Catalytic upgrading of bio‐oil: Hydrodeoxygenation study of acetone as molecule model of ketones

The complexity of composition of bio‐oil from biomass makes it difficult to produce upgraded bio‐oil via hydrodeoxygenation. In this paper, acetone is thus considered as a model compound of the ketones family abundant in pyrolysis bio‐oil. Results showed that high conversion rates of acetone between 86.6% and 91.9% were observed with the use of HZSM‐5, 5% Ni2P/HZSM‐5, and 10% Ni2P/HZSM‐5 catalysts. In most cases, CO2, C2H6, C3H6, and C3H8 were the dominant non‐condensable gas products. For liquid phase, the selectivity was evaluated for different catalysts relative to ethanol, acetaldehyde, and aromatic hydrocarbons. A lower temperature favoured the formation of acetaldehyde and methyl isobutyl ketone with the 5% Ni2P/HZSM‐5 catalyst, while higher temperatures increased the proportion of aromatic hydrocarbons. The principal influencing parameters of acetone HDO were temperature and contact time followed by reaction pressure and H2 partial pressure. Optimal conditions give a selectivity of 49% of aromatics (benzene, toluene, and xylene) with the use of the 5% Ni2P/HZSM‐5 catalyst. The pathway of the main reactions of acetone HDO was also proposed. MIK and aromatic hydrocarbons were formed by a multiple step aldol condensation reaction of acetone molecules followed by further hydrogenation.