scholarly journals Zirconocene-Catalyzed Dimerization of α-Olefins: DFT Modeling of the Zr-Al Binuclear Reaction Mechanism

Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3565 ◽  
Author(s):  
Ilya Nifant’ev ◽  
Alexander Vinogradov ◽  
Alexey Vinogradov ◽  
Stanislav Karchevsky ◽  
Pavel Ivchenko
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Molecular Hydrogen ◽  
Density Functional ◽  
Effective Agent ◽  
Functional Theory ◽  
Dft Simulation ◽  
Dft Modeling ◽  
Dft Simulations

Zirconocene-mediated selective dimerization of α-olefins usually occurs when precatalyst (η5-C5H5)2ZrCl2 is activated by minimal excess of methylalumoxane (MAO). In this paper, we present the results of density functional theory (DFT) simulation of the initiation, propagation, and termination stages of dimerization and oligomerization of propylene within the framework of Zr-Al binuclear mechanism at M-06x/DGDZVP level of theory. The results of the analysis of the reaction profiles allow to explain experimental facts such as oligomerization of α-olefins at high MAO/(η5-C5H5)2ZrCl2 ratios and increase of the selectivity of dimerization in the presence of R2AlCl. The results of DFT simulations confirm the crucial role of the presence of chloride in the selectivity of dimerization. The molecular hydrogen was found in silico and proven experimentally as an effective agent that increases the rate and selectivity of dimerization.

Theoretical study of NHC-catalyzed C-S bond cleavage and reconstruction reaction: Mechanism, stereoselectivity, and role of catalyst

2021 ◽  
Author(s):  
Yang Wang ◽  
Yue Liu ◽  
Kaili Gong ◽  
Han Zhang ◽  
Yu Lan ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Density Functional ◽  
Theoretical Study ◽  
Bond Cleavage ◽  
Functional Theory

A theoretical study of the mechanism of the N-heterocyclic carbene (NHC)-catalyzed C-S bond cleavage and reconstruction reaction of unsaturated thioesters was conducted using density functional theory (DFT). The origin of...

A Density Functional Theory Study of the Catalytic role of Ti atoms in Reversible Hydrogen Storage in the Complex Metal Hydride, NaAlH4

2005 ◽  
Vol 884 ◽  
Author(s):  
Santanu Chaudhuri ◽  
James T Muckerman
Keyword(s):  
Density Functional Theory ◽  
First Principles ◽  
Molecular Hydrogen ◽  
Density Functional ◽  
First Principles Calculations ◽  
Density Functional Theory Study ◽  
Functional Theory ◽  
Catalytic Role ◽  
Present Part

AbstractPresence of ∼2-4 % Ti is critical for reversible hydrogenation/rehydrogenation in NaAlH4. We have investigated the probable catalytic role of Ti in this complex multi-step process. The present part of our study concentrates on the rehydrogenation reaction, i.e., the reverse reaction that forms NaAlH4 from its constituent binary hydrides. First principles calculations using density functional theory (DFT) show that a particular arrangement of Ti atoms on the surface of Al metal promotes the chemisorption of molecular hydrogen. We also present comparisons with existing experimental data (EXAFS and TEM) to support the existence of such an arrangement on the surface.

Remote N–H Activation of Indole Aldehyde: An Investigation on Mechanism, Origin of Selectivities, and Role of the Catalyst

2022 ◽  
Author(s):  
Abhijit Shyam ◽  
Amit Kumar Pradhan ◽  
Paritosh Mondal
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Density Functional ◽  
Dft Method ◽  
Functional Theory

Density functional theory (DFT) method has been utilised to predict the reaction mechanism of the N-heterocyclic carbene (NHC) catalysed remote N–H activation in indole aldehyde for the synthesis of enantiomerically...

γ-Valerolactone-Introduced Controlled-Isomerization of Glucose for Lactic Acid Production over Sn-Beta Catalyst

2021 ◽  
Author(s):  
Xinpeng Zhao ◽  
Zhimin Zhou ◽  
hu luo ◽  
Yanfei Zhang ◽  
Wang Liu ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Lactic Acid ◽  
Dft Calculations ◽  
Acid Production ◽  
Density Functional ◽  
Lactic Acid Production ◽  
Hydrothermal Conversion ◽  
Functional Theory ◽  
Environment Friendly

Combined experiments and density functional theory (DFT) calculations provided insights into the role of the environment-friendly γ-valerolactone (GVL) as a solvent in the hydrothermal conversion of glucose into lactic acid...

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.

Density Functional Theory Study of Thiophene Desulfurization and Conversion of Desulfurization Product on Ni(111) Surface and Ni55 Cluster: Implication for the Mechanism of Reactive Adsorption Desulfurization over Ni/ZnO Catalysts

2021 ◽  
Author(s):  
Houyu Zhu ◽  
Xin Li ◽  
Naiyou Shi ◽  
Xuefei Ding ◽  
Zehua Yu ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Active Center ◽  
Density Functional ◽  
Density Functional Theory Study ◽  
Functional Theory ◽  
Reactive Adsorption ◽  
Adsorption Desulfurization

Ni/ZnO catalysts have been well recognized by industry and academia for exhibiting excellent desulfurization activities. However, intrinsic reaction mechanism on Ni active center is still obscure. Herein, we performed periodic...

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