Efficient Cu catalyst for 5-hydroxymethylfurfural hydrogenolysis by forming Cu–O–Si bonds

2020 ◽  
Vol 10 (21) ◽  
pp. 7323-7330
Author(s):  
Yifeng Zhu ◽  
Xiao Kong ◽  
Bo Peng ◽  
Luping Li ◽  
Zhen Fang ◽  
...  
Keyword(s):  
Covalent Bonding ◽  
Cu Catalyst ◽  
Strong Covalent Bonding

Strong covalent bonding (Cu–O–Si) modulates the Cu status and boosts the C–O hydrogenolysis.

Intrinsic Brittlement of Mo3Si by First-Principle Calculations

2013 ◽  
Vol 747-748 ◽  
pp. 63-68 ◽  
Author(s):  
Lai Qi Zhang ◽  
Wei Du ◽  
Meng Wang ◽  
Yong Ming Hou ◽  
Xiao Dong Ni ◽  
...  
Keyword(s):  
First Principles ◽  
Electronic Structures ◽  
Formation Energy ◽  
Covalent Bonding ◽  
First Principle ◽  
Nearest Neighbour ◽  
Experiment Data ◽  
First Principle Calculations ◽  
Strong Covalent Bonding ◽  
Good Agreement

First-principles method has been used to study the intrinsic brittlement of Mo3Si. The crystal constants, formation energy, cohesive energy, electronic structure, elastic constants of Mo3Si were calculated. The results were in good agreement with experiment data. Electronic structures showed that the strong covalent bonding between the nearest neighbour Mo atoms, which arrange perpendicularly each other, leads to embrittlement of Mo3Si.

scholarly journals Strong covalent bonding between two graphene layers

2008 ◽  
Vol 77 (4) ◽  
Author(s):  
P. L. de Andres ◽  
R. Ramírez ◽  
J. A. Vergés
Keyword(s):  
Covalent Bonding ◽  
Graphene Layers ◽  
Strong Covalent Bonding

Strong Covalent Bonding for Enhanced Negative Thermal Expansion in (1 – x)PbTiO3–xBiGaO3

2020 ◽  
Vol 124 (37) ◽  
pp. 20445-20449 ◽  
Author(s):  
Tao Yang ◽  
Yilin Wang ◽  
Longlong Fan ◽  
Na Wang ◽  
Kun Lin ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Negative Thermal Expansion ◽  
Covalent Bonding ◽  
Strong Covalent Bonding

The role of added pyridine in substitution reactions of triphenylmethyl chloride in benzene solution

1967 ◽  
Vol 45 (13) ◽  
pp. 1497-1503
Author(s):  
K. T. Leffek ◽  
R. G. Waterfield
Keyword(s):  
Quaternary Ammonium ◽  
Benzene Solution ◽  
Alkyl Halide ◽  
Covalent Bonding ◽  
Kinetic Investigation ◽  
Exchange Reactions ◽  
Substitution Reactions ◽  
Kinetics Of ◽  
Strong Covalent Bonding

A detailed kinetic investigation has been made of the specific role of pyridine when added to the methanolysis and radiochloride exchange reactions of triphenylmethyl chloride in benzene. It is concluded that neither of the two proposals in the literature, i.e. that it reacts with the alkyl halide to form a quaternary ammonium salt or that it has no effect whatever except to take up the hydrogen chloride product, is correct. The present results indicate that pyridine forms a complex with the triphenylmethyl chloride, without strong covalent bonding, which has a distinctive effect on the kinetics of the reactions.

scholarly journals First-principles Study of Vickers Hardness and Thermodynamic Properties of Ti3SnC2 Polymorphs

2015 ◽  
Vol 7 (3) ◽  
pp. 53-64 ◽  
Author(s):  
M. A. Rayhan ◽  
M. A. Ali ◽  
S. H. Naqib ◽  
A. K. M. A. Islam
Keyword(s):  
Thermodynamic Properties ◽  
Vickers Hardness ◽  
First Principles ◽  
Applied Pressure ◽  
Theoretical Data ◽  
Debye Model ◽  
Covalent Bonding ◽  
First Principles Calculations ◽  
Specific Heats ◽  
Strong Covalent Bonding

We have investigated Vickers hardness and the thermodynamic properties of the recently discovered nanolaminate carbide Ti3SnC2 polymorphs using the first-principles calculations. The chemical bonding shows a combination of covalent, ionic and metallic types. The strong covalent bonding is mainly responsible for high Vickers hardness of Ti3SnC2 polymorphs. Thermodynamic properties are studied using the quasi-harmonic Debye model. The variation of bulk modulus, thermal expansion coefficient, specific heats, and Debye temperature with applied pressure (P) and temperature (T) are investigated systematically within the ranges of 0 - 50 GPa and 0 - 1000 K. The calculated results have been compared with available experimental and theoretical data.

