Direct esterification of citronellol and lauric acid catalyzed by immobilized lipase B from Candida antarctica was performed in supercritical carbon dioxide with different organic solvents and ionic liquids serving as co-solvents. The highest concentration of citronellol laurate after 1 h of reaction performance (3.95 mmol/g substrates) was obtained in SC CO2 with ethyl methylketone serving as a co-solvent. The optimal temperature and pressure for citronellol laurate synthesis in SC CO2/EMK medium was determined to be 60 degrees C and 10MPa. (C) 2007 Elsevier B.V. All rights reserved.