Scheme 3. Proposed Reaction Network of the One-Step Process for Demethoxylation and Dealkylation over (a) Stacked-Bed and (b) Mixed-Bed of Au/TiO₂ and HZSM-5 Catalysts in Benzene Using a Fixed-Bed Reactor (Conditions: 5 mol % 4-Propylguaiacol in Benzene, 350 °C, 100 bar, Gas Flow Rate 30 mL/min H₂, WHSV 30 h^–1).