Determination of the complexes between dimethylphenols and pyridine by a dielectric constant method in non-polar solvents

1986 ◽  
pp. 573-578 ◽  
Author(s):  
Armando Codoñer ◽  
Isidro S. Monzó ◽  
Francisco Tomás ◽  
Rosa Valero
Keyword(s):  
Dielectric Constant ◽  
Polar Solvents

A new method for the determination of the dielectric constant in photoconductors

1966 ◽  
Vol 46 (2) ◽  
pp. 210-216 ◽  
Author(s):  
A. Carrelli ◽  
F. Fittipaldi ◽  
L. Pauciulo
Keyword(s):  
Dielectric Constant ◽  
New Method

scholarly journals Thermodynamics of primary antioxidant action of flavonols in polar solvents

2019 ◽  
Vol 12 (1) ◽  
pp. 108-118 ◽  
Author(s):  
Martin Michalík ◽  
Ján Rimarčík ◽  
Vladimír Lukeš ◽  
Erik Klein
Keyword(s):  
Reaction Pathway ◽  
Hydrogen Atom Transfer ◽  
Antioxidant Effect ◽  
Antioxidant Action ◽  
Polar Solvents ◽  
Polar Media ◽  
Primary Antioxidant ◽  
Intramolecular Hydrogen

Abstract Very recently, a report on the antioxidant activity of flavonoids has appeared, where authors concluded that Hydrogen Atom Transfer mechanism represents the thermodynamically preferred mechanism in polar media (https://doi.org/10.1016/j.foodres.2018.11.018). Unfortunately, serious errors in the theoretical part of the paper led to incorrect conclusions. For six flavonols (galangin, kaempferol, quercetin, morin, myricetin, and fisetin), reaction enthalpies related to three mechanisms of the primary antioxidant action were computed. Based on the obtained results, the role of intramolecular hydrogen bonds (IHB) in the thermodynamics of the antioxidant effect is presented. Calculations and the role of solvation enthalpies of proton and electron in the determination of thermodynamically preferred mechanism is also briefly explained and discussed. The obtained results are in accordance with published works considering the Sequential Proton-Loss Electron-Transfer thermodynamically preferred reaction pathway.

scholarly journals Determination of the dipole moments of some polar liquids dissolved in polar solvents

1969 ◽  
Vol 47 (20) ◽  
pp. 3767-3771 ◽  
Author(s):  
H. A. Rizk ◽  
N. Youssef ◽  
H. Grace
Keyword(s):  
Dipole Moments ◽  
Butyl Alcohol ◽  
Polar Solvents ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Initial Decrease ◽  
Interacting Systems ◽  
Solvent Molecules ◽  
Onsager Equation

The application of a modified form of the Onsager equation at the condition of infinite dilution of a polar solute in a polar solvent leads to reasonable dipole moments for water, pyridine, acetone, tert-butyl alcohol, n-butyl alcohol, and β-octyl alcohol, except in the case of water in tert-butyl alcohol at 30 and 40 °C and the case of acetone in n-butyl alcohol at 30 to 50 °C. The initial decrease of the dielectric constant of solvent by addition of solute in each of these two cases is associated with a reduction in the Kirkwood g-factor of solute. In all 12 systems investigated, strong hydrogen bonding occurs between solute and solvent molecules and often between solvent molecules themselves. It is thought that this equation must fail when short-range interactions assume predominant importance, but why it works so well for those cases which are also strongly interacting systems is not clear.

scholarly journals Experimental determination of the dielectric constant of wheat grain and cluster straw in different moisture contents

2019 ◽  
Vol 8 (1) ◽  
pp. 629-635 ◽  
Author(s):  
Mohammad Jafari ◽  
Gholamreza Chegini ◽  
Behrooz Rezaeealam ◽  
Amir Abbas Shaygani Akmal
Keyword(s):  
Dielectric Constant ◽  
Experimental Determination ◽  
Wheat Grain ◽  
Moisture Contents
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