Catalytic decarbonylation of stearic acid to hydrocarbons over activated carbon-supported nickel

Abstract

In this study, the deoxygenation of stearic acid over a series of Ni-based catalysts in the absence of hydrogen and solvents was investigated. Ni/Al₂O₃, Ni/TiO₂, Ni/ZrO₂, and Ni/AC (activated carbon) were synthesized using the wetness impregnation method, and Ni/AC showed the best activity for deoxygenation. X-ray diffraction, transmission electron microscopy, H₂ temperature-programmed reduction, and N₂ adsorption–desorption analyses revealed that Ni had an average particle size of about 9.6 nm with good crystallinity, the largest surface area and strong Ni–carrier interactions in Ni/AC. These properties of Ni/AC contributed to its good deoxygenation activity. Ni/AC produced hydrocarbons (71.4% yield) such as heptadecane, heptadecene, aromatics, and cracking paraffins under optimized reaction conditions. Furthermore, it was found that the deoxygenation of stearic acid over Ni/AC in the absence of hydrogen and solvent proceeds mainly via decarbonylation.