The aerobic oxidation of 5-(hydroxymethyl)furfural was investigated over solid ruthenium hydroxide catalysts in ionic liquids at elevated temperatures and pressures. Several different catalyst supports were tested in combination with various ionic liquids. The best result was obtained in [EMIm][OAc] at 100 °C with 30 bar of oxygen over Ru(OH) x /La2O3 which afforded 48 % of 2,5-furandicarboxylic acid and 12 % of 5-hydroxymethyl-2-furancarboxylic acid. During use the catalysts were found to leach some of the metal inventory. However, the leached Ru species did not contribute to the catalytic activity, thus verifying that the catalytic oxidation proceeded heterogeneously under the applied reaction conditions.
- Supported ruthenium hydroxide
- 5-(Hydroxymethyl) furfural
- 2,5-Furandicarboxylic acid
- Ionic liquids