Investigation of the hydroformylation of ethylene in liquid carbon dioxide

In situ, high-pressure NMR was used to investigate the hydroformylation reaction of ethylene in liquid CO2 using Rh(CO)2acac as the catalyst precursor and (p-CF3C6H4)3P, tris(p-trifluoromethylphenyl)phosphine, as the ligand under different thermodynamic conditions (T=10–23 °C, PCO=PH2=10–15 bar, PC2H4=10–15 bar, PCO2=207 bar). 1H-NMR was used to monitor the reaction progress of the hydroformylation of ethylene with a rhodium catalyst under select conditions of temperature and CO2 solvent pressure. Potential resting states of the rhodium catalyst were investigated by 31P{1H}-NMR. This is the first description of a rhodium catalyzed hydroformylation reaction in liquid CO2 monitored in situ by high pressure NMR.