Enzymatic synthesis of oleyl oleate in dense fluids

Esterification between oleic acid and oleyl alcohol, catalyzed by theMucor miehei immobilized lipase in a batch-stirred tank reactor with supercritical carbon dioxide as solvent produced higher reaction rates at supercritical conditions than in the solvent-free system. A continuous fixed-bed reactor was designed based on the results obtained from batch experiments. At 150 bar, 40°C, and with water activity 0.46% w/w, the activity of the enzyme preparation is practically unchanged when CO₂ was used as solvent. The addition of small amounts of water increases the conversion rate. The higher conversion also was observed at longer residence time. Whenn-butane was used as reaction medium, a decrease in conversion was observed.