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.

scholarly journals Theoretical investigation on the effect of the ligand on bis-silylation of C(sp)–C(sp) by Ni complexes

RSC Advances ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 1005-1010
Author(s):  
Li Hui ◽  
He Yuhan ◽  
Wang Jiaqi
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Transition Metal ◽  
Theoretical Investigation ◽  
Density Functional ◽  
Active Catalyst ◽  
Organic Ligand ◽  
Organic Complex ◽  
Functional Theory ◽  
Rate Determining Step

Density functional theory (DFT) is used to study the bis-silylation of alkynes catalyzed by a transition metal nickel–organic complex; the active catalyst, the organic ligand, the reaction mechanism, and rate-determining step are discussed in this paper.

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.

BONDING FEATURES AND REACTION MECHANISM OF THE OXIDATION OF 2-PROPANOL BY A Cp*Ir AMIDO COMPLEX

2010 ◽  
Vol 09 (supp01) ◽  
pp. 99-107
Author(s):  
LINGJUN LIU ◽  
SIWEI BI ◽  
MIN SUN ◽  
XIANGAI YUAN ◽  
PING LI
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Dft Calculations ◽  
Density Functional ◽  
Bond Distance ◽  
Mechanistic Study ◽  
Functional Theory ◽  
Rate Determining Step ◽  
Model Complex ◽  
Membered Transition State

The mechanistic study on the oxidation of 2-propanol by the model complex CpIr [κ2-(N,C)-( NHCMe2–2-C6H4)] (R) is performed using density functional theory (DFT) calculations. It is found that the rate-determining step is the hydrogen migration from 2-propanol to R via a six-membered transition state. The reaction is calculated to be favorable thermodynamically. To further understand the reaction mechanism, some bonding features are discussed, such as the correlation of the geometry of R and the Ir–N π bond involved, the transformation of the nitrogen hybridization, the variation of Ir–N bond distance, and so on.

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.

scholarly journals A computational study for the reaction mechanism of metal-free cyanomethylation of aryl alkynoates with acetonitrile

RSC Advances ◽  
2021 ◽  
Vol 11 (30) ◽  
pp. 18246-18251
Author(s):  
Selçuk Eşsiz
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Density Functional ◽  
Computational Study ◽  
Coupled Cluster ◽  
Functional Theory ◽  
Metal Free ◽  
Coupled Cluster Methods ◽  
High Level ◽  
Cluster Methods

A computational study of metal-free cyanomethylation and cyclization of aryl alkynoates with acetonitrile is carried out employing density functional theory and high-level coupled-cluster methods, such as [CCSD(T)].

scholarly journals Catalyzed Ethanol Chemical Looping Gasification Mechanism on the Perfect and Reduced Fe2O3 Surfaces

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1663
Author(s):  
Laixing Luo ◽  
Xing Zheng ◽  
Jianye Wang ◽  
Wu Qin ◽  
Xianbin Xiao ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Density Functional ◽  
Oxygen Carrier ◽  
Catalytic Decomposition ◽  
Density Functional Theory Calculations ◽  
Chemical Looping ◽  
Functional Theory ◽  
Barrier Energy ◽  
Gasification Technology

Biomass chemical looping gasification (CLG) is a novel gasification technology for hydrogen production, where the oxygen carrier (OC) transfers lattice oxygen to catalytically oxidize fuel into syngas. However, the OC is gradually reduced, showing different reaction activities in the CLG process. Fully understanding the CLG reaction mechanism of fuel molecules on perfect and reduced OC surfaces is necessary, for which the CLG of ethanol using Fe2O3 as the OC was introduced as the probe reaction to perform density functional theory calculations to reveal the decomposition mechanism of ethanol into the synthesis gas (including H2, CH4, ethylene, formaldehyde, acetaldehyde, and CO) on perfect and reduced Fe2O3(001) surfaces. When Fe2O3(001) is reduced to FeO0.375(001), the calculated barrier energy decreases and then increases again, suggesting that the reduction state around FeO(001) favors the catalytic decomposition of ethanol to produce hydrogen, which proves that the degree of reduction has an important effect on the CLG reaction.

scholarly journals Molecular simulation on mechanism of thiophene hydrodesulfurization on surface of Ni2P

2021 ◽  
pp. 014459872199495
Author(s):  
Songjian Du ◽  
Tingting Li ◽  
Xinwei Wang ◽  
Liqiang Zhang ◽  
Zhengda Yang ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Heavy Oil ◽  
Density Functional ◽  
Reaction Path ◽  
Functional Theory ◽  
Thiophene Hydrodesulfurization ◽  
Cracking Reaction ◽  
Materials Studio ◽  
Optimal Reaction

Hydrodesulfurization reaction, as the last step of hydrothermal cracking reaction, is of great significance for the reduction of viscosity and desulfurization of heavy oil. Based on Density Functional Theory and using Dmol3 module of Materials Studio, this research simulated the adsorption and hydrodesulfurization of thiophene on Ni2P (001) surface, and discussed the hydrodesulfurization reaction mechanism of thiophene on Ni2P (001) surface. It was found that the direct hydrodesulfurization of thiophene had more advantages than the indirect hydrodesulfurization of thiophene. Finally, the optimal reaction path was determined: C4H4S+H2→C4H6.

Sign in / Sign up

Export Citation Format

Share Document