• Title/Summary/Keyword: 2,2,2-Trichloro-1,1-dimethylethyl chloroformate

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Kinetic Studies of the Solvolyses of 2,2,2-Trichloro-1,1-Dimethylethyl Chloroformate

  • Koh, Han-Joong;Kang, Suk-Jin;Kevill, Dennis N.
    • Bulletin of the Korean Chemical Society
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    • v.31 no.4
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    • pp.835-839
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    • 2010
  • The rate constants of solvolyses of 2,2,2-trichloro-1,1-dimethylethyl chloroformate ($\underline{I}$) in 33 solvents can be well correlated using the extended Grunwald-Winstein equation, with incorporation of the $N_T$ solvent nucleophilicity scale and the $Y_{Cl}$ solvent ionizing scale, with sensitivities towards changes in the scale having values of $1.42\;{\pm}\;0.09$ for l and $0.39\;{\pm}\;0.05$ for m, respectively. The activation enthalpies are ${\Delta}H^{\neq}\;=\;12.3$ to $14.5\;kcal{\cdot}mol^{-1}$ and the activation entropies are -28.2 to $-35.5\;cal{\cdot}mol^{-1}{\cdot}K^{-1}$, consistent with the proposed bimolecular reaction mechanism. The kinetic solvent isotope effect of 2.14 in MeOH/MeOD is in accord with a bimolecular mechanism, probably assisted by general-base catalysis.