A computational (DFT) study on aza-Claisen rearrangement: Effect of temperature, solvent and substitution on activation barrier

2014 ◽  
Vol 1046 ◽  
pp. 42-48 ◽  
Author(s):  
Sudarshan Debnath ◽  
Shovan Mondal
Keyword(s):  
Claisen Rearrangement ◽  
Activation Barrier ◽  
Dft Study ◽  
Effect Of Temperature ◽  
Rearrangement Effect

A single-atom catalyst of cobalt supported on a defective two-dimensional boron nitride material as a promising electrocatalyst for the oxygen reduction reaction: a DFT study

2019 ◽  
Vol 21 (13) ◽  
pp. 6900-6907 ◽  
Author(s):  
Chaofang Deng ◽  
Rongxing He ◽  
Wei Shen ◽  
Ming Li ◽  
Tao Zhang
Keyword(s):  
Boron Nitride ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Activation Barrier ◽  
Reduction Reaction ◽  
Dft Study ◽  
Single Atom ◽  
Two Dimensional ◽  
Nitride Material

Single cobalt atoms supported by a defective two-dimensional boron nitride material catalyze the ORR via a direct 4e− pathway with a largest activation barrier of 0.3 eV.

Gosteli−Claisen Rearrangement: DFT Study of Substituent−Rate Effects

2009 ◽  
Vol 74 (11) ◽  
pp. 4336-4342 ◽  
Author(s):  
Julia Rehbein ◽  
Martin Hiersemann
Keyword(s):  
Claisen Rearrangement ◽  
Dft Study ◽  
Rate Effects

Preparation of CdS and CdS@Zn3(PO4)2 Nanocomposites by Sol-Gel Method: DFT Study and Effect of Temperature on Band Gap

2020 ◽  
Vol 65 (9) ◽  
pp. 1424-1435 ◽  
Author(s):  
Sandeep Arya ◽  
Asha Sharma ◽  
Anoop Singh ◽  
Aamir Ahmed ◽  
Sarika Mahajan
Keyword(s):  
Band Gap ◽  
Sol Gel ◽  
Dft Study ◽  
Effect Of Temperature ◽  
Gel Method ◽  
Sol Gel Method

DFT study of phenol alkylation with propylene on H-BEA in the absence and presence of water

2021 ◽  
Author(s):  
Sajal Kanti Dutta ◽  
Vishal Agarwal
Keyword(s):  
Transition State ◽  
Transition State Theory ◽  
Rate Coefficient ◽  
Activation Barrier ◽  
State Theory ◽  
Dft Study ◽  
Phenol Alkylation ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Rate Limiting

Water reduces the activation barrier of the rate-limiting step of phenol alkylation with propylene in H-BEA. This, in turn, increases the transition-state theory rate coefficient by two orders-of-magnitude, suggesting much faster alkylation.

Nucleation of Disorder in Fe3Al Alloys

1967 ◽  
Vol 25 ◽  
pp. 312-313
Author(s):  
P. R. Swann ◽  
W. R. Duff ◽  
R. M. Fisher
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Annealing Temperature ◽  
Antiphase Domain ◽  
Effect Of Temperature ◽  
Domain Structures ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Higher Temperature ◽  
The One

Recently we have investigated the phase equilibria and antiphase domain structures of Fe-Al alloys containing from 18 to 50 at.% Al by transmission electron microscopy and Mössbauer techniques. This study has revealed that none of the published phase diagrams are correct, although the one proposed by Rimlinger agrees most closely with our results to be published separately. In this paper observations by transmission electron microscopy relating to the nucleation of disorder in Fe-24% Al will be described. Figure 1 shows the structure after heating this alloy to 776.6°C and quenching. The white areas are B2 micro-domains corresponding to regions of disorder which form at the annealing temperature and re-order during the quench. By examining specimens heated in a temperature gradient of 2°C/cm it is possible to determine the effect of temperature on the disordering reaction very precisely. It was found that disorder begins at existing antiphase domain boundaries but that at a slightly higher temperature (1°C) it also occurs by homogeneous nucleation within the domains. A small (∼ .01°C) further increase in temperature caused these micro-domains to completely fill the specimen.

The effect of temperature on high-resolution TEM image contrast

1995 ◽  
Vol 53 ◽  
pp. 640-641
Author(s):  
T. Geipel ◽  
W. Mader ◽  
P. Pirouz
Keyword(s):  
Form Factor ◽  
Inelastic Scattering ◽  
Accurate Method ◽  
Waller Factor ◽  
Effect Of Temperature ◽  
Specimen Thickness ◽  
Influence Of Temperature ◽  
Debye Waller Factor ◽  
Influence Of Temperature On ◽  
Atomic Form Factor

Temperature affects both elastic and inelastic scattering of electrons in a crystal. The Debye-Waller factor, B, describes the influence of temperature on the elastic scattering of electrons, whereas the imaginary part of the (complex) atomic form factor, fc = fr + ifi, describes the influence of temperature on the inelastic scattering of electrons (i.e. absorption). In HRTEM simulations, two possible ways to include absorption are: (i) an approximate method in which absorption is described by a phenomenological constant, μ, i.e. fi; - μfr, with the real part of the atomic form factor, fr, obtained from Hartree-Fock calculations, (ii) a more accurate method in which the absorptive components, fi of the atomic form factor are explicitly calculated. In this contribution, the inclusion of both the Debye-Waller factor and absorption on HRTEM images of a (Oll)-oriented GaAs crystal are presented (using the EMS software.Fig. 1 shows the the amplitudes and phases of the dominant 111 beams as a function of the specimen thickness, t, for the cases when μ = 0 (i.e. no absorption, solid line) and μ = 0.1 (with absorption, dashed line).

Sign in / Sign up

Export Citation Format

Share Document