Recovery of solubilized rhodium from hydroformylated vegetable oils and their methyl esters

Procedures were developed to extract rhodium from hydroformylated vegetables oils and methyl esters. Among the numerous reagents surveyed, aqueous hydrogen cyanide with triethanolamine (TEA) was found to be most effective. The effects of time, temperature, and concentration of reagents were studied. Over 98% of the solubilized rhodium was removed from crude methyl formylstearate at 100 C for 1 hr with 0.5% hydrogen cyanide, 5% water, and 0.5% TEA. Over 98% of the solubilized rhodium was also extracted from hydroformylated soybean and safflower methyl esters; however, 1% hydrogen cyanide, 10% water, and 0.62% TEA had to be used. Only 90% of the rhodium was removed from hydroformylated soybean oil. The reagents used can be adpated to a continuous extraction procedure.