Catalytic Upgrading of Oleic Acid to Aromatic Hydrocarbons by Tandem Deoxygenation and Aromatization over MoO₃/HZSM-5

The global petrochemical sector confronts escalating regulatory and environmental pressures for the production of platform chemicals such as benzene, toluene, ethylbenzene, and xylenes (BTEX), thereby necessitating a transition from petroleum-derived feedstocks to sustainable, biobased feedstocks. Unlike traditional hydrocarbon feedstocks, these biobased alternatives predominantly comprise of oxygenated compounds, which undergo multistep chemical transformations to produce BTEX. Such processes typically require hydrotreating conditions and rely on expensive noble metal catalysts, posing significant economic and operational concerns. Herein, we demonstrate a novel one-pot catalytic approach for direct conversion of oleic acid (OA) into aromatics under subcritical hydrothermal conditions. Oleic acid was strategically selected as the model compound due to its abundance in nonedible oils and thermodynamic stability under our operating temperatures. Using a MoO3/HZSM-5 catalyst without additional H2 requirement, tandem deoxygenation–aromatization of OA resulted in a total hydrocarbon yield of ca. 77% (net) or 90% theoretical yield versus decarboxylated intermediates. The liquid products obtained were characterized by infrared (IR) and 1H NMR spectroscopy as well as GC-FID analysis. Multivariate design of experiments with parametric evaluation of temperature (350 °C–375 °C), reaction time (1–4 h), and catalyst loading (0–10%) resulted in 65% BTEX selectivity and complete deoxygenation of OA. This efficiency surpasses conventional approaches and leverages an efficient catalyst for tandem deoxygenation-aromatization chemistry, thereby providing a scalable route to decarbonize aromatic production while valorizing lipid waste streams─a critical advancement towards circular chemical manufacturing.