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  • 1995-1999  (4)
  • 1960-1964
  • 1996  (4)
  • 1
    ISSN: 1434-4475
    Keywords: Substituted phenethyl alcohols ; Oxidation ; Chloramine-T ; Kinetics ; Linear free energy relationships
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Kinetik der Oxidation von sechsp-substituierten Phenethylalkoholen (PEA), R=−H, −Cl, −Br, −OCH3 und NO2) mit Natrium-N-chlor-p-toluolsulfonamid (Chloramin-T,CAT) in Gegenwart von HCl bei 35°C wurde untersucht. Die Reaktionsgeschwindigkeit ist in bezug auf [CAT]0 und [H+]0 ester und hinsichtlich [PEA]0 und [Cl]0 gebrochener Ordnung. Variation der Ionenstärke, Zusatz von Reaktionsprodukt oder Toluolsulfonamid und Variation der Dielektrizitätskonstante des Mediums haben keinen Einfluß auf die Reaktionsgeschwindigkeit Der Lösungsmittel-Isotopeneffekt $$k_{H_2 0}^\prime /k_{D_2 0}^\prime $$ beläuft sich auf etwa 0.90. Die Protonenbilanz wurde in H2O-D2O Mischungen untersucht. Die Geschwindigkeiten korrelieren zufriedenstellend nach derHammettschen Beziehung. Die Reaktionskonstante wurde mit ρ=−3.3 für elektronenabgebende und ρ=−0.25 für elektronenanziehende Substituenten bei 35°C bestimmt. Die Aktivierungsparameter ΔH #, ΔG #, ΔG # und logA wurden abgeleitet; ΔH # und ΔS # korrelieren linear, und eine isokinetische Beziehung mit β=166.7K weist auf die Entropie als kontrollierenden Faktor hin.
    Notes: Summary The kinetics of the oxidation of sixp-substituted phenethyl alcohols (PEA, R=−H, −Cl, −Br, −CH3, −OCH3, and -NO2) by sodium-N-chloro-p-toluene sulfonamide (chloramine-T,CAT) in the presence of HCl was studied at 35°C. The rate shows a first order dependence on [CAT]0 and [H+]0 and a fractional order in [PEA]0 and [Cl−]0. Ionic strength variations, addition of reaction product toluene sulfonamide, and variation of the dielectric constant of the medium have no effect on the rate. The solvent isotope effect $$k_{H_2 0}^\prime /k_{D_2 0}^\prime $$ amounts to about 0.90. Proton inventory studies have been made in H2O-D2O mixtures. The rates correlate satisfactorily withHammett's relationship. The reaction constant ρ was −3.3 for electron releasing substituents and −0.25 for electron withdrawing groups at 35°C. The activation parameters ΔH #, ΔS #, ΔG #, and logA were derived. ΔH # and ΔS # are linearly related, and an isokinetic relationship is observed with β=166.7K, indicating entropy as a controlling factor.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 9 (1996), S. 279-286 
    ISSN: 0894-3230
    Keywords: Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The kinetics of the oxidation of six substituted phenethyl alcohols by sodium N-chlorobenzenesulphonamide or chloramine-B (CAB) in the presence of HCl was studied at 35°C. The rate shows a first order dependence on [CAB]0 and [H+] and is of fractional order in [PEA]0 and [Cl-]. Ionic strength variations, addition of the reaction product of benzenesulphonamide and variation of the dielectric constant of the medium have no effect on the rate. The solvent isotope effect k1H2O/k1D2O ≅ 0·78. Proton inventory studies were made in H2O-D2O mixtures. The rates correlate satisfactorily with Hammett's LFER. The reaction constant ρ was -3·5 for electron-releasing substituents and -0·30 for electron withdrawing groups at 35°C. Activation parameters ΔH
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 9 (1996), S. 439-446 
    ISSN: 0894-3230
    Keywords: Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The kinetics of the oxidation of six substituted phenethyl alcohols by sodium N-chlorobenzenesulphonamide or chloramine-B (CAB) in the presence of HCl was studied at 35°C. The rate shows a first-order dependence on [CAB]0 and [H+] and is fractional order in [PEA]0 and [Cl-]. Ionic strength variations, addition of reaction product of benzenesulphonamide and variation of the dielectric constant of the medium have no effect on the rate. The solvent isotope effect k1H2O/k1D2O ≅ 0·78. Proton inventory studies were made in H2O-D2O mixtures. The rates correlate satisfactorily with the Hammett linear free energy relationship. The reaction constant ρ was -3 · 5 for electron-releasing and -0·30 for electron-withdrawing groups at 35°C. Activation parameters ΔH*, ΔS*, ΔG* and log A were calculated for the reaction. An isokinetic relationship is observed with β = 338 K, indicating enthalpy as a controlling factor.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 28 (1996), S. 265-274 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of oxidation of the title substrates by sodium N-haloarylsulfonamides (or ary-N-haloamines), chloramine-T (CAT), bromamine-T (BAT), chloramine-B (CAB), and bromamine-B (BAB), catalyzed by osmium(VIII) in alkaline medium has been studied at 30°C. The corresponding oxindoles and arylsulfonamides have been characterized as reaction products. The reaction rate shows a first-order dependence each on |indole|0 and |oxidant|0, a fractional-order on |Os(VIII)|, and an inverse first-order on |OH-|. Addition of arylsulfon-amide, chloride and bromide, and variation of ionic strength of the medium have no effect on the reaction rate. There is a negative effect of dielectric constant of the solvent. Activation parameters have been calculated from the Arrhenius and Eyring plots. Hammett correlation of substituent effects indicates an LFE relationship with ρ = -1.0, showing the formation of an electron deficient transition state. From enthalpy-entropy relationships and Exner correlations, the isokinetic temperatures (333 K and 326 K) have been determined for the reactions of CAT and BAT, respectively. Proton inventory studies in H2O-D2O mixtures have shown the involvement of a single exchangeable proton of OH- ion in the transition state. A mechanism consistent with the observed kinetics has been proposed. © 1996 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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