Chemo-enzymatic epoxidation of unsaturated carboxylic acids

Unsaturated carboxylic acids are converted to percarboxylic acids catalyzed by an immobilized lipase from Candida antarctica (Novozym 435 R). These unsaturated percarboxylic acids are only intermediates and epoxidize themselves in good yields and almost without consecutive reactions. The mechanism of the oxygen-transfer is found to be predominantly intermolecular and the formation of the percarboxylic acids proceeds via two different catalytic reactions. The lipase is surprisingly stable under the reaction conditions; it is recovered and reused fifteen times to produce epoxy-stearic acid on a multi-gram scale.