Insight into the reaction mechanism and chemoselectivity in the cycloaddition of ynamides and isoxazoles with H2O

2020 ◽  
Vol 10 (1) ◽  
pp. 240-251 ◽  
Author(s):  
Lin Zhou ◽  
Li Yang ◽  
Songshan Dai ◽  
Yuanyuan Gao ◽  
Ran Fang ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Density Functional ◽  
Model Systems ◽  
Bronsted Acid ◽  
Functional Theory ◽  
Co Catalyst ◽  
The Density Functional Theory ◽  
Brönsted Acid ◽  
Insight Into

The mechanism and chemoselectivity in the cycloaddition of ynamides and isoxazoles have been explored by the density functional theory (DFT) in model systems composed of a Brønsted acid (HNTf2), gold(i) [IPrAuNTf2] or platinum(ii) (PtCl2/CO) catalyst.

Insight into the mechanism and site-selectivity of Rh2II,II(esp)2-catalyzed intermolecular C–H amination

2016 ◽  
Vol 6 (14) ◽  
pp. 5292-5303 ◽  
Author(s):  
Juping Wang ◽  
Cunyuan Zhao ◽  
Yuping Weng ◽  
Huiying Xu
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Functional Theory ◽  
Site Selectivity ◽  
The Density Functional Theory ◽  
Site Selective ◽  
Insight Into

The mechanisms and site-selective determinants of Rh2II,II(esp)2-catalyzed intermolecular C–H bond aminations of three isoamylbenzene-derived substrates, p-R–C6H4(CH2)2CH(CH3)2 (R = OCH3, H, CF3), have been investigated by the density functional theory (BPW91) method.

Selective hydrogenation of cinnamaldehyde catalyzed by Co-doped Pt clusters: a density functional theoretical study

RSC Advances ◽  
2016 ◽  
Vol 6 (91) ◽  
pp. 88277-88286 ◽  
Author(s):  
Laicai Li ◽  
Wei Wei ◽  
Wei Wang ◽  
Xiaolan Wang ◽  
Lin Zhang ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Selective Hydrogenation ◽  
Density Functional ◽  
Theoretical Study ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Co Doped

The reaction mechanism of the selective hydrogenation of cinnamaldehyde catalyzed by pure Pt clusters and Co-doped Pt clusters was studied by the density functional theory.

scholarly journals Theoretical Studies of Acrolein Hydrogenation to Propenol and Propanal on Au3 and Au5

2016 ◽  
Author(s):  
Guo-Jun Kang ◽  
Shuai He ◽  
Xue-Feng Ren
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Gold Clusters ◽  
The Other ◽  
Model Systems ◽  
Theoretical Studies ◽  
Functional Theory ◽  
Rate Determining Step ◽  
The Density Functional Theory ◽  
Supported Gold

The stepwise hydrogenation of the C=C bond and C=O group of acrolein on Au3 and Au5 model systems is investigated using the density functional theory(DFT) PW91 functional. Our results show that the C=C hydrogenation is more favorable than that of C=O bond on Au3 with the barriers of the rate-determining step being 0.35 and 0.62 eV respectively. On the other hand, the C=O reduction is preferred over the hydrogenation of the C=C bond on Au5. The corresponding barriers of the rate-determining steps are 0.45 and 0.54 eV, respectively. This demonstrated that the second hydrogenation step controls the reaction on both Au3 and Au5 for C=O and C=C hydrogenation and the C=O hydrogenation on Au5 is preferred over the hydrogenation of the C=C bond, which is helpful to address the reactivity of small size-selected supported gold clusters.

CO-ADSORPTION CALCULATIONS OF CO AND H2O MOLECULES ON ATOMIC CU CLUSTER DEPOSITED ZNO SURFACE: A DENSITY FUNCTIONAL THEORY STUDY

2020 ◽  
Vol 27 (03) ◽  
Author(s):  
VO THANH CONG ◽  
QUY DIEM DO ◽  
PHAM THANH TAM ◽  
VAN THANH KHUE ◽  
PHAM VAN TAT
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Density Functional ◽  
Co Adsorption ◽  
Surface Model ◽  
Density Functional Theory Study ◽  
Functional Theory ◽  
Copper Clusters ◽  
Adsorption Of Co ◽  
Insight Into

Calculations of adsorption and reaction mechanism on ZnO  surface have been investigated. In this work, the deposition of six atomic copper clusters (6Cu) on ZnO  surface (called 6Cu/ZnO  model), using density functional theory was employed to calculate for CO and H2O co-adsorption. In performance, on ZnO  surface, 6Cu were adsorbed to obtain four stable sites of 6Cu/ZnO model, called as 6Cu-I, 6Cu-II, 6Cu-III, and 6Cu-IV. The calculated results found that the 6Cu-IV was the most stable surface model, thus, used to examine the co-adsorption of CO and H2O molecules. Further, CO and H2O co-adsorption on ZnO  surface were calculated also to compare with 6Cu/ZnO surface. Based on co-adsorption energy calculations indicated that CO and H2O co-adsorption on 6Cu/ZnO surface were more favorable than on ZnO  surface. The studied results will provide an insight into the effective adsorption of cluster on ZnO-based surface by deposition.

scholarly journals Mechanistic insight into propane dehydrogenation into propylene over chromium (III) oxide by cluster approach and Density Functional Theory calculations

2020 ◽  
Vol 11 (4) ◽  
pp. 342-350
Author(s):  
Toyese Oyegoke ◽  
Fadimatu Nyako Dabai ◽  
Adamu Uzairu ◽  
Baba El-Yakubu Jibril
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Density Functional ◽  
Reaction Pathway ◽  
Hydrogen Abstraction ◽  
Propane Dehydrogenation ◽  
Propane Conversion ◽  
Functional Theory ◽  
Rate Determining Step ◽  
Insight Into

A preliminary study to provides insight into the kinetic and thermodynamic assessment of the reaction mechanism involved in the non-oxidative dehydrogenation (NOD) of propane to propylene over Cr2O3, using a density functional theory (DFT) approach, has been undertaken. The result obtained from the study presents the number of steps involved in the reaction and their thermodynamic conditions across different routes. The rate-determining step (RDS) and a feasible reaction pathway to promote propylene production were also identified. The results obtained from the study of the 6-steps reaction mechanism for dehydrogenation of propane into propylene identified the first hydrogen abstraction and hydrogen desorption to be endothermic. In contrast, other steps that include propane’s adsorption, hydrogen diffusion, and the second stage of hydrogen abstraction were identified as exothermic. The study of different reaction routes presented in the energy profiles confirms the Cr-O (S1, that is, the reaction pathway that activates the propane across the Cr-O site at the alpha or the terminal carbon of the propane) pathway to be the thermodynamically feasible pathway for the production of propylene. The first hydrogen abstraction step was identified as the potential rate-determining step for defining the rate of the propane dehydrogenation process. This study also unveils that the significant participation of Cr sites in the propane dehydrogenation process and how the Cr high surface concentration would hinder the desorption of propylene and thereby promote the production of undesired products due to the stronger affinity that exists between the propylene and Cr-Cr site, which makes it more stable on the surface. These findings thereby result in Cr-site substitution suggestion to prevent deep dehydrogenation in propane conversion to propylene. This insight would aid in improving the catalyst performance.

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