| Abstract: | A combination of numerical integration of the rate equations and experimental measurement of the time‐dependence of rates rather than concentrations is described for the analysis of the catalytic cycle by which Noyori's catalyst, trans‐RuCl2[(S)‐binap][(S,S)‐dpen], hydrogenates acetophenone. The method is simpler in practice than usual kinetic methods and yields furthermore rate constants for activation, dihydrogen cleavage, and hydride transfer to substrate under realistic catalytic conditions. The specific results for the asymmetric hydrogenation of acetophenone show that the turnover‐limiting step changes from dihydrogen cleavage to hydride transfer if the H2 pressure is increased, but also during the course of the reaction when the hydrogenation is performed under typical conditions. |
