Mechanistic Aspects of Propene Epoxidation by Hydrogen Peroxide. Catalytic Role of Water Molecules, External Electric Field, and Zeolite Framework of TS-1

2009 ◽  
Vol 49 (4) ◽  
pp. 833-846 ◽  
Author(s):  
Jernej Stare ◽  
Neil J. Henson ◽  
Juergen Eckert
1981 ◽  
Vol 36 (8) ◽  
pp. 868-875 ◽  
Author(s):  
Wolfram Baumann

Abstract The effect of an external electric field on the absorption and the double fluorescence of 4-cyano-N,N-dimethylaniline can be understood, taking into account reaction field induced polarizability effects. If a TICT state conformation emits the a-fiuorescence in dioxane, the permanent dipole moment in this state is only slightly larger than in the equilibrium ground state.


2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Tiago da Silva Arouche ◽  
Rosely Maria dos Santos Cavaleiro ◽  
Phelipe Seiichi Martins Tanoue ◽  
Tais Sousa de Sa Pereira ◽  
Tarciso Andrade Filho ◽  
...  

Heavy metal contamination in the world is increasing the impact on the environment and human life. Currently, carbon nanotubes and boron are some possible ideals for the nanofiltration of heavy metals due to the property of ion selectivity, optimized by the applications of the surface and the application of an external electric field. In this work, molecular dynamic was used to transport water with heavy metals under the force exerted by the electric field action inside nanotubes. This external electric field generates a propelling electrical force to expel only water molecules and retain ions. These metal ions were retained to pass through only water molecules, under constant temperature and pressure, for a time of 100 ps under the action of electric fields with values from 10-8 to 10-1 au. Each of the metallic contaminants evaluated (Pb2+, Cd2+, Fe2+, Zn2+, Hg2+) was subjected to molecular test simulations in the water. It was found that the measurement of the intensity of the electric field increased or the percentage of filtered water reduced (in both nanotubes), in which the intramolecular and intermolecular forces intensified by the action of the electric field contribute to retain the heavy metal ions due to the evanescent effect. The best results for nanofiltration in carbon and boron nanotubes occur under the field 10-8 au. Since the filtration in the boron nitride nanotubes, a small difference in the percentage of filtered water for the boron nitride nanotube was the most effective (90 to 98%) in relation to the carbon nanotube (80 to 90%). The greater hydrophobicity and thermal stability of boron nanotubes are some of the factors that contributed to this result.


2020 ◽  
Vol 22 (44) ◽  
pp. 25859-25868
Author(s):  
Z. Rahimi ◽  
A. Lohrasebi

The effects of application of external electric field on the dynamics of water molecules inside an Aquaporin channel, embedded within a stochastically fluctuating membrane, was modeled by means of the application of the molecular dynamics (MD) simulation method.


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