Electronic properties of SmxSr1−xMnO3 for solid oxide fuel cell application — a first-principles study

2021 ◽  
Author(s):  
S. Vijayalakshmi ◽  
S. Mahalakshmi ◽  
M. Muthujothi
Keyword(s):  
Electronic Properties ◽  
First Principles ◽  
Electronic Conductivity ◽  
Covalent Bonding ◽  
Solid Oxide ◽  
First Principles Calculation ◽  
Oxide Fuel ◽  
Metallic Behavior ◽  
Fuel Cell Application ◽  
Strong Covalent Bonding

Electronic properties of orthorhombic SSM ([Formula: see text] and monoclinic SSM ([Formula: see text] are investigated using the first-principles calculation. The half-metallic behavior that leads to the mixed ionic and electronic conductivity (MIEC) property is identified in orthorhombic SSM. In addition, the strong covalent bonding between [Formula: see text]-p and [Formula: see text]-s orbitals of orthorhombic SSM is identified from the PDOS plot. The strong covalent bonding enhances the [Formula: see text] molecular adsorption on Mn atom. On the other hand, monoclinic SSM shows the pure conducting behavior and there is no covalent bonding between Mn and O atoms. Thus, the results suggest that the half-metal Sm[Formula: see text]Sr[Formula: see text]MnO3 might be a suitable cathode material for intermediate-temperature solid oxide fuel cells.

ANIPE-Cu Catalyst Enables Highly Enantioselective Markovnikov Hydroboration of α-Olefins

Synlett ◽  
2020 ◽  
Author(s):  
Shi-Liang Shi ◽  
Yuan Cai
Keyword(s):  
Petrochemical Industry ◽  
Future Directions ◽  
Asymmetric Hydroboration ◽  
Terminal Alkenes ◽  
Cu Catalyst

AbstractAsymmetric hydroboration of simple and unactivated terminal alkenes (α-olefins), feedstock chemicals derived from the petrochemical industry, has not been efficiently realized for past decades. Using a bulky ANIPE ligand, we achieved a rare example of highly enantioselective copper-catalyzed Markovnikov hydroboration of α-olefins. The chiral secondary alkylboronic ester products were obtained in moderate to good yields and regioselectivities with excellent enantioselectivities.1 Introduction2 Conditions Optimization3 Substrate Scope4 Application5 Mechanistic Discussion6 Conclusions and Future Directions

scholarly journals Production of Fuels and Chemicals from a CO2/H2 Mixture

Reactions ◽  
2020 ◽  
Vol 1 (2) ◽  
pp. 130-146
Author(s):  
Yali Yao ◽  
Baraka Celestin Sempuga ◽  
Xinying Liu ◽  
Diane Hildebrandt
Keyword(s):  
Co2 Hydrogenation ◽  
Water Gas Shift ◽  
Liquid Fuels ◽  
Saturated Hydrocarbons ◽  
Reverse Water Gas Shift ◽  
Cu Catalyst ◽  
In Series ◽  
Fuels And Chemicals ◽  
Water Gas ◽  
Aspen Simulation

In order to explore co-production alternatives, a once-through process for CO2 hydrogenation to chemicals and liquid fuels was investigated experimentally. In this approach, two different catalysts were considered; the first was a Cu-based catalyst that hydrogenates CO2 to methanol and CO and the second a Fisher–Tropsch (FT) Co-based catalyst. The two catalysts were loaded into different reactors and were initially operated separately. The experimental results show that: (1) the Cu catalyst was very active in both the methanol synthesis and reverse-water gas shift (R-WGS) reactions and these two reactions were restricted by thermodynamic equilibrium; this was also supported by an Aspen plus simulation of an (equilibrium) Gibbs reactor. The Aspen simulation results also indicated that the reactor can be operated adiabatically under certain conditions, given that the methanol reaction is exothermic and R-WGS is endothermic. (2) the FT catalyst produced mainly CH4 and short chain saturated hydrocarbons when the feed was CO2/H2. When the two reactors were coupled in series and the presence of CO in the tail gas from the first reactor (loaded with Cu catalyst) significantly improves the FT product selectivity toward higher carbon hydrocarbons in the second reactor compared to the standalone FT reactor with only CO2/H2 in the feed.

Non-Covalent Bonding Interaction between Primaquine as Guest and 2-(Hydroxypropyl)-β-Cyclodextrin as Host

2020 ◽  
pp. 1-18
Author(s):  
Moorthiraman Murugan ◽  
Rajaram Rajamohan ◽  
Arumugam Anitha ◽  
Madi Fatiha
Keyword(s):  
Covalent Bonding ◽  
Bonding Interaction
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