Rhodium-catalyzed hydroformylation of unsaturated fatty esters in aqueous media assisted by activated carbon

Concerns about the environmental impact of chemical transformations prompted chemists to develop clean chemical processes using water as a solvent. Although appropriate for small partially water-soluble molecules, these processes do not allow for the transformation of hydrophobic substrates due to the mass transfer limitation between the aqueous and the organic phase. In this context, we show that activated carbons can be used as mass transfer additives to promote the rhodium-catalyzed hydroformylation of methyl oleate and other unsaturated olefins. Due to its mesoporous and hydrophobic character, the Nuchar (R) WV-B activated carbon proved to be especially effective as mass transfer promoter. Actually, a significant increase in the conversion was observed. Additionally, more than 90% aldehydes were formed during the course of the reaction. When compared to other mass transfer promoters such as co-solvents or cyclodextrins, Nuchar (R) WV-B was by far the most efficient. Thus, the use of activated carbons appeared to be a suitable solution for the aqueous rhodium-catalyzed hydroformylation of hydrophobic bio-sourced substrates.