The high-entropy oxide-promoted oxidative condensation reaction of biomass-derived furfural with aliphatic alcohol in the presence of O 2

The high entropy oxides are widely studied as the potential catalytic materials owing to their unique structure and excellent properties. In this work, a new high entropy oxide catalyst MnFeCoNiCuO x was successfully prepared and used for the oxidative condensation reaction of furfural (FUR) and aliphatic alcohol, where the carbon-chain length can be selectively increased under the mild conditions. For the selective oxidative transformation of FUR with n-butanol, a more than 99.0 % conversion of FUR and 91.5 % selectivity of 2-(furanyl-2-methylene) butanal was obtained at 80 ºC for 2 h. In addition, the oxidative condensation of FUR with ethanol, n-propanol, n-pentanol, n-hexanol and n-heptanol was also carried out with the MnFeCoNiCuO x - LiOH as catalyst system in the presence of molecular oxygen, where a moderate to high product yields were acquired. Furthermore, the characterizations of catalyst showed that the existence of abundant oxygen vacancy and high specific area was greatly important to the catalytic reactions.