Patent ID: 7196234

Claim:
A scalable biocatalytic process for the preparation of S-1,1,1-trifluoro-2-propanol with an enantiomeric excess of >99% by asymmetric microbial reduction of 1,1,1-trifluoroacetone with Baker's yeast, comprising a) heating a suspension of Baker's yeast in 0.1–0.4 M phosphate buffer to a temperature of about 50–52° C. over a period of about 60 min, b) maintaining this suspension at a temperature of about 50–52° C. over a further period of about 90 min, c) diluting the heated suspension with buffer to a yeast concentration of about 20–30% w/v and cooling to a temperature of about 10° C. within a period of about 120 min, d) maintaining the pH constant at 7.4 to 7.5 by automatic addition of 4 M KOH solution over the whole process, e) adding 1,1,1-trifluoroacetone to a concentration of about 1–5% (w/v) at a temperature below the boiling point of 1,1,1-trifluoroacetone, f) reducing 1,1,1-trifluoroacetone to (S)-1,1,1-trifluoro-2-propanol at a temperature of about 20° C. within a period of about 5 to 8 days, and g) isolating the (S)-1,1,1-trifluoro-2-propanol by a sequence of distillation steps.