. Carroll Marisa C. Kozlowski

The first regioselective oxidative coupling of 2-hydroxycarbazoles is described. With a vanadium catalyst and oxygen as the terminal oxidant, dimers with an ortho-ortho' coupling pattern were obtained with high selectivity. Further oxidation led to ortho'-ortho' coupling to generate a tetramer, which provided insight that the atropisomerization barriers of the unsymmetrical biaryl bonds are muc...

Journal: :Chemical communications 2011
Kaliyamoorthy Alagiri Guralamatta Siddappa Ravi Kumara Kandikere Ramaiah Prabhu

An aerobic oxidative cross-dehydrogenative coupling reaction between sp(3) C-H and sp(2) C-H bonds is developed by employing a vanadium catalyst (10 mol%) in an aqueous medium using molecular oxygen as the oxidant. This environmentally benign strategy exhibits larger substrate scope and shows high regioselectivity.

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