Heterogeneous Catalytic Deoxygenation of Stearic Acid for Production of Biodiesel

TLDR

The study proposes a novel catalytic deoxygenation approach to convert fatty acids into diesel‑like hydrocarbons. Stearic acid was deoxygenated to heptadecane in a semibatch reactor at 300 °C and 6 bar, using a catalyst screening that identified the most effective metal–support combinations, which were characterized by N₂ physisorption, CO chemisorption, and H₂ temperature‑programmed desorption. A carbon‑supported palladium catalyst achieved >98 % selectivity, converting stearic acid completely into C₁₇ deoxygenated products.

Abstract

A novel method for production of diesel-like hydrocarbons via catalytic deoxygenation of fatty acid is discussed. The model compound stearic acid is deoxygenated to heptadecane, originating from the stearic acid alkyl chain. The deoxygenation reaction is carried out in a semibatch reactor under constant temperature and pressure, 300 °C and 6 bar, respectively. A thorough catalyst screening was performed to obtain the most promising metal and support combination. The catalysts were characterized by N2-physisorption, CO-chemisorption, and temperature-programmed desorption of hydrogen. A highly active and selective in the deoxygenation reaction of stearic acid carbon supported palladium catalyst converted stearic acid completely with >98% selectivity toward deoxygenated C17 products.