Selective synthesis of 2, 5-furandicarboxylic acid by oxidation of 5-hydroxymethylfurfural over MnFe2O4 catalyst

Development of green catalytic processes using biobased feedstock for valuable chemicals such as 5-hydroxymethylfurfural (HMF) is hotly pursued. 2, 5-Furandicarboxylic acid (FDCA), a bio-based alternative to terephthalic acid was efficiently synthesized by oxidation of HMF using MnFe2O4 spinel structured magnetic nanoparticles (MNPs) and tert-butyl hydroperoxide as an oxidant. MnFe2O4 catalyst showed the highest activity and selectivity and gave 85% yield of FDCA at 100 degrees C in 5 h. The higher activity of MnFe2O4 catalyst is due to the variable oxidation state of manganese. The combination of MnFe2O4 catalyst and TBHP oxidant requires less time and energy compared to other reported processes of FDCA synthesis. Also, many reported methods have used a homogeneous base for FDCA synthesis which is totally avoided in the current process. The concentration profiles of reactants and products were established and kinetics determined. The effects of various reaction parameters were studied to validate kinetic model. The catalyst was easily recycled due to its magnetic property and showed good catalytic activity up to four cycles. All metal ferrites were characterized by different analytical techniques. The catalyst maintained its fidelity.