Linear long-chain α-olefins from hydrodeoxygenation of methyl palmitate over copper phyllosilicate catalysts

Copper phyllosilicate (CuPS) was used as a bifunctional catalyst for hydrodeoxygenation of methyl palmitate (MP) to produce long-chain α-olefins without the loss of carbon backbone. The CuPS catalysts were prepared by ammonia evaporation-hydrothermal method. The crystal structure, surface area, reducibility, Cu dispersion, Cu particle size and acidity of the catalysts were examined by XRD, BET, H₂-TPR, TEM, NH₃-TPD and Py-IR. The existence of Cu²⁺ species (octahedral (O_h)/square planar (Sq)), Cu⁺ and Cu⁰ upon calcination/reduction was investigated by in situ TR-XANES. The Cu dispersion was related to the Cu⁺ fraction in CuPS, while Brønsted acid sites (BAS) depends on Cu⁰ particles. The MP conversion to 1-hexadecene proceeds via hydrogenation-dehydration promoted by the synergy of Cu⁰ surface and Brønsted acid sites at the interface. The α-olefin selectivity depends on a balance between Cu⁺ and Cu loading. The 20CuPS possessing 10% Cu⁺ fraction, provides a high conversion of 72% with 45% α-olefin selectivity.