This work describes the lipase-mediated synthesis of oleoyl ethanolamide, a dietary supplement for body weight loss recently approved by FDA. The target compound is prepared by conversion of the oleic acid contained in a mixture of fatty acids recovered by enzymatic hydrolysis of soapstock, a side-product of high oleic sunflower oil refinement. The use of a packed-bed reactor (a glass column loaded with the commercial lipase Lipozyme 435) in continuous flow mode improves the space-time yield of the reaction and the catalyst productivity. The nontoxic, bioderived, and renewable solvent limonene is used in the reaction medium. The process has been run for more than 157 h of continuous operation, demonstrating the stability and efficiency of the biocatalyst. Additionally, at the end of the reaction, only oleoyl ethanolamide crystallizes from the reaction mixture, thus, it is collected by simple filtration of the outlet solution in 53% isolation yield, showing 99% chemical purity, while all the byproducts of the reaction are left behind in the mother liquors
