Continuous Flow Hydrodeoxygenation of Lignin‐Derived Guaiacol to Cyclohexanol over Durable Al2O3 Hollow Fiber Supported Co Catalyst

Abstract The drive to decarbonize the chemical, oil, and gas industries through use of bio‐derived resources is intensifying. This study focuses on converting lignin‐derived phenolic compounds into cyclohexanol, a precursor for adipic acid production. The alumina hollow fiber supported cobalt catalyst (5Co/AHF@capillary) prepared by capillary action method was found to consist cobalt in both metallic and +δ oxidation states. Initial tests in a batch‐mode reactor showed promising results, with 5Co/AHF@capillary catalyst demonstrating catalytic activity comparable to Ru/Al₂O₃ systems (225 °C, 1 MPa H 2 , 4 h), achieving ∼86% cyclohexanol yield in guaiacol hydrodeoxygenation reactions. The catalytic system was then adapted for continuous flow reactors under milder conditions (300 °C, 2.5 MPa H 2 , 18 mL min −1 ), resulting in 83% guaiacol conversion and 74% cyclohexanol yield. The durability of the catalyst was checked for >80 h and results claim that catalyst was active in yielding consistent results. The roles of catalyst preparation method, hydrogen pressure, solvent, WHSV were thoroughly checked and discussed.