Octadecanol Production from Methyl Stearate by Catalytic Transfer Hydrogenation over Synergistic Co/HAP Catalysts

As a potential alternative for fossil feedstocks, renewable natural oils are highly desirable for producing fuels or high added-value chemicals. Herein, catalytic transfer hydrogenation of methyl stearate to octadecanol using methanol and water as hydrogen donors was investigated over Co/hydroxyapatite (HAP) catalysts synthesized by distinct methods. Multicharacterizations revealed that the strong interaction between Co and the HAP support of the Co/HAP catalysts could enhance the electron transferability, resulting in the excellent methyl stearate conversion (94.8%) and octadecanol selectivity (67.7%) at 290 °C in 5 h. The characterizations and density functional theory (DFT) calculations confirmed that the combined Co⁰/Co^δ+ active sites could synergistically boost the generation of H₂ and the hydrogenation of methyl stearate in the methanol/water system. In addition, the effects of various reaction conditions (e.g., the amount of methanol, reaction temperature, reaction time, and catalyst loading) were investigated in detail to understand the plausible reaction pathways. The results may have guiding significance on designing catalysts for efficient conversion of fatty acid methyl esters.