UEBER DIE Si-N-BINDUNG. XLII. BESTIMMUNG DER AKTIVIERUNGSPARAMETER FUER DIE HYDROLYSE VON TRIMETHYLSILYLURETHANEN DES TYPS Me3Si(p-XC6H4)NCOOEt

Article abstract of DOI:10.1016/S0022-328X(00)99137-X

Hydrolysis reactions of silylurethanes Me3Si(p-XC6H4)NCOOEt with X = Cl, H or Me in aqueous buffer solutions, with pH values of 2.33, 3.80, and 9.38 and at temperatures of 20, 30, and 40 deg C were studied.The catalytic rate constants for the acid- and base-catalysed reactions and for the "non-catalysed" reaction k(H3O⁺), k(OH^-), and k₀ were evaluated from the pseudo first-order rate constants k_exp, determined by UV spectroscopy.Activation parameters were obtained by means of the Arrhenius or Eyring equation from the dependence of rate constants of the temperature.From ρ values and activation parameters we assume for the acid and general base-catalysed reactions a S_N2-Si mechanism with more or less clear d-participation at the silicon atom and for the OH^--catalysed reaction a S_N2-Si mechanism.