Hydrothermal Catalytic Upgrading of Model Compounds of Algae-Based Bio-Oil to Monocyclic Aromatic Hydrocarbons over Hierarchical HZSM-5

Stearic acid (SA) and hexadecanamide (HA), which are model compounds of algae-based bio-oil, were used to produce aromatics for catalysis by a hierarchical HZSM-5 zeolite under hydrothermal conditions. The results showed that the hierarchical HZSM-5 zeolite was more active than the traditional HZSM-5 parent zeolite. The molar yield of toluene, ethylbenzene, and xylene could reach (1.14 ± 0.05) × 100% (normal weight percentage yield = 40.77 wt %) when the reaction temperature was 400 °C. Moreover, the catalyst was stable and recyclable under hydrothermal conditions. Besides, the addition of acetic acid remarkably improved the deoxygenation (or denitrification) and aromatization efficiencies of the SA and HA mixture by more than 25%. This study provides a feasible approach to the valorization of algal biomass and the production of aromatics.