ChemInform Abstract: USE OF KINETIC ISOTOPE EFFECTS IN MECHANISM STUDIES. EFFECT OF AN INTERNAL RETURN MECHANISM ON THE ARRHENIUS BEHAVIOR OF PRIMARY HYDROGEN ISOTOPE EFFECTS

1980 ◽  
Vol 11 (50) ◽  
Author(s):  
H. F. KOCH ◽  
D. B. DAHLBERG
Keyword(s):  
Hydrogen Isotope ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Arrhenius Behavior ◽  
Kinetic Isotope

Kinetic hydrogen isotope effects in the ionization of some carbon acids

1970 ◽  
Vol 318 (1535) ◽  
pp. 421-440 ◽  
Keyword(s):  
Aqueous Solutions ◽  
Rate Constants ◽  
Hydrogen Isotope ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Kinetic Isotope ◽  
Pyridine Bases ◽  
Carbon Acids ◽  
Ethyl Nitroacetate ◽  
Basic Strength

Rate constants in aqueous solutions are reported for proton and deuteron abstraction by a variety of bases from tricarbomethoxymethane, the propan-2-one-1-sulphonate ion, 2-acetylcyclohexanone and ethyl nitroacetate. The rates of ionization were measured by using bromine or iodine as scavengers to remove the anions, and, for ethyl nitroacetate by direct observation of the rate of appearance of the anion. The kinetic isotope effects vary from k H / k D = 2.5 to k H / k D = 10.3, and confirm the regularities previously found (Bell & Crooks 1965; Bell & Goodall 1966). In particular, the results for the reaction of ethyl nitro-acetate with nine bases show clearly that with increasing basic strength the isotope effect passes through a well-marked maximum. Sterically hindered pyridine bases give rise to abnormally high isotope effects, probably attributable to increased tunnel corrections.

scholarly journals How coverage influences thermodynamic and kinetic isotope effects for H2/D2 dissociative adsorption on transition metals

2020 ◽  
Vol 10 (3) ◽  
pp. 671-689 ◽  
Author(s):  
Benjamin W. J. Chen ◽  
Manos Mavrikakis
Keyword(s):  
Transition Metals ◽  
Reaction Mechanisms ◽  
Hydrogen Isotope ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Dissociative Adsorption ◽  
Kinetic Isotope

Hydrogen isotope effects are influenced by adsorbate coverage: at high coverages, isotope effects are lower than at low coverages. This helps to rationalize observed isotope effects, allowing more precise elucidation of reaction mechanisms.

Sign in / Sign up

Export Citation Format

Share Document