Enhanced selective production of aldehydes and ketones by catalytic upgrading of pyrolysis vapor from holocellulose over red mud-based composite catalysts

This work proposes an effective method for the utilization of agricultural residues and red mud (RM) to produce the carbonyl platform compounds for the synthesis of high-value biofuels. The carbonyl platform compounds were synthesized by catalytic upgrading of pyrolysis vapor from holocellulose over RM composite catalyst. The maximized yield of aldehydes and ketones was obtained with the cellulose-to-hemicellulose mass ratio of 3:2, which was consistent with that of bagasse. Two types of RM were selected for the carbonylation of pyrolysis vapors, in which the type prepared by Bayer process containing more Fe2O3 exhibited better carbonylation performance. The ZrO2-loaded RM composite catalyst was prepared, and it was found that the yield of aldehydes and ketones was greatly boosted. Finally, RM composite catalysts supported by five individual metal oxide were prepared, the correlation between the oxidizability of catalyst and the aldehyde/ketone mole ratio was established, and it was revealed that the stronger oxidizability of the composite catalysts was usually accompanied with the decreased aldehydes/ketones mole ratio. Biomass and RM wastes were used as resources in this study, this waste-to-energy idea contributes to optimizing the utilization of waste and promoting the production of biofuels.