Process for preparing (R) and (S)-1,2-isopropylideneglycerol by crystallizing racemic benzoyl ester

A process for separating the optical isomers from a racemic mixture of 1,2-isopropylideneglycerol benzoyl ester of the formula (II):

• comprising the steps of:
• (a) hydrolyzing partially, enantioselectively and enzymatically 1,2-isopropylideneglycerol benzoyl ester of the formula (II), wherein said hydrolysis is catalyzed by a free or immobilized lipase in an aqueous buffered solution, with a cosolvent selected from the group consisting of linear aliphatic ethers, branched aliphatic ethers and heterocyclic ethers;
• (b) separating the (S) enantiomerically enriched benzoyl ester (II) fraction from the (S) enantiomerically enriched alcohol;
• and
• (c) crystallizing (R,S) benzoyl ester (II) in racemic form from the (S) enantiomerically enriched benzoyl ester fraction derived in step (b) from C.sub.5 -C.sub.8 aliphatic hydrocarbons which leaves, predominately, the selectively obtained (S) enantiomer of the benzoyl ester (II) in the mother liquor.