Preparation and characterization of alumina supported nickel-oxalate catalyst for the hydrodeoxygenation of oleic acid into normal and iso-octadecane biofuel

In this study, nickel II oxalate complex (NiOx) was prepared by functionalization of nickel with oxalic acid (OxA) and incorporated into Al2O3 to synthesize alumina supported nickel oxalate (NiOx/Al2O3) catalyst for the hydrodeoxygenation (HDO) of oleic acid (OA) into biofuel. The synthesized NiOx/Al2O3 was characterized and the X-ray fluorescence and elemental dispersive X-ray results showed that NiOx was successfully incorporated into the structure of Al2O3. The X-ray diffraction and Raman spectroscopy results confirmed that highly dispersed Ni species are present in the NiOx/Al2O3 due to the functionalization with OxA. The catalytic activity of the NiOx/Al2O3 on the HDO of OA produced a mixture of 21% iso-C18 and 72% n-C18 at a 360 °C, 20 bar, 30 mg NiOx/Al2O3 loading pressure and gas flow rate of 100 mL/min. The presence of i-C18 was ascribed to the OxA functionalization which increased the acidity of NiOx/Al2O3. The NiOx/Al2O3 reusability study showed consistent HDO ability after 5 runs. These results are promising for further research into biofuel production for commercialization.