Understanding the formation and stability of cobalt-based catalysts for homogeneous carbonylation reactions

Cobalt carbonyls are crucial for the 100% atom-economical hydroformylation of alkenes. While traditional industrial processes require harsh conditions (100–400 bar, 100°C–250°C), our work explores catalyst performance under significantly milder, energy-efficient parameters. Using in situ Fourier transform infrared (FTIR) spectroscopy complemented by density functional theory (DFT) calculations, we present a comprehensive investigation into the stability and interconversion of the active species, HCo(CO) 4 , and its precursors, Co 2 (CO) 8 and Co 4 (CO) 12 . We establish that HCo(CO) 4 is stable at pressures as low as 10 bar and 120°C. For the first time, we directly monitored the catalyst's formation from various sources, including Co 4 (CO) 12 , Co(acac) 2 , and Co(OAc) 2 . The activation mechanism of a cationic bisphosphine Co(II) precursor is also elucidated. This research provides a critical foundation for analyzing and optimizing cobalt-based catalysts, paving the way for more sustainable industrial processes.