Upscaled Catalytic Production of Renewable Biofuels from Hexanoic Acid

Abstract

The hydrodeoxygenation (HDO) reaction plays a crucial role in the catalytic upgrading of bio-derived platform chemicals to renewable fuels and chemicals. Given its industrial versatility, the production of primary alcohols via the catalytic hydrodeoxygenation of carboxylic acids has been explored using the RuSn/ZnO catalyst demonstrating high performance and robust stability in high-pressure continuous-flow reaction systems. However, the complex synthesis procedures of this catalyst impose limitations on its applicability and scalability. Additionally, powder catalysts could cause a pressure drop across the catalytic beds, causing another challenge in a large-scale operation. To address these issues, a simplified preparation method for RuSn/ZnO catalyst utilizing commercial support was developed and pelletized sing methylcellulose and bentonite as binder. The pellet catalysts, with varying binder ratios (wt_binder/wt_cat), were evaluated for the hydrodeoxygenation of hexanoic acid under different reaction conditions. Characterization results confirmed the formation of Ru₃Sn₇ alloy on the RuSn/ZnO-5 (wt_binder/wt_cat⁼0.05) catalyst, which selectively produced 1-hexanol with a yield of 72.7% under optimized reaction conditions. Notably, the RuSn/ZnO-30 catalyst could selectively produce biofuel components (1-hexanol and hexyl hexanoate) with high stability in 0.403 L/day of hexanoic acid hydrodeoxygenation. The developed catalytic system offers the potential for advancing biomass conversion as a viable alternative to the conventional petrochemical processes, contributing to the industrialization of sustainable fuels and chemicals production.