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1Author    Joachim Staufif, Wolfgang JaeschkeRequires cookie*
 Title    Chemilumineszenz der S02-Oxidation Chemiluminescence of SO2-Oxidation  
 Abstract    The reactions of diluted aqueous solutions of SO2 resp. HSO3-ions with MJ1O4-or Ce 4+ ions in the pH range 1-4 produce chemiluminescence in the spectral region of 450-600 nm. Measurements of the time course of the light emission and their simulation on an analog computer led to a reaction scheme in which a recombination product of primarily formed HSO3 radicals -of a lifetime of about 1 second -appears as precursor of electronically excited SO2 molecules. The participation of singlet oxygen can be excluded because at least the reaction with Ce 4+ ions proceeds also in the absence of oxygen. 
  Reference    Z. Naturforsch. 33b, 293—299 (1978); eingegangen am 30. September/12. Dezember 1977 
  Published    1978 
  Keywords    Sulfur Dioxide, Oxidation, Chemiluminescence, Reaction Kinetics, Analysis 
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 TEI-XML for    default:Reihe_B/33/ZNB-1978-33b-0293.pdf 
 Identifier    ZNB-1978-33b-0293 
 Volume    33 
2Author    Cornelia Neidl, Joachim StauffRequires cookie*
 Title    Spectra and Decay Kinetics of Diadamantyl-Dioxetane Chemiluminescence  
 Abstract    The thermal decomposition of 1,2-diadamantyldioxetane was studied by kinetic and spectroscopic methods. Spectra of the chemiluminescence emitted during the thermally induced decomposition of 1,2-diadamantyldioxetane, tetramethyldioxetane and tri-methyldioxetane were obtained and the influence of quenchers and radical-scavengers, and the presence of "heavy atoms" in the surrounding of the emitting species was investigated. The kinetics of the decay mechanism was followed by measuring the time dependence of the chemiluminescence. The influence of radical-scavengers, quenchers and "external heavy atoms" on the kinetics was assessed. Experimental results were discussed in terms of a biradical decay mechanism. 
  Reference    Z. Naturforsch. 33b, 763—769 (1978); received January 26 1978 
  Published    1978 
  Keywords    Chemiluminescence, Dioxetanes, Reaction Kinetics, Spectra, Biradicals 
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 TEI-XML for    default:Reihe_B/33/ZNB-1978-33b-0763.pdf 
 Identifier    ZNB-1978-33b-0763 
 Volume    33 
3Author    R. Om, G., EligiuszS. Erafin, JanuszM. AzurRequires cookie*
 Title    The Kinetics of the Reaction of Thiocyanate and Nitrite Ions with Orconectes limosus Oxyhemocyanin  
 Abstract    The time course of the reaction of oxyhemocyanin from the arthropod Orconectes limosus with SCN" and N 0 2 " was investigated. After addition of one of these anions to oxyhemocyanin solu­ tion an exponential decay of A 340 was found, indicating a removal of oxygen from the active site. The order of reaction with respect to ligand was about 3 for thiocyanate and about 1 for nitrite. On this basis, a possible arrangement of ligands in the active site has been proposed. The final product of reaction with SCN" yielded a mononuclear copper EPR spectrum while the reaction product with N 07 gave a characteristic spectrum of two coupled Cu2+ ions. It was possible to remove the ligands from the active site by dialysis. The reaction patterns showed distinct changes in a narrow pH range, 5.3—6.5. A possible effect of structural alterations of the protein moiety on the course of the reaction of oxyhemocyanin with ligands is suggested. 
