Lipase-catalysed kinetic resolution of racemates at temperatures from 40 degrees C to 160 degrees C in supercritical CO2

The reaction rate and selectivity of the enzymatic kinetic resolution of ib uprofen and 1-phenylethanol with supercritical CO2 as solvent were studied in a batch reactor from 40 degrees C to 160 degrees C. The commercial enzym e, Novozym 435, remained partly active for at least 14 h up to 140 degrees C at 15 MPa. The maximum reaction rate for the esterification of 1-phenylet hanol and ibuprofen was at about 90 degrees C. The enantiomeric excess for 1-phenylethanol exceeds 99% and was temperature independent. Selectivity fo r ibuprofen esterification reached a lower enantiomeric excess of 61% cause d by equilibrium adjustment. The results show that with supercritical CO2 a s reaction medium enzymes remain active above 100 degrees C.