The Kinetics of Isotope Effects in a Model Solvolysis System Involving One Optically Active Ion Pair Intermediate
The derivation of the observed first-order rate constants from the "exact" integrated rate equations for the kinetic scheme of reaction 1 is presented. It is shown that the solvolytic exponential first-order rate constant is a special case of the polarimetric rate constant and that the optical activity of the product is determined by a multiplicative ratio of rate constants for the optically important reactions of the ion pair intermediate. A form of the integrated first-order polarimetric rate equation with a linearly independent parameter set is presented. The functions for the first-order rate constants derived using the steady state approximation are special cases of the functions derived from the exact equations, as are the functions for the first-order rate constants for two systems which involve pre-equilibria followed by a slow product forming step. These functions cannot all be derived one from the other. A differential analysis of observed isotope effects as functions of isotope effects on the rate constants for reactions involving the intermediates is presented.