  Reference    Z. Naturforsch. 40c, 677—681 (1985); received February 4 1985 
  Published    1985 
  Keywords    Hemocyanin, Reaction Kinetics, Copper, Electron Paramagnetic Resonance 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0677.pdf 
 Identifier    ZNC-1985-40c-0677 
 Volume    40 
4Author    Thomas Rausch, Frieder Hofmann, Willy HilgenbergRequires cookie*
 Title    Kinetics of Oxidation of Tryptophan by Sodium Hypochlorite  
 Abstract    The oxidation of tryptophan to 3-indoleacetaldehyde with sodium hypochlorite was investigated with 14 C labelled DL-tryptophan. The reaction was performed under pseudo first order conditions. From the pH dependence of the reaction it was concluded that only the unprotonated tryptophan is converted to the aldehyde. The activation energy is 35 ± 2.2 (SE) kJ x mol -1 as derived from the Arrhenius plot. Variing the pH between 8.5 and 11.0 and the temperature in the range from 298 K to 318 K did not alter the selectivity of the reaction as confirmed by TLC of the product (purity > 90%). A possible reaction mechanism is proposed. 
  Reference    Z. Naturforsch. 36b, 359—361 (1981); received September 12 1980 
  Published    1981 
  Keywords    Tryptophan, Indoleacetaldehyde, Amino Acid Oxidation, Sodium Hypochlorite, Reaction Kinetics 
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 TEI-XML for    default:Reihe_B/36/ZNB-1981-36b-0359.pdf 
 Identifier    ZNB-1981-36b-0359 
 Volume    36 
5Author    Alicja Piesiak, M. An, Nien Schuchmann, Henryk Zegota, Clemens Von SonntagRequires cookie*
 Title    ß-Hydroxyethylperoxyl Radicals: A Study of the y-Radiolysis and Pulse Radiolysis of Ethylene in Oxygenated Aqueous Solutions  
 Abstract    Hydroxyl radicals (and H atom s) generated in the radiolysis of N20-co n tain in g w ater add to ethylene forming /3-hydroxyethyl radicals (and ethyl radicals). In the presence of oxygen these are converted into the corresponding peroxyl radicals which decay bim olecularly (2 k — 2 x 108 M ~'s-1) as m easured by pulse radiolysis. The m ajor products (G values in brackets) are glycolaldehyde (3.3), form aldehyde (1.6), ethylene glycol (0.8), acetaldehyde (0.5), organic peroxidic m aterial (0.5), and hydrogen peroxide (2.4) (dose rate 0.26 Gy s-1, pH 5.6). A m aterial balance has been obtained with respect to the primary w ater radicals (6.0) and oxygen uptake (4.8). The products and their yields can be accounted for if in the rate determ ining step atetro x id e is form ed which decomposes via three m ajor pathways leading to; (i) H 20 2 and two m olecules of glycolaldehyde (ca. 45%), (ii) 0 2, glycolaldehyde and ethylene glycol (ca. 30%), and (iii) 0 2, two molecules of form aldehyde and two C H 2OH radicals (ca. 15%). A 1,2-H shift of interm ediate oxyl radicals is unim portant in this system. 
  Reference    Z. Naturforsch. 39b, 1262—1267 (1984); received March 5 1984 
  Published    1984 
  Keywords    Peroxyl Radicals, Oxyl Radicals, Pulse Radiolysis, Ethylene, Reaction Kinetics 
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 TEI-XML for    default:Reihe_B/39/ZNB-1984-39b-1262.pdf 
 Identifier    ZNB-1984-39b-1262 
 Volume    39 
6Author    WilhelmF M Aier, FeliciaA. EtzkornbRequires cookie*
 Title    Hinweise zur thermodynamischen Kontrolle von relativen Hydriergeschwindigkeiten an Platin Indications to a Thermodynamic Control of the Relative Rate of Hydrogenation on Platinum  
 Abstract    The relative rate o f hydrogenation o f various alkenes has been determined by competition experiments in the gas phase on platinum films. Despite big structural differences in the al­ kenes there is a good correlation o f the relative rate o f hydrogenation with the calculated heat o f hydrogen atom addition to the double bond, indicating thermodynamic control o f this reac­ tion. 
  Reference    Z. Naturforsch. 47b, 175—178 (1992); eingegangen am 9. Juli/9. September 1991 
  Published    1992 
  Keywords    Heterogeneous Catalysis, Alkene Hydrogenation, Platinum Films, Gas Phase, Reaction Kinetics 
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 TEI-XML for    default:Reihe_B/47/ZNB-1992-47b-0175.pdf 
 Identifier    ZNB-1992-47b-0175 
 Volume    47