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  • 1
    Electronic Resource
    Electronic Resource
    On the decarboxylation of oxalic acid in solutions (1978)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 10 (1978), S. 669-675 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The first-order kinetics and hydrogen kinetic isotope effect of the decarboxylation of oxalic acid in acetophenone were studied in the temperature range of 109.6°-150.0°C. The rate constants, activation parameters, and hydrogen kinetic isotope effect were calculated. Detailed comparison and discussion of the results were made with the data reported in the literature. Kinetic isotope effects and solvent effects on rates should be considered similar in mechanistic and/or theoretical studies in the sense that kinetic isotope effects result from a small perturbation of the reaction coordinate, while the solvent effect causes a general overall variation on the potential energy surface (thereby resulting in a change in the reaction coordinate).
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550100703
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  • 2
    Electronic Resource
    Electronic Resource
    Kinetics and mechanism of the pyrolysis of pentachloroethane (1975)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 7 (1975), S. 331-339 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rate of the inhibited pyrolysis of pentachloroethane was studiedover the temperature range of 820 to 865°K using the toluene-carrier technique in a stirred-flow reactor. The pyrolysis rate was found to be first order in reactant, and the rate constant is described by k=1011.6±0.7 exp [(-48,200±2600)/RT] sec-1. An increase by a factor of 6.6 in the surface/volume of the reactor had a negligible effect on the rate. This observation, in addition to a reevaluation of earlier kinetic data for the pyrolysis of pentachloroethane, lead to the following conclusions concerning the pyrolysis mechanism. The initiation and termination as well as the propagation reactions were homogeneous, the termination involved both Cl and C2Cl5 radicals (crosstermination), and autocatalysis was caused by interaction between chlorine and pentachloroethane rather than by dissociation of molecular chlorine.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550070303
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  • 3
    Electronic Resource
    Electronic Resource
    The mechanism of methanol formation and other reactions following formaldehyde adsorption on Ni(110) (1978)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 10 (1978), S. 871-882 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The adsorption/desorption and reactive behavior of formaldehyde was studied on clean single-crystal Ni(110) at adsorption temperatures down to 200 °K. For low exposures of the surface to formaldehyde, hydrogen and CO binding states were populated due to decomposition of the molecule upon adsorption. Higher exposures gave rise to a decomposition-limited hydrogen peak exhibiting an activation energy of 20 kcal/gmol and an apparent frequency factor of 1014 sec-1. At initial coverages of H2CO exceeding about 0.5, monolayer methanol was observed to form. The formation of methanol involved a hydrogen atom transfer between two adsorbed H2CO molecules and did not occur totally via surface hydrogen. Self-oxidation to form CO2 was also observed. The surface exhibited reaction heterogeneity, and the surface reactivity was observed to depend on the temperature of adsorption of reactants, suggesting strong adsorbate-induced surface “reconstruction.”
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550100807
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  • 4
    Electronic Resource
    Electronic Resource
    Gas-phase pyrolysis of 2,2,3,3-tetramethylbutane using a wall-less reactor (1978)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 10 (1978), S. 1245-1257 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The pyrolysis of 2,2,3,3-tetramethylbutane (TMB) has been studied using the wall-less reactor. Under homogeneous conditions up to 670°C, the activation energy is 43.2 kcal/mol and log A is 10.70. The products are 2-methylpropene, hydrogen, propene, 2-methyl-2-butene, ethane, ethene, methane, neopentane, and 2,3-dimethyl-2-butene in order of abundance. Addition of toluene, cyclopentadiene, or nitrous oxide to the system increases both the activation energy and the A factor; whereas oxygen decreases both the activation energy and the A factor. Incorporation of stainless-steel rods to provide surface has only a modest effect upon the rate. In view of this evidence, it appears that the homogeneous pyrolysis of TMB at higher pressures is a chain reaction under the described conditions.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550101207
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  • 5
    Electronic Resource
    Electronic Resource
    Kinetics and mechanism of hydrogen-oxygen difluoride reaction in magnesium (1978)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 10 (1978), S. 773-781 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the H2-OF2 reaction was studied in the temperature range of 160°-310°C at 1 atm total pressure in a magnesium stirred-flow reactor. Initial concentration ranges were 1/2-1/2 mol·% OF2, 3/16-5 mol·% H2, and 1/4-5.0 mol·% O2; helium was used as the diluent. When the reactants were in a mole ratio of 3/2 (H2/OF2), the rate of disappearance of H2 was 1.5 times that of OF2, consistent with the previously reported stoichiometry. The rate of disappearance of OF2 was strongly influenced by OF2 concentration, weakly influenced by H2 concentration, and inhibited by the oxygen formed in the reaction. An increase in the surface area did not produce a significant change in the rate of reaction. These concentration dependencies led to a proposed ten-step mechanism from which was derived the following rate equation: \documentclass{article}\pagestyle{empty}\begin{document}$$ \frac{{- d(\rm {OF}_2)}}{{dt}} = \frac{{k_0 (\rm {OF}_2)^2}}{{(\rm {O}_2)^{1/2}}}\left(1 + \frac{{\alpha (\rm {OF}_2)}}{{\alpha (\rm {OF}_2) + \beta (\rm {H}_2)}}\right) $$\end{document} where k0 is a complex combination of elementary rate constants and α and β are elementary rate constants. An Arrhenius treatment of k0 gave \documentclass{article}\pagestyle{empty}\begin{document}$$ k_0 = 10^{8.41 \pm 0.24} \exp (- 17,300 \pm 500/RT)(\rm {l}./\rm {mol})^{1/2} /\sec $$\end{document}These experimental Arrhenius parameters are lower than those predicted from reported and estimated elementary rate constants. The possibility of heterogeneous contributions is discussed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550100710
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