Primary and secondary kinetic isotope effects in the acid-catalyzed dehydration of 1,1'-diadamantylmethylcarbinol in aqueous acetic acid

1981 ◽  
Vol 46 (2) ◽  
pp. 412-415 ◽  
Author(s):  
John S. Lomas
Keyword(s):  
Acetic Acid ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Aqueous Acetic Acid ◽  
Kinetic Isotope ◽  
Acid Catalyzed

Some Kinetic and Equilibrium Isotope Effects in the Isobutylphenone Eno land Enolate Ion System

1989 ◽  
Vol 44 (5) ◽  
pp. 406-412 ◽  
Author(s):  
Y. Chiang ◽  
A. J. Kresge ◽  
P. A. Walsh
Keyword(s):  
Acetic Acid ◽  
Isotope Effect ◽  
Acid Catalysis ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Free Energies ◽  
Kinetic Isotope ◽  
Hydronium Ion ◽  
Acid Catalyzed ◽  
Water Catalysis

The following kinetic isotope effects were determined for acid-catalyzed ketonization of isobutyrophenone enol and enolate ion through rate-determining hydron transfer from catalyst to substrate: enol, kH/kD = 3.30±0.07 (hydronium ion catalysis), kH/kD = 4.0 + 2.8 (acetic acid catalysis); enolate ion, kH/kD= 1.00 + 0.21 (hydronium ion catalysis), kH/kD = 3A \ +0.20 (acetic acid catalysis), kH/kD = 7.48±0.23 (water catalysis). The magnitude of these isotope effects, when assessed in terms of the free energies of reaction for the processes in which they occur, are consistent with Melander-Westheimer- Bigeleisen theory. An equilibrium isotope effect of KH/KD = 5.88±0.32 was also determined for the ionization of isobutyrophenone enol as an oxygen acid.

α-DEUTERIUM KINETIC ISOTOPE EFFECTS IN SOLVOLYSES OF endo-NORBORNYL p-BROMOBENZENESULFONATE

1965 ◽  
Vol 43 (8) ◽  
pp. 2254-2258 ◽  
Author(s):  
C. C. Lee ◽  
Edward W. C. Wong
Keyword(s):  
Acetic Acid ◽  
Formic Acid ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Aqueous Dioxane ◽  
Kinetic Isotope ◽  
Different Temperatures

endo-Norbornyl-2-d p-bromobenzenesulfonate was synthesized and the isotope effects, as measured by kH/kD, were determined over a range of temperatures for solvolyses in 30% water – 70% dioxane, acetic acid, and formic acid. Values of kH/kD are of the order of 1.20. The data appear to indicate slightly higher isotope effects as the solvents are changed from aqueous dioxane to acetic acid to formic acid, as well as somewhat higher isotope effects at lower temperatures. Possible mechanistic implications of these results are presented. Relative titrimetric acetolysis rates, kexo/kendo, at different temperatures, and enthalpies and entropies of activation for these acetolyses are evaluated and discussed.

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