The purpose of this research was to study the effect of the methyl
branching of a high log P alkane solvent and the water activity in the
organic medium on the initial rate and the enantioselectivity of
ibuprofen esterification catalyzed by Candida rugosa lipase.
Resolution of ibuprofen is important because S-(+)-ibuprofen has the
desired pharmacological activity, whereas the R-(-)-enantiomer causes
much of the side effects. The Candida rugosa lipase-catalyzed reaction
in isooctane at 40°C and 0.73 water activity gave the best
results, both in terms of the initial reaction rate and the
enantioselectivity of the reaction. An increase in water activity
allowed a higher reaction rate and enantiomeric excess in each of the
four solvents. An increase in methyl branching did not necessarily
increase the initial reaction rate, but it allowed a higher
enantioselectivity, evidenced by an increase in the substrate
enantiomeric excess