Microkinetic modeling of cis-cyclooctene oxidation on heterogeneous Mn–tmtacn complexes

Abstract

Experiments and microkinetic modeling were used to investigate the reaction mechanism of cis-cyclooctene oxidation with H2O2 on heterogeneous manganese 1,4,7-trimethyl-1,4,7-triazacyclononane (Mn–tmtacn) catalysts. A mechanism based on literature reports and model discrimination was identified that captured experimental data well, including data at reaction conditions that were not used for parameter estimation. H2O2 activation on the heterogeneous catalytic complex was identified as the rate-determining step (RDS), and a simple analytical rate expression was derived using the RDS and the pseudo-steady-state approximation for all intermediates. Predicted reaction orders for cis-cyclooctene, water, H2O2, catalyst, and diol and epoxide products are also consistent with experimental observations and can be rationalized according to the derived rate expression. In addition, the ratio of productive to unproductive H2O2 use is analyzed, and catalyst deactivation is found to be an important step in the reaction mechanism that is highly sensitive to temperature.