In situ FTIR study of low-pressure hydroformylation of 1-hexene catalyzed by ultrafine cobalt nanoparticles

Abstract The hydroformylation of 1-hexene in syngas (CO:H 2 = 1) under 2–3 MPa at 100 °C was catalyzed using 2.8 nm ultrafine cobalt nanoparticles and investigated by in situ Fourier transform infrared spectroscopy (FTIR). A group of bands observed in the in situ FTIR spectra at 2071, 2041, and 2022 cm −1 are assigned to terminal CO adsorptions distributed over different Co sites. A band at 2054 cm −1 is attributed to the intermediate, RCH 2 CH 2 COCo, which has been observed for the first time. Through this intermediate, the catalytic reaction proceeds via the elimination of RCH 2 CH 2 COCo to leave a single H atom on the surface of each 2.8-nm Co nanoparticle.