The experimental study on the air oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid with Co–Mn–Br system

Abstract

Abstract 2,5-Furandicarboxylic acid (FDCA), an eco-friendly biomass resource capable of replacing petroleum-based fuels, is gaining increasing popularity. In this article, 2,5-FDCA was prepared by liquid-phase oxidation of the sustainable precursor 5-hydroxymethylfurfural using the Co–Mn–Br catalyst system. The effects of catalyst concentration, catalyst ratio, reaction temperature, reaction time, reaction pressure, and solvent ratio on the reaction of FDCA were investigated. The products are subjected to qualitative and quantitative analyses using high-performance liquid chromatography, infrared spectroscopy, and hydrogen nuclear magnetic spectroscopy. Moreover, considering the loss of catalytic liquid, the suitable reaction conditions were determined as follows: n(Co)/n(Mn)/n(Br) = 1/0.04/0.5, n(HMF)/n(HAC) = 0.05, reaction temperature of 170°C, reaction pressure of 2 MPa, reaction time 40 min, and airflow rate 1.0 L·min−1. Under these conditions, the yield of the product is 86.01%, the purity is 97.53%, and the loss of the catalytic liquid is about 5.63%, which is at an ideal level and provides a good basis for the recovery of the subsequent catalytic liquid and multiple cycle reactions. Through the optimization of the existing process, the use of noble metal catalysts has been reduced, and the recycling of catalytic liquid has also reduced the consumption of catalysts. This advancement marks a significant stride toward sustainable development in the green chemical industry.