Promising Recyclable Ionic Liquid-Soluble Catalytic System for Reductive Hydroformylation

We report here the reductive hydroformylation of methyl 10-undecenoate (issued from castor oil) in a biphasic liquid/liquid system. The rhodium/amine catalytic system is immobilized in an ionic liquid phase, whereas the olefin and the products are in a nonpolar layer. The effects of various reaction parameters (nature and concentration of amines, nature of ionic liquids, temperature and syngas pressure or composition) were studied to increase the production of primary alcohols. Under optimized conditions, potassium N,N-dimethyltaurinate salt associated with rhodium, immobilized in 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, allowed us to attain 93% of alcohol yield. With only 2 equiv of amine with respect to rhodium, the catalytic system can be efficiently immobilized in the ionic liquid and recycled due to the ionic nature of the involved catalytic species