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Article
Kinetic and Mechanistic Studies of the Deuterium Exchange in Classical Keto−Enol Tautomeric Equilibrium Reactions
Journal of Chemical Education (2010)
  • Michael A Nichols, John Carroll University
  • Mark J. Waner
Abstract

An extension of the classic keto−enol tautomerization of β-dicarbonyl compounds into a kinetic analysis of deuterium exchange is presented. It is shown that acetylacetone and ethyl acetoacetate undergo nearly complete deuterium exchange of the α-methylene carbon when dissolved in methanol-d4. The extent of deuteration may be monitored via NMR spectroscopy as a function of time. A mechanism for deuterium exchange is presented and shown to be consistent with a consecutive first-order process. The data for acetylacetone are consistent with steady-state kinetics, whereas those of ethyl acetoacetate illustrate nonsteady-state behavior, offering an accessible example where students might collect and analyze real data to examine the applicability of the steady-state approximation.

Disciplines
Publication Date
2010
Citation Information
Michael A Nichols and Mark J. Waner. "Kinetic and Mechanistic Studies of the Deuterium Exchange in Classical Keto−Enol Tautomeric Equilibrium Reactions" Journal of Chemical Education Vol. 87 Iss. 9 (2010)
Available at: http://0-works.bepress.com.library.simmons.edu/michael_nichols/1/