Understanding the Co/Mn/Br Synergistic Catalysis in Liquid Phase Oxidation of 5-Hydroxymethyl Furfural to 2,5-Furandicarboxylic Acid Based on the Effective Collision Theory

Abstract

2,5-Furandicarboxylic acid (FDCA) is an important monomer for the bio-based degradable polymer polyethylene 2,5-furandicarboxylate. Current kinetic studies on the preparation of FDCA by the liquid-phase oxidation of 5-hydroxymethyl furfural (HMF) have failed to quantitatively consider the effect of the ratio and concentration of Co/Mn/Br ternary catalysts, although they play an important role in the oxidation reaction rate and selectivity. In this work, an effective collision theory was introduced into the kinetic modeling, and then, a kinetic model of HMF oxidation with nine parameters was developed. The fitting results of this model using experimental data of HMF liquid phase oxidation with different catalysts and temperatures were satisfactory. The relative collision frequency coefficients α and β successfully describe the reactivity of Co and Mn, respectively, and they are only influenced by the water content in the solvent and do not vary with temperatures. The chain initiation rate constants are only temperature-dependent, and the other rate constants remain constant over the studied range. The kinetic model developed in this work would bring valuable insights into the synergistic effects of the Co/Mn/Br ternary catalyst components on the oxidation of HMF.