Theoretical performance of countercurrent reactors for production of enantiopure compounds

Irreversible reactions are being applied in enzymatic kinetic resolution to obtain enantiomerically pure compounds from racemic mixtures. Using model calculations for situations without mass transfer limitation, we show that reversible reactions might also be useful for enzymatic kinetic resolution, provided that countercurrent systems are used rather than batch or cocurrent systems. The required reaction time or enzyme amount in a countercurrent system is much lower than in an analogous cocurrent system or its batch equivalent. More importantly, often the calculated yield and enantiomeric excess are better in countercurrent systems. Racemization can also be favorably used in countercurrent systems. Consequently, to achieve with a reversible reaction a particular enantiomeric excess and yield, a countercurrent system needs less dilution or activated co-reactant and less enantioselective enzyme than a cocurrent system.