Abstract:

Considering the challenges of traditional homogeneous olefin hydroformylation processes，such as difficult product separation，metal leaching，and the insufficient catalytic activity and selectivity of conventional supported heterogeneous catalysts，a series of nitrogen/phosphorus-doped carbon material in-situ modified Co-based mesoporous silica catalysts（Co/L@SiO₂） were synthesized.The synthesis process involved using Co as the active metal to coordinate with organic nitrogen/phosphorus compounds for preparing catalyst precursors，which were then loaded onto mesoporous silica，followed by high-temperature calcination and reduction.The composition，structure，and morphology of the catalysts were characterized using inductively coupled plasma optical emission spectrometry（ICP-OES），X-ray photoelectron spectroscopy（XPS），transmission electron microscopy（TEM），N₂ physical adsorption，and Raman spectroscopy.The results demonstrated that the Co/Py@SiO₂ catalyst，synthesized with pyridine as the precursor ligand，exhibited a specific surface area of 618.76 m²/g，with uniform mesopores averaging approximately 3.6 nm in size.The catalyst contained 0.92%~0.94% metallic Co，with an average Co particle size of 6.4 nm and almost no agglomeration.Compared with Co@SiO₂，the nitrogen-doped Co/Py@SiO₂ catalyst showed a significant improvement in the selectivity toward n-valeraldehyde in the hydroformylation of mixed C4 hydrocarbons，increasing from 57.3% to 85.2%.The Co/Py@SiO₂ catalyst maintained stable activity and selectivity in fixed-bed continuous evaluation experiments.This study provided a practical approach to improve the reactivity and selectivity of heterogeneous hydroformylation catalysts，showing potential for industrial application.

Key words: n-valeraldehyde, nitrogen-doped carbon materials, silica, ligand, heterogeneous catalyst