Experiments and Kinetic Modeling on the Co/Mn/Br Catalyzed Oxidation of Prehnitene to Mellophanic Acid in the Liquid Phase

Mellophanic acid (MPA) was prepared by liquidphase oxidation of prehnitene (PR) using Co/Mn/Br as the catalyst and acetic acid/water as the solvent in this work. The effects of temperatures and catalyst concentration and ratio on the yield of MPA and trimellitic acid (TMA) were investigated. It was found that improving reaction temperatures can significantly enhance the yield of MPA, and the higher ratio of Mn and concentration of Br in the catalyst is beneficial to increase the yield of both MPA and TMA. Based on the complex radical chain mechanism of hydrocarbon oxidation, the reaction pathway of PR oxidation was proposed and a lumped kinetic model including the most important intermediates and final products was established. The number of kinetic model parameters was much reduced through the Hammett structure-reactivity relationship. The model reliability was confirmed by comparisons with experimental data. Hopefully, the results obtained in this work can bring insights into the liquid-phase oxidation of other polyalkyl aromatic hydrocarbons.