Pyrolysis and liquefaction biocrudes obtained from lignocellulose are rich in phenolic compounds that can be converted to renewable aromatics. In this study, Pt catalysts on reducible metal oxide supports (Nb2O5, TiO2), along with irreducible ZrO2 as a reference, were investigated in the liquid‐phase hydrodeoxygenation (HDO) of 4‐propylphenol (350 °C, 20 bar H2, organic solvent). The most active catalyst was Pt/Nb2O5, which led to the molar propylbenzene selectivity of 77 %, and a yield of 75 % (98 % conversion). Reducible metal oxide supports provided an increased activity and selectivity to the aromatic product compared to ZrO2, and the obtained results are among the best reported in liquid‐phase. The reusability of the spent catalysts was also studied. The spent Pt/Nb2O5 catalyst provided the lowest conversion, while the product distribution of the spent Pt/ZrO2 catalyst changed towards oxygenates. The results highlight the potential of pyrolysis or liquefaction biocrudes as a source of aromatic chemicals.

managed responsibly. [2,3] Such renewable biofuels are especially promising for sustainable aviation. [4] The biopolymers that constitute lignocellulose can be broken down, among other means, by liquefaction. [5-7] Liquefaction relies on thermochemistry (200-400 °C) and on a liquid solvent, such as a high boiling point hydrocarbon. [6,7] The same solvent can be used in subsequent upgrading steps. The product of liquefaction is biocrude: a complex mixture of phenolics, furanics, cyclic ketones, carboxylic acids, and other compounds. [6] The high concentration of oxygenates renders biocrudes chemically unstable, poor in heating value, corrosive, highly viscous, and prone to form coke. [6,8] Hence, further upgrading is necessary, with a possible upgrading step being hydrodeoxygenation (HDO): a type of hydrotreatment, in which biocrude constituents react with dihydrogen on a heterogeneous catalyst, producing deoxygenated compounds and water. [8] Fittingly, HDO can proceed in the presence of an organic solvent. [7] Liquefaction biocrudes are highly unsaturated (60-65% carbon) and resemble lignin or pyrolysis liquids. [6] They are rich in phenolic compounds, and hence they are a potential source of bio-based aromatic hydrocarbons. Aromatic hydrocarbons are essential to the chemical industry, [9-12] and they are also required in fuels. [4] For example, international standards stipulate that jet fuel should contain 8% to 25% aromatics. [4,13,14] Although the abundant phenolics produced in liquefaction are suitable for conversion to aromatic hydrocarbons via HDO, the challenge, especially with alkylphenols, is that the aryl-hydroxyl bond is among the strongest in lignocellulose. [8] Furthermore, it is necessary to prevent the hydrogenation of the aromatic ring. Thus, in order to overcome these obstacles, it is pertinent to study the HDO of alkylphenols, for which catalyst development is essential. Many factors in the HDO process can influence the performance of a HDO catalyst. Some of these factors are the reaction medium, [15,16] the reaction temperature and pressure with their thermodynamic and kinetic effects, [17] and the ortho, meta, and para isomerism of alkylphenols. [18] Sulfided catalysts are considered conventional in commercial hydrotreatment. [19,20] Unfortunately, the activity of sulfided The alkylphenols found in liquefied lignocellulose could become a source of biobased aromatic hydrocarbons for fuel components. In the hydrodeoxygenation (HDO) of alkylphenols, hydroxyl groups must be removed while avoiding the hydrogenation of the aromatic ring. Here, the HDO of propylphenols is studied using a Pt/Nb 2 O 5 catalyst and n-tetradecane solvent. HDO experiments are performed using different reaction conditions of batch residence time (0-161 min g cat g reactant −1), pressure (20-30 bar H 2), and temperature (300-375 °C). HDO is studied with ortho-, meta-, and para-propylphenol. The influence of vapor-liquid equilibrium and chemical equilibrium are assessed using thermodynamic calculations. Almost full deoxygena...