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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 22, Number 8
BKCSDE 22(8)
August 20, 2001 

 
Title
Solvolyses of N-Methyl-N-phenylcarbamoyl Chlorides with Electron Acceptor Substituents in Aqueous Binary Mixtures
Author
In Sun Koo, Sun Kyoung An, Kiyull Yang, Han Joong Koh, Moon Ho Choi, Ikchoon Lee
Keywords
Solvolyses, Ring parameter transition state, Isotope effect, Dissociative SN2 mechanism.
Abstract
Solvolyses of N-methyl-N-phenylcarbamoyl chlorides in aqueous binary mixtures of acetone, ethanol, methanol and in water, D2O, and 50% D2O-CH3OD are investigated at 25.0 ℃. The Grunwald-Winstein plots of first-order rate constants for N-methyl-N-phenylcarbamoyl chlorides with YCl (based on 2-adamantyl chloride) show a dispersion phenomenon. The ring parameter (I) has been shown to give considerable improvement when it is added as an hI term to the original Grunwald-Winstein and extended Grunwald-Winstein correlations for the solvolyses of N-methyl-N-phenylcarbamoyl chlorides. This study has shown that the magnitude of l, m and h values associated with a change of solvent composition is able to predict the dissociative SN2 transition state. The kinetic solvent isotope effects determined in deuterated water are consistent with the proposed mechanism of the general base catalyzed and/or a dissociative SN2 mechanism channel for N-methyl-N-phenylcarbamoyl chlorides solvolyses.
Page
842 - 846
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