Investigation of CoNi/Hydroxyapatite for Catalytic Deoxygenation of Biorenewable Platform Molecules under Solvent-Free Conditions

The catalytic roles of biominerals and naturally abundant supporting materials like HAP are key factors in the geological formations of fossil fuels from biomass. Herein, we are inspired to synthesize Co- and Ni-supported HAP catalysts that can transform methyl oleate into diesel-grade hydrocarbons. In our investigation, the Ni-HAP catalyst shows more favorable behavior toward decarboxylation/decarbonylation and the Co-HAP catalyst promotes excellent selectivity in hydrodeoxygenation (HDO), while the combined effect of CoNi-HAP followed both the decarboxylation/decarbonylation and hydrodeoxygenation routes. The catalytic hydrogenation of methyl oleate using a Co-HAP catalyst revealed a 100% conversion with C18 selectivity of 85.5% at 280 °C, 8 h, and 15 bar pressure. Meanwhile, Ni-HAP shows 100% conversion with C17 selectivity of 89.6% at 280 °C, 12 h, and 15 bar pressure. The CoNi-HAP shows a 100% conversion with the mixed C17 and C18 hydrocarbons. The Co-HAP, Ni-HAP, and CoNi-HAP catalysts are used under solvent-free conditions, which are industrially feasible and offer significant economic and environmental benefits for large-scale production. During six test cycles, the catalyst can be recycled and reused. These insights may open the door to developing a catalyst with high catalytic performance.