Calculation of the relative acidities and oxidation potentials of para-substituted phenols. A model for α-tocopherol in solution

2007 ◽  
Vol 5 (11) ◽  
pp. 1739-1743 ◽  
Author(s):  
Nakul K. Singh ◽  
Majeed S. Shaik ◽  
Patrick J. O'Malley ◽  
Paul L. A. Popelier
Keyword(s):  
Substituted Phenols ◽  
Oxidation Potentials

scholarly journals Coexistence of Substituted Phenols Reduces the Fouling Ability of Phenol in Non-aqueous Solvents

2021 ◽  
Author(s):  
László Kiss
Keyword(s):  
Phenol Concentration ◽  
Aqueous Systems ◽  
Substituted Phenols ◽  
Oxidation Potentials

The electrooxidation of phenol showed different rate of deactivation by varying the concentration of substituted phenols (4-chlorophenol, 4-methoxyphenol, 4-tert-butylphenol). This was due to the more favourable solubility properties of the product copolymers compared with poly(phenyleneoxide) the product which forms when only unsubstituted phenol is present. The nature of substituent, switching potential and oxidation potentials of the studied phenols were significant in prevention of electrode fouling. The best reproducibility could be achived upon addition of 4-chlorophenol. This offered a possibility for estimation of phenol concentration in non-aqueous systems.

scholarly journals Oxidation potentials of phenols and anilines: correlation analysis of electrochemical and theoretical values

2017 ◽  
Vol 19 (3) ◽  
pp. 339-349 ◽  
Author(s):  
Ania S. Pavitt ◽  
Eric J. Bylaska ◽  
Paul G. Tratnyek
Keyword(s):  
Correlation Analysis ◽  
Kinetic Data ◽  
Manganese Oxides ◽  
Substituted Phenols ◽  
Oxidation Potentials

New experimental and theoretical oxidation potentials for substituted phenols and anilines give improved correlations to kinetic data with manganese oxides.

Separation of close boiling substituted phenols by dissociation extraction

1981 ◽  
Vol 31 (1) ◽  
pp. 279-284 ◽  
Author(s):  
Vishwas V. Wadekar ◽  
Man Mohan Sharma
Keyword(s):  
Substituted Phenols

Quantitative Structure-Property Relationship (QSPR) Study of the Hydrophobicity of Phenols and 2-(Aryloxy-a-acetyl)-phenoxathiin Derivatives

2008 ◽  
Vol 59 (11) ◽  
Author(s):  
Adrian Beteringhe ◽  
Ana Cristina Radutiu ◽  
Titus Constantinescu ◽  
Luminita Patron ◽  
Alexandru T. Balaban
Keyword(s):  
Water Solubility ◽  
Molecular Descriptors ◽  
Log P ◽  
Structure Property ◽  
Substituted Phenols ◽  
Reverse Phase ◽  
Aromaticity Index ◽  
Structure Property Relationship ◽  
Layer Chromatography ◽  
Energy Of Formation

In a preceding study, the molecular hydrophobicity (RM0) was determined experimentally from reverse-phase thin-layer chromatography data for several substituted phenols and 2-(aryloxy-a-acetyl)-phenoxathiin derivatives, obtained from the corresponding phenoxides and 2-(a-bromoacetyl)-phenoxathiin. QSPR correlations for RM0 were explored using four calculated molecular descriptors: the water solubility parameter (log Sw), log P, the Gibbs energy of formation (DGf), and the aromaticity index (HOMA). Triparametric correlations do not improve substantially the biparametric correlation of RM0 in terms of log Sw and HOMA.

Effects of Doping on the Electrochemical and Electrical Properties of Poly(2,5-di(2-thienyl)pyrrole)

1999 ◽  
Vol 64 (8) ◽  
pp. 1357-1368 ◽  
Author(s):  
Enric Brillas ◽  
José Carrasco ◽  
Ramon Oliver ◽  
Francesc Estrany ◽  
Víctor Ruiz
Keyword(s):  
Mass Spectrometry ◽  
Fast Atom Bombardment ◽  
Oxidation Potential ◽  
Ethanolic Solution ◽  
Pt Electrode ◽  
Reversible Process ◽  
Oxidation Potentials ◽  
Lower Productivity ◽  
Polymeric Chains ◽  
Linear Molecules

