Rhodium Catalyst Immobilization in Trialkylamine-functionalized Ionic Liquids as a New Efficient Way to Promote Biphasic Reductive Hydroformylation of Methyl 10-undecenoate

Abstract

In this work, trialkylamine-functionalized ionic liquids were assessed for their dual role as solvents and ligands in the biphasic reductive hydroformylation of methyl 10-undecenoate (MU), a renewable substrate derived from castor oil. Systematic tuning of the aminated ionic liquids through cation and anion variation identified 1-(2-piperid-1-yl-ethyl)-3ethanolimidazolium hexafluorophosphate, [PEEtOHim][PF6] combined with dodecane as the most effective biphasic couple, enabling efficient rhodium reductive hydroformylation with a turnover frequency in alcohols of 33 h -1 while limiting rhodium leaching in the apolar phase to as little as 1.5% of its initial loading. Under optimized conditions, /the system was recycled for at least nine consecutive runs with constant selectivity in alcohols, highlighting the robustness of the catalytically active species stabilized within the ionic liquid phase. A cumulative total turnover number in alcohols of 1282 was achieved through this atom-economical tandem process, further demonstrating the potential of aminated ionic liquids in biphasic catalytic systems. This work underscores the relevance of ionic liquid-based strategies for sustainable catalysis and the valorization of renewable feedstocks, bridging high-performance chemistry with the principles of green chemistry.