Results 161 to 170 of about 21,289 (213)

Kinetic isotope effect in hydrolysis of bisdiazoketones

Bulletin of the Academy of Sciences of the USSR Division of Chemical Science, 1984
In the hydrolysis of bisdiazoketones in aqueous HClO4 solutions the step of protonating the starting compounds is not the limiting step; differences in the reactivity of the disdiazoketones is apparently related to the variable decomposition rate of the formed diazonium ions.
L. I. Kirkovskii, V. G. Kartsev, A. M. Sipyagin   +2 more
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Equilibrium and kinetic isotope effects

Berichte der Bunsengesellschaft für physikalische Chemie, 1972
AbstractThe equilibrium distribution effects of deuterium and of tritium between liquid water, hydrogen gas and palladium hydride differ from one another in a characteristic manner. They are discussed in terms of zero point energies.Direct measurements of the deuterium distribution between liquid water and palladium hydride yielded an uncommonly high ...
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Kinetic-isotope effects in thermal explosions

Thermochimica Acta, 1982
Abstract Kinetic-isotope effects can be used to detect the specific functional groups involved in the elementary reactions of complex explosives decomposition processes. Isothermal kinetics methods must be used to correlate component reactions with specific reaction regimes.
M. H. Ebinger, J. L. Janney, R.N. Rogers
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Interpretation of Transient-State Kinetic Isotope Effects

Biochemistry, 1996
In contrast to steady-state kinetic isotope effects (KIE's), transient-state KIE's are dependent on both time and signal source. We developed a theory which predicts the behavior of transient-state KIE's, permits the calculation of the intrinsic KIE, and makes possible the assignment of various optical signals to either pre- or post-hydride transfer ...
Harvey F. Fisher, Swapan K. Saha
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Temperature Dependences of Kinetic Isotope Effects

The Journal of Chemical Physics, 1971
Model-reaction calculations are used to investigate the expected incidence of temperature-dependence anomalies produced by the harmonic-vibrational contributions to kinetic isotope effects. These “anomalies” are defined as deviations from a smooth-monotonic log–log plot of isotopic rate-constant ratio vs temperature. Such deviations include inflections,
P. Christian Vogel, Marvin J. Stern
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Kinetic isotope effect in the chlorination of methane

Reaction Kinetics and Catalysis Letters, 1975
The ratio of the rate constants has been measured for the reaction of atomic chlorine with CH4 and CD4 within the temperature range 163–613 K. At low temperatures (163–300 K) the ratio is 2.2 exp (1180/RT). The pre-exponential factor of 2.2 agrees with that calculated by transition state theory.
V. N. Panfilov, V. P. Strunin, N. K. Serdyuk, E. N. Chesnokov   +3 more
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Quantum effects and isotope effects in chemical kinetics

International Journal of Chemical Kinetics, 1979
AbstractThe relations of quantum and kinetic isotope effects are investigated using the exact quantum corrections to the collision and activated complex theories. The latter are computed for the collinear three‐atomic reaction H2+ H → H + H2and the related isotopic reactions using realistic potential energy surfaces.
S. G. Christov, M. Parlapanski
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The kinetic isotope effect in the photochlorination of methane

Tetrahedron, 1963
The kinetic isotope effect for the photochemically initiated chlorination of methane-d/sub 2/ was determined. The value is k /sub H//k/sub D/ = 12.1 at 0 deg C, and the variation with temperature is given by k/sub H//k/sub D/= 1.09 exp (1300/RT). The results are considered in terms of a semiempirical potential energy surface, and the general subject of
K.B. Wiberg, E.L. Motell
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Influence of Substituents on Kinetic Isotope Effects

Journal of the American Chemical Society, 1996
The E2 reactions of methyl- and fluoro-substituted ethyl chlorides with CH3-, NH2-, OH-, F-, SH-, and Cl- have been investigated at the MP2/6-31+G(d) level of theory for probing whether kinetic isotope effects are related to the geometry of the transition stucture.
Frank Jensen, and Sanne S. Glad, Peter Aa. Nielsen   +2 more
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Kinetic Isotope Effect in the Bromination of Dimethylaniline

Nature, 1959
THE recent account by Shilov and Weinstein1 of a kinetic isotope effect in the iodination of some aromatic amines prompts us to report the observation of a similar effect in the bromination of dimethylaniline.
S. F. Mason, P. G. Farrell
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