Preparation Of Potassium Ferrate And Its Application In The Preparation Of 2,5-furandicarboxylic Acid From 5-Hydroxymethylfurfural

Wood biomass was mainly composed of cellulose, hemicellulose and lignin. And cellulose is a macromolecular polymer, which is made up of glucose units linked with(1â†'4) glycosidic bond. It can be converted to 5-hydroxymethylfurfural(HMF), a biomass-based platform compound by catalytic dehydration, and subsequently converted to 2,5-furandicarboxylic acid(FDCA) by catalytic oxidantion. FDCA possesses the same structure with petroleum based polyester monomer, terephthalic acid(PTA), which can be used as the substitute of PTA for the biomass-based polymer production. In this paper, we propose the preparation of potassium ferrate and then applied it in the oxidation of HMF to FDCA, therefore, the optimum technological parameters can be obtained, and a theoretical basis can be provided for the green and efficient production of the key biomassbased polyester monomer, FDCA.In this paper, potassium ferrate was firstly prepared through a modified hypochlotite oxidation method. And then, the puried potassium ferrate was obtained by adding purification step in the preparation process of potassium ferrate. Simultaneously, the composited oxidant which contains Fe and Mn was prepared by doping an amount of potassium permanganate in the preparation process of potassium ferrate. The purity of the potassium ferrate and the puried one were 15.26 % and 26.13 % respectively, which was analyzed by chromite titration.The optimum reaction conditions for the oxidation of HMF toFDCA were obtained through the discussion of alkali charge, the amount of oxidant, reaction time and reaction temperature. It was found that the optimum reaction conditions when potassium ferrate was used as the oxidant were as follows, 1.6 mol/L of alkali charge, 2.0 mol/L of oxidant amount, 15 min and 25 °C, the maximum yield of FDCA was 87.2 %. When the puried potassium ferrate was regarded as the oxidant, the optimum reaction conditions were 1.4 mol/L of alkali charge, 1.3 mol/L of oxidant amount, 15 min and 35 °C, the maximum yield of FDCA was 86.6 %. And when the composited oxidant was used as the oxidant, the optimum reaction conditions were as follows, 1.6 mol/L of alkali charge, 1.8 mol/L of oxidant amount, 15 min and 25 °C, the maximum yield of FDCA was 91.0 %.It is proved that the reduciont product of potassium ferrate was Fe2O3 after the XPS and FTIR characterization, which was an environment-friendly material. It was also observed that the reduction product of the composited oxidant was Fe2O3 and a small amount of MnO2. Furthermore, the experimental results revealed that a small amount of Fe2O3 would improve the oxidation ability of potassium ferrate. Moreover, the preparation process of FDCA derived from HMF by the oxidation of potassium ferrate was monitored by HPLC, and only one intermediate product was observed. Thus, a possible reaction mechanism was proposed.The proposed method in this paper has some obvious advantages, which has low request for the preparation apparatus. Furthermore, the preparation method is simple and inexpensive, which has mild reaction conditons, short reaction time and no secondary pollution. This method has an important guiding significance to the industrialized production of FDCA.