Esterification in Organic Media for Preparation of Optically Active Secondary Alcohols: Effects of Reaction Conditions

Abstract

Esterification in an organic solvent for enantioselective preparation of optically active secondary alcohols was investigated using porcine pancreas lipase (PPL), (R,S)-2-octanol and dodecanoic acid in heptane. The influence of different reaction conditions on esterification rate and enantioselectivity was studied. Removal of water and immobilization of PPL both led to distinct improvement of the extent of ester formation and enantioselectivity of catalysis. Studies allowing continuous control of optical enrichment in the product (ester) and the remaining substrate (alcohol) were carried out in order to further optimize the reaction conditions. Optically pure (R)-and (S)-2-octanol were prepared.

Key Words:

• Enantioselective lipase catalysis
• immobilization
• kinetic resolution
• optically pure alcohols
• organic media
• water content