The use of carbon dioxide in ruthenium carbonyl catalyzed 1-hexene hydroformylation promoted by alkali metal and alkaline earth salts Original Research Article

Carbon dioxide can be used as a CO source in the hydroformylation of alkenes. In the multi-step process, the CO2 is first reduced to CO and then used in situ in conventional hydroformylation. Under the condition of a CO2/H2 atmosphere the primary hydroformylation products, aldehydes, are hydrogenated as alcohols. The reaction can be catalyzed by ruthenium carbonyl compounds of various nuclearities such as H4Ru4(CO)12, Ru3(CO)12 and [Ru(CO)3Cl2]2 and promoted by the presence of halides and suitable counter ions such as alkali metal cations or alkaline earth cations. Both the halide and the cation are required for the positive promoting effect. The best results were obtained by using [Ru(CO)3Cl2]2/Li2CO3 system.