The effect of cation concentration on the nitrogen splitting constant of nitroxide free radicals

1990 ◽  
Vol 55 (10) ◽  
pp. 2377-2380
Author(s):  
Hamza A. Hussain
Keyword(s):  
Hydrogen Peroxide ◽  
Hydrogen Bonding ◽  
Free Radicals ◽  
Esr Spectroscopy ◽  
The Other ◽  
Tetraethylammonium Bromide ◽  
Splitting Constant ◽  
The One ◽  
Positively Charged ◽  
Two Equilibria

Nitroxide free radicals prepared from diethylamine, piperidine and pyrrolidine by oxidation with hydrogen peroxide were studied by ESR spectroscopy. The changes in the 14N splitting constant (aN) caused by the addition of KBr or tetraethylammonium bromide were measured in dependence on the concentration of the ions. For diethylamine nitroxide and piperidine nitroxide, the results are discussed in terms of two equilibria: the one, involving the anion, is associated with a gain or loss of hydrogen bonds to the nitroxide oxygen atom, the other is associated with the formation of solvent shared units involving the cation, which results in changes in the hydrogen bonding strenght. The large increase in the aN value in the case of pyrrolidine nitroxide is explained in terms of an interaction from one side of the positively charged N atom; the increase in aN in the case of diethylamine and piperidine nitroxides is explained in terms of interactions with both sides of the positively charged N atom.

Iodic Acid (HIO3) in Combination with Tetraethylammonium Bromide as a Catalyst for Selective and Accelerated Sulfoxidation

2005 ◽  
Vol 35 (21) ◽  
pp. 2805-2810 ◽  
Author(s):  
Paresh D. Salgaonkar ◽  
Vidyanand G. Shukla, ◽  
K. G. Akamanchi
Keyword(s):  
Tetraethylammonium Bromide ◽  
Iodic Acid

ChemInform Abstract: Tetraethylammonium Bromide-Catalyzed Oxidative Thioesterification of Aldehydes and Alcohols.

ChemInform ◽  
2014 ◽  
Vol 45 (21) ◽  
pp. no-no
Author(s):  
Xuebin Zhu ◽  
Yan Shi ◽  
Haibin Mao ◽  
Yixiang Cheng ◽  
Chengjian Zhu
Keyword(s):  
Tetraethylammonium Bromide

Supramolecular catalysis of _-oxycyclohexyl peroxides decomposition by tetraethylammonium bromide

2005 ◽  
pp. 162-171
Author(s):  
N Turovskii ◽  
I Opeida ◽  
E Raksha ◽  
E Turovskaya ◽  
N Kuznetzova ◽  
...  
Keyword(s):  
Tetraethylammonium Bromide ◽  
Supramolecular Catalysis

High Performance Liquid Chromatographic Determination of Furazolidone in Feed and Feed Premixes

1981 ◽  
Vol 64 (5) ◽  
pp. 1100-1104
Author(s):  
Robert L Smallidge ◽  
Norman W Rowe ◽  
Nandan D Wadgaonkar ◽  
Rodger W Stringham
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
High Performance ◽  
Colorimetric Assay ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Tetraethylammonium Bromide ◽  
Precision Data ◽  
Relative Standard ◽  
Field Samples

Abstract Furazolidone is separated from finished feeds by acetone-water extraction on a Goldfisch apparatus. Extracting solvent is removed, and the residue is dissolved in dimethylformamide-5% tetraethylammonium bromide (1 + 1), clarified, and chromatographed on a reverse phase C18 column. The mobile phase is CH3CN-2% acetic acid (20 + 80) with detection at 365 nm. The method was tested for linearity, recovery, and ruggedness, and compared with the AOAC colorimetric assay by using field samples containing 0.0055-0.055% furazolidone. Precision data suggest a cumulative relative standard deviation of 1.43% within days and 1.78% between days. The ruggedness test predicts a between-laboratory relative standard deviation of 3.67%. Recovery was 97.5 ± 2.0% and linearity was excellent (r2 = 0.9994) up to 0.06% furazolidone. Premixes are extracted by shaking with dimethylformamide. An aliquot of the extract is diluted (1 + 1) with 5% tetraethylammonium bromide, clarified, and chromatographed.

scholarly journals Tetraethylammonium Acetate and Tetraethylammonium Bromide-Based Deep Eutectic Solvents as Thermodynamic CO2 Gas Hydrate Inhibitors

2020 ◽  
Vol 10 (19) ◽  
pp. 6794
Author(s):  
Vinayagam Sivabalan ◽  
Nurasyikin Hasnor ◽  
Bhajan Lal ◽  
Zamzila Kassim ◽  
Abdulhalim Shah Maulud
Keyword(s):  
Hydrogen Bond ◽  
Ethylene Glycol ◽  
Gas Hydrate ◽  
Deep Eutectic Solvents ◽  
Molar Ratio ◽  
Tetraethylammonium Bromide ◽  
Hydrate Dissociation ◽  
Co2 Gas ◽  
Vapor Equilibrium ◽  
Liquid Vapor

The thermodynamic gas hydrate suppression behavior of four Deep Eutectic Solvents (DESs) was evaluated in this paper. The mixtures of Hydrogen Bond Acceptors (HBA), Tetraethylammonium Acetate (TEAAC), and Tetraethylammonium Bromide (TEAB) with Hydrogen Bond Donors (HBD), Mono-Ethylene Glycol (MEG), and Glycerol were used to make the DES. The DESs were made at a 1:7 molar ratio for the combinations of TEAAC:MEG, TEAAC:Glycerol, TEAB:MEG, and TEAB:Glycerol. The Hydrate Liquid-Vapor Equilibrium (HLVE) data for CO2 were evaluated through the T-cycle method at different temperature (273.15–283.15 K) and pressure (2–4 MPa) conditions in the presence and absence of 5 wt % aqueous DES solutions. The inhibition effects showed by the DESs, including average suppression temperature (ΔŦ) and gas hydrate dissociation enthalpies (ΔHdiss), were also calculated. The average suppression temperature values of the DESs ranged between 0.4 and 2.4, with the highest inhibition to lowest inhibition order being TEAB:Glycerol > TEAB:MEG > TEAAC:Glycerol > TEAAC:MEG. A comparison of the DES with conventional Thermodynamic Hydrate Inhibitors (THIs) showed that studied Deep Eutectic Solvents had better gas hydrate inhibition. The results proved that DES has the potential to be one of the promising alternatives in gas hydrate inhibition.

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