Solvolyses of N-Methyl-N-phenylcarbamoyl Chlorides with Electron Acceptor Substituents in Aqueous Binary Mixtures

[摘要] 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 Y_Cl (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 S_N2 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 S_N2 mechanism channel for N-methyl-N-phenylcarbamoyl chlorides solvolyses.

[学科分类] 化学（综合）

[关键词] Solvolyses;Ring parameter transition state;Isotope effect;Dissociative SN2 mechanism.