A density functional theory study of propylene epoxidation mechanism on Ag2O(001) surface

Date

2018-11-07

Author

Tezsevin, I.
van Santen, R. A.
Önal, Işık

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

129
views

0
downloads

Propylene oxide (PO) is one of the 50 most produced chemicals according to the production volume. Environmental and economic drawbacks of conventional PO production processes necessitate new production methods. Among the new production alternatives, direct epoxidation of propylene to propylene oxide by molecular oxygen is a highly desired method and seen as the holy grail of propylene epoxidation studies. In this study, the propylene epoxidation mechanism on an Ag2O(001) surface is investigated computationally by means of density functional theory (DFT) calculations using the Vienna Ab-initio Simulation Package (VASP). A perfect Ag2O(001) surface and a surface with one O vacancy are utilized for this purpose. It is found that propylene oxide can be directly formed on an Ag2O(001) surface whether there is an oxygen vacancy or not. The rate controlling step is PO desorption from both surfaces. PO isomers, i.e. acetone and propanal, can also be formed on these surfaces. However, activation barriers do exist for these molecules. Direct allyl formation on the Ag2O(001) surface is found to be unfavorable unlike what is proposed in the literature. On the other hand, it is observed that an allyl radical can be formed either via an oxametallocycle path or after the formation of propylene oxide. In fact, the discovered allyl radical formation pathway from propylene oxide is found as the most probable successive reaction pathway because of the high desorption barrier of PO.

Subject Keywords

Gas-phase epoxidation, Total-energy calculations, Wave basis-set, Molecular-oxygen, Ab-initio, Selective oxidation, Silver catalysts, oxide, Propene, Insights

URI

https://hdl.handle.net/11511/30717

Journal

PHYSICAL CHEMISTRY CHEMICAL PHYSICS

DOI

https://doi.org/10.1039/c8cp04210a

Collections

Graduate School of Natural and Applied Sciences, Article

Suggestions

OpenMETU
Core

A Review Of The Catalytic Conversion Of Glycerol To Lactic Acid İn The Presence Of Aqueous Base Akbulut, Doğan; Özkar, Saim (2022-06-01) Lactic acid is a high-value-added chemical with large production, which is used in many industries including the production of pyruvic and acrylic acids. Lactic acid is largely obtained from the oxidation of glycerol, which is a prevalent by-product of biodiesel production. However, the oxidation of glycerol to lactic acid requires harsh reaction conditions such as high temperature and pressure as well as the use of a hefty strong base. In the presence of suitable catalysts, the production of lactic acid fr...
Development of sol-gel catalysts by use of fast combinatorial synthesis and high throughput testing techniques for catalytic oxidation of propylene to propylene oxide Düzenli, Derya; Önal, Işık; Şeker, Erol; Department of Chemical Engineering (2010) Propylene oxide (PO) is an important raw material for the chemical industry, which is produced commercially by the chlorohydrin process and hydroperoxide process. However the deficiencies in these processes have given rise to considerable interest in the development of a direct route to PO that does not produce by-products or coproducts. The development of novel, active and selective catalysts for gas phase oxidation of propylene using molecular oxygen were studied via testing a large number of catalysts by...
A study of thin film solid phase microextraction methods for analysis of fluorinated benzoic acids in seawater Boyacı, Ezel; Viteri, C. Ricardo; Pawliszyn, Janusz (2016-03-04) Fluorinated benzoic acids (FBAs) are frequently used as tracers by the oil industry to characterize petroleum reservoirs. The demand for fast, reliable, robust, and sensitive approaches to separate and quantify FBAs in produced water, both in laboratory and field conditions, has not been yet fully satisfied. In this study, for the first time, thin film solid phase microextraction (TF-SPME) is proposed as a versatile sample preparation tool for the determination of FBAs in produced water by pursing two diffe...
A comparative evaluation of anaerobic dechlorination of PCB-118 and Aroclor 1254 in sediment microcosms from three PCB-impacted environments Kaya, Devrim; İmamoğlu, İpek; Sanin, Faika Dilek; Sowers, Kevin R. (Elsevier BV, 2018-01-05) Aroclor 1254 (A1254) is the most toxic commercial PCB mixture produced, primarily due to its relatively high concentrations of dioxin-like congeners. This study demonstrates a comparative evaluation of dechlorination of A1254 and PCB-118 by indigenous organohalide respiring bacteria enriched from three PCB impacted sites: Grasse River (GR), NY; Fox River (FR), WI; and Baltimore Harbor (BH), MD. PCB 118 dechlorination rates in GR, BH, and FR was 0.0308, 0.015, and 0.0006 Cl-/biphenyl/day, respectively. A1254...
Investigation on indigenous bacteria for individual BTEX degradation potentials and relative pathways used Yavaş, Alper; İçgen, Bülent; Parlaktuna, Mahmut; Department of Biotechnology (2018) Monoaromatic hydrocarbons including benzene, toluene, ethylbenzene and xylene collectively called as BTEX are found in the composition of crude oil and gasoline as an additive and thought to be the most serious contaminants of soil and groundwater. It is expected that indigenous bacteria isolated from petroleum hydrocarbon contaminated sites probably have degradation potential for the BTEX compounds. In this study, out of 22, 19 bacterial strains were selected as potential degraders for at least one of the ...

Citation Formats

I. Tezsevin, R. A. van Santen, and I. Önal, “A density functional theory study of propylene epoxidation mechanism on Ag2O(001) surface,” PHYSICAL CHEMISTRY CHEMICAL PHYSICS, pp. 26681–26687, 2018, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/30717.