Catalytic Conversion of Fructose and 5‑Hydroxymethylfurfural into 2,5-Furandicarboxylic Acid over a Recyclable Fe<sub>3</sub>O<sub>4</sub>–CoO<sub><i>x</i></sub> Magnetite Nanocatalyst

2015-03-02T00:00:00Z (GMT) by Shuguo Wang Zehui Zhang Bing Liu
A nano-Fe<sub>3</sub>O<sub>4</sub>–CoO<sub><i>x</i></sub> catalyst was prepared via a simple wet impregnation method. The nano-Fe<sub>3</sub>O<sub>4</sub>–CoO<sub><i>x</i></sub> catalyst showed good catalytic performance for the conversion of 5-hydroxymethylfurfural into 2,5-furandicarboxylic acid (FDCA) with <i>t</i>-BuOOH as the oxidant. Several important reaction parameters were explored, with the highest FDCA yield of 68.6% obtained from HMF after 15 h at a reaction temperature of 80 °C. One-pot conversion of fructose into FDCA was also successful via two steps. Catalytic conversion of fructose over Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub>–SO<sub>3</sub>H yielded 93.1% HMF, which was oxidized in situ into FDCA with a yield of 59.8%. Furthermore, recycling of nano-Fe<sub>3</sub>O<sub>4</sub>–CoO<sub><i>x</i></sub> was accomplished with the help of a magnetic field. Nano-Fe<sub>3</sub>O<sub>4</sub>–CoO<sub><i>x</i></sub> showed high stability in the reaction process. The use of nonprecious metals and no requirement of a base additive made this method much more economical and environmentally friendly.