Kinetics of the Recovery of Active Anthraquinones

Epoxided alkyltetrahydroanthraquinone (epoxide) is formed as a byproduct in the oxidation of hydrogenated alkyltetrahydroanthraquinone in hydrogen peroxide production. Because epoxide is unable to form hydrogen peroxide it has to be converted back to active quinones. The epoxide conversion was carried out over a sodium-promoted aluminum oxide. Besides the main reaction, the oxidized form of anthraquinone also underwent a disproportion reaction. The conversion kinetics was registered in an isothermal slurry reactor operating batchwise at 60-80 °C. A kinetic model based on plausible surface reaction steps was derived, and the parameters included in the model were estimated by nonlinear regression analysis. The model explained the experimental data with satisfactory accuracy and can be used to predict the epoxide conversion kinetics over commercial catalysts.