Catalytic deoxygenation of oleic acid in continuous gas flow for the production of diesel-like hydrocarbons

Continuous gas phase deoxygenation of oleic acid in the presence of hydrogen employing a granular 2 wt% Pd/C catalyst was investigated under solvent free conditions. Conversion of oleic acid and selectivity to the desired diesel-like C17 hydrocarbons heptadecane and heptadecenes was studied at different reaction conditions such as temperature, gas flow and catalyst amount. The best hydrocarbon yield was achieved with low reaction temperatures, high catalyst amounts and high hydrogen flows. To further decrease the reaction temperature but yet maintain a pure gas phase reaction, reactions were conducted in vacuum. Furthermore, water was added in varying amounts to support desorption and to determine if catalyst deactivation could be overcome. The deoxygenation catalyst was characterized by nitrogen adsorption isotherms (BET; Brunauer–Emmet–Teller method), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA) and field emission scanning electron microscopy (FESEM).

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► Diesel-like hydrocarbons from renewable feedstock.
► Decarboxylation and decarbonylation reactions took place.
► Continuous gas phase reactions under solvent-free conditions.
► Up to 28.5% selectivity to C17 hydrocarbons.