نتایج جستجو برای: ethylene epoxidation

تعداد نتایج: 30626  

2001
M. Rocca L. Vattuone L. Savio U. Valbusa G. Comelli G. Paolucci E. J. Baerends

We show that in presence of subsurface oxygen, CO oxidation of oxygen precovered Ag~001! modifies the surface in such a way that CO adsorption is stabilized up to crystal temperatures of 160 K. When diffusion is activated new surface oxide phases form, characterized by oxygen both in surface and in subsurface sites and by a high density of states just below the Fermi level. Subsurface oxygen ac...

Journal: :Physical review letters 2010
Simone Piccinin Spiros Zafeiratos Catherine Stampfl Thomas W Hansen Michael Hävecker Detre Teschner Valerii I Bukhtiyarov Frank Girgsdies Axel Knop-Gericke Robert Schlögl Matthias Scheffler

Combining first-principles calculations and in situ photoelectron spectroscopy, we show how the composition and structure of the surface of an alloy catalyst is affected by the temperature and pressure of the reagents. The Ag-Cu alloy, recently proposed as an improved catalyst for ethylene epoxidation, forms a thin Cu-O surface oxide, while a Ag-Cu surface alloy is found not to be stable. Sever...

2011
Ngoc Linh Nguyen Simone Piccinin Stefano de Gironcoli

Ethylene oxide, obtained through partial oxidation of ethylene, is an important compound for the chemical industry, because it is widely used as an intermediate for the production of chemicals such as ethylene glycol, which finds applications as an antifreeze and as a precursor to polymers. The oxidation of ethylene can lead either to the desired product (ethylene oxide, EO) or to the formation...

Journal: :Chemical Engineering Journal 2021

Chemical looping epoxidation (CLE) of ethylene to oxide (EO) presents an exciting alternative the incumbent technology direct with O2(g). In CLE, reaction is still catalysed by Ag but oxygen provided as Olattice from a solid metal oxide, eliminating need and limitations using Here, influence catalyst preparation in CLE investigated. The was impregnated on SrFeO3, which used donor CLE. Temperatu...

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