Hydrogen‐Deuterium Kinetic Isotope Effect at Very High Temperature

1962 ◽  
Vol 36 (2) ◽  
pp. 463-468 ◽  
Author(s):  
Harold S. Johnston ◽  
Eugene Tschuikow‐Roux
1984 ◽  
Vol 62 (5) ◽  
pp. 899-906 ◽  
Author(s):  
Jan Niedzielski ◽  
T. Yano ◽  
E. Tschuikow-Roux

The abstraction of hydrogen/deuterium from CH3CHDCl by ground state chlorine atoms produced photolytically from Cl2 has been investigated at temperatures betwen 280 and 368 K. The relative rates for the internal competition[Formula: see text]are found to conform to an Arrhenius rate law:[Formula: see text]These data, taken together with the external competition results for the C2H5Cl/CH3CHDCl system, in conjunction with the competitive results using CH4 as a primary reference, have yielded the rate constants (cm3 s−1):[Formula: see text]The relatively weak primary kinetic isotope effect, kH/kD, decreases with increasing temperature from 1,855 at 280 K to 1.66 at 365 K. The results are compared with those obtained based on the BEBO method. While both the trend and the magnitude of the kinetic isotope effect are satisfactorily predicted, the activation energy is not.


Molecules ◽  
2019 ◽  
Vol 24 (23) ◽  
pp. 4359 ◽  
Author(s):  
Mateusz Z. Brela ◽  
Alja Prah ◽  
Marek Boczar ◽  
Jernej Stare ◽  
Janez Mavri

Monoamine oxidase A (MAO A) is a well-known enzyme responsible for the oxidative deamination of several important monoaminergic neurotransmitters. The rate-limiting step of amine decomposition is hydride anion transfer from the substrate α–CH2 group to the N5 atom of the flavin cofactor moiety. In this work, we focus on MAO A-catalyzed benzylamine decomposition in order to elucidate nuclear quantum effects through the calculation of the hydrogen/deuterium (H/D) kinetic isotope effect. The rate-limiting step of the reaction was simulated using a multiscale approach at the empirical valence bond (EVB) level. We applied path integral quantization using the quantum classical path method (QCP) for the substrate benzylamine as well as the MAO cofactor flavin adenine dinucleotide. The calculated H/D kinetic isotope effect of 6.5 ± 1.4 is in reasonable agreement with the available experimental values.


1977 ◽  
Vol 32 (3-4) ◽  
pp. 343-344 ◽  
Author(s):  
H. J. Bauer ◽  
J. Grosselfinger ◽  
M. Zwick

Abstract The cathodic charging with H/D of a NiCu alloy containing 30 At.-% Cu followed by magnetic measurements indicates that D penetrates faster into the alloy than H.


1977 ◽  
Vol 55 (22) ◽  
pp. 3951-3954 ◽  
Author(s):  
Robert J. Crawford ◽  
Stuart Lutener ◽  
Hirokazu Tokunaga

The thermal decarbonylation of 2,2-dimethyl-3-butenal is shown to be an intramolecular extrusion of carbon monoxide concerted with the transfer of hydrogen (deuterium) to the γ-position. The reaction displays a kinetic isotope effect of 2.8 (at 296.9 °C) and follows first order kinetics (Ea = 44.2 ± 0.2 kcal mol−1, log A = 13.4 ± 0.3).


1983 ◽  
Vol 14 (43) ◽  
Author(s):  
P. F. M. T. VAN NISSELROOIJ ◽  
J. A. M. LUTTIKHOLT ◽  
R. Z. C. VAN MEERTEN ◽  
M. H. J. M. DE CROON ◽  
J. W. E. COENEN

1983 ◽  
Vol 6 (3) ◽  
pp. 271-281 ◽  
Author(s):  
P.F.M.T. van Nisselrooij ◽  
J.A.M. Luttikholt ◽  
R.Z.C. van Meerten ◽  
M.H.J.M. de Croon ◽  
J.W.E. Coenen

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