Germany – Another development in the field of hydroformylation has been produced by a research team that includes Evonik and the LIKAT (Leibniz Institute for Catalysis).
One of the most significant processes in commercial organic chemistry is hydroformylation. Synthesis gas is used to transform unsaturated chemicals into aldehydes and alcohols.
The general assumption among scientists up until recently was that this reaction if cobalt were to be the catalyst, could only take place at high pressures without the catalyst disintegrating. Professor Dr. Robert Franke, director of hydroformylation research at Evonik, and colleagues Drs. Baoxin Zhang and Christoph Kubis from LIKAT debunked this.
Cobalt carbonyls, which are relatively cheap chemicals for the catalysis of hydroformylation, were successfully shown for the first time to be active and stable even at low-pressure. The creation of unique spectroscopic measuring techniques and related mathematical tools for data analysis was essential to this finding.
Future lower-pressure methods may take the place of high-pressure ones that utilize cobalt carbonyls as catalysts. The resulting new procedures would be more economical, energy-efficient, and hence more sustainable. This would have an effect on Evonik’s ability to produce long-chain alcohols like the oxo alcohol isononanol (INA), which is utilized, among other things, in the creation of plasticizers.
The findings of the experiment were published in the esteemed publication Science as a consequence of the discovery’s specific significance. Professor Dr. Robert Franke has spoken twice about carbonylation processes in Science. A so-called “dream reaction,” the direct carbonylation of 1,3-butadiene, was accomplished by Franke in 2020. This discovery was likewise deserving of journal publishing.
Surfactants and plasticizers are produced industrially using hydroformylation using a cobalt carbonyl catalyst that has not been changed. However, syngas pressures of 100 to 400 bar are routinely used, with reaction temperatures of 100 to 250°C. Here, we demonstrate that at 140 °C and 30 bar of syngas, unaltered cobalt carbonyl is a stable hydroformylation catalyst. The performance was equivalent to that of previously published bisphosphine-coordinated cobalt(II) catalysts, which we were unable to duplicate under the same circumstances. The stability of the unaltered cobalt tetracarbonyl hydride [HCo(CO)4] was validated by kinetic and in situ infrared spectroscopy measurements. Low syngas pressures and the absence of phosphorus ligands allowed for the highly regioselective conversion of branched internal olefins to aldehydes. At phosphorus-to-cobalt loading ratios under 0.6, bisphosphines exhibited a negligible catalytic impact.