The electropolymerization of 2,5-di(2-(thienyl)pyrrole) (SNS) on a Pt electrode from ethanolic solution with LiClO4 or LiCl as electrolyte has been studied by cyclic voltammetry (CV) and chronoamperometry (CA). In both media, a quasi-reversible process has been indicated by CV, reversing the scan at low oxidation potentials. Under these conditions, reducible positive charges formed in both oxidized polymers are compensated by the entrance of anions from solution. Elemental analysis reveals that polymers generated at a low oxidation potential by CA contain a 21.03% (w/w) of ClO4- or a 9.56% (w/w) of Cl-. The poly(SNS) doped with Cl- presents higher proportion of reducible positive charges, higher polymerization charge and lower productivity. A much higher electrical conductivity, however, has been found for the poly(SNS) doped with ClO4-. Both polymers are soluble in DMSO, acetone and methanol. The dimer, trimer, tetramer and pentamer have been detected as soluble and neutral linear oligomers by mass spectrometry-fast atom bombardment. The analysis of polymers by infrared spectroscopy confirms the predominant formation of linear molecules with α-α linkages between monomeric units. A condensation mechanism involving one-electron oxidation of all electrogenerated linear and neutral polymeric chains is proposed to explain the SNS electropolymerization.

Redox Potential - (Electronic) Structure Relationships in 18- and 17-Electron Mononitrile (or Monocarbonyl) Diphosphine Complexes of Re and Fe

2001 ◽  
Vol 66 (1) ◽  
pp. 139-154 ◽  
Author(s):  
M. Fátima C. Guedes Da Silva ◽  
Luísa M. D. R. S. Martins ◽  
João J. R. Fraústo Da Silva ◽  
Armando J. L. Pombeiro
Keyword(s):  
Cyclic Voltammetry ◽  
Electronic Structure ◽  
Binding Sites ◽  
Closed Shell ◽  
Carbonyl Complexes ◽  
Metal Centre ◽  
Pt Electrode ◽  
Metal Site ◽  
Oxidation Potentials ◽  
First Time

The organonitrile or carbonyl complexes cis-[ReCl(RCN)(dppe)2] (1) (R = 4-Et2NC6H4 (1a), 4-MeOC6H4 (1b), 4-MeC6H4 (1c), C6H5 (1d), 4-FC6H4 (1e), 4-ClC6H4 (1f), 4-O2NC6H4 (1g), 4-ClC6H4CH2 (1h), t-Bu (1i); dppe = Ph2PCH2CH2PPh2), or cis-[ReCl(CO)(dppe)2] (2), as well as trans-[FeBr(RCN)(depe)2]BF4 (3) (R = 4-MeOC6H4 (3a), 4-MeC6H4 (3b), C6H5 (3c), 4-FC6H4 (3d), 4-O2NC6H4 (3e), Me (3f), Et (3g), 4-MeOC6H4CH2 (3h); depe = Et2PCH2CH2PEt2), novel trans-[FeBr(CO)(depe)2]BF4 (4) and trans-[FeBr2(depe)2] (5) undergo, as revealed by cyclic voltammetry at a Pt-electrode and in aprotic non-aqueous medium, two consecutive reversible or partly reversible one-electron oxidations assigned as ReI → ReII → ReIII or FeII → FeIII → FeIV. The corresponding values of the oxidation potentials IE1/2ox and IIE1/2ox (waves I and II, respectively) correlate with the Pickett's and Lever's electrochemical ligand and metal site parameters. This allows to estimate these parameters for the various nitrile ligands, depe and binding sites (for the first time for a FeIII/IV couple). The electrochemical ligand parameter show dependence on the "electron-richness" of the metal centre. The values of IE1/2ox for the ReI complexes provide some supporting for a curved overall relationship with the sum of Lever's electrochemical ligand parameter. The Pickett parametrization for closed-shell complexes is extended now also to 17-electron complexes, i.e. with the 15-electron ReII and FeIII centres in cis-{[ReCl(dppe)2]}+ and trans-{FeBr(depe)2}2+, respectively.

scholarly journals Methane production and oxidation potentials along a fen‐bog gradient from southern boreal to subarctic peatlands in Finland

2021 ◽  
Author(s):  
Hui Zhang ◽  
Eeva‐Stiina Tuittila ◽  
Aino Korrensalo ◽  
Anna M. Laine ◽  
Salli Uljas ◽  
...  
Keyword(s):  
Methane Production ◽  
Oxidation Potentials
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