ChemInform Abstract: ACIDITY OF HYDROCARBONS PART 47, PRIMARY KINETIC ISOTOPE EFFECTS AND INTERNAL RETURN IN HYDROGEN ISOTOPE EXCHANGE OF TOLUENE AND TRIPHENYLMETHANE WITH LITHIUM CYCLOHEXYLAMIDE

1973 ◽  
Vol 4 (35) ◽  
pp. no-no
Author(s):  
A. JUN. STREITWIESER ◽  
P. H. OWENS ◽  
G. SONNICHSEN ◽  
W. K. SMITH ◽  
G. R. ZIEGLER ◽  
...  
Keyword(s):  
Hydrogen Isotope ◽  
Isotope Exchange ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Hydrogen Isotope Exchange ◽  
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.

Isotope Effects in Diffusions of H and D in Hydrogen Isotope Exchange in Oxide Ceramics

2002 ◽  
Vol 39 (4) ◽  
pp. 359-362 ◽  
Author(s):  
Kazuo SODA ◽  
Emi IIZUKA ◽  
Bun TSUCHIYA ◽  
Kenji MORITA ◽  
Hiroyasu IWAHARA
Keyword(s):  
Hydrogen Isotope ◽  
Isotope Exchange ◽  
Isotope Effects ◽  
Oxide Ceramics ◽  
Hydrogen Isotope Exchange

FRACTIONATION OF GERMANIUM ISOTOPES IN CHEMICAL REACTIONS

1964 ◽  
Vol 42 (8) ◽  
pp. 1971-1978 ◽  
Author(s):  
H. M. Brown ◽  
H. R. Krouse
Keyword(s):  
Partition Function ◽  
Isotope Exchange ◽  
Isotope Fractionation ◽  
Kinetic Isotope Effect ◽  
Chemical Reduction ◽  
Isotope Effects ◽  
Equilibrium Constants ◽  
Kinetic Isotope Effects ◽  
Exchange Reactions ◽  
Kinetic Isotope

Isotopic vibrational frequencies and the corresponding partition-function ratios for several compounds containing Ge70 and Ge76 have been calculated at various temperatures. The theoretical equilibrium constants for germanium isotope-exchange reactions derived from these partition-function ratios indicate that noticeable germanium isotope fractionation might be effected with laboratory reactions. Calculated kinetic isotope effects in the breaking of diatomic bonds also predict observable alterations of the Ge70/Ge76 ratio.A kinetic isotope effect of 1.0% observed in the chemical reduction of GeO2 to GeO is discussed.

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.

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