NaBH4 In-situ Reduced Cobalt Catalyst Supported on Zeolite A for 1-Hexene Hydroformylation

Zeolite A with different pore sizes (3 A, 4 A and 5 A) were selected as supports for preparing a series of cobalt catalysts through wetness impregnation method, using NaBH4 as an in-situ reducing agent, but without further reduction. X-ray photoelectron spectra (XPS) confirmed the reduction of cobalt. Transmission electron microscopy (TEM) images revealed that the cobalt nanoparticles were formed evenly on the zeolite structure by our rapid synthesis method. The catalytic activity of the prepared catalysts was investigated for the hydroformylation of 1-hexene. Benefiting from the spatial confinement effect derived from the unique topology structure of zeolite A and the low temperature in-situ reduction contributed by NaBH4, the conversion of 1-hexene to C-7 aldehyde with a significantly enhanced normal heptanal selectivity (normal/iso ratio of 1.93) was achieved. The present study provides a rapid and effective way for the synthesis of zeolite supported cobalt catalysts for the hydroformylation of 1-hexene.