Process for the production of optically-active esters of lactic acid and lactyllactic acid

摘要

A process for treating a mixture of R,R- and S,S-lactide is provided. The process involves contacting the lactide mixture with an aliphatic alcohol and/or an alkoxide to produce a mixture of R,R- and S,S-aliphatic ester of lactyllactic acid, subsequently contacting the mixture of R,R- and S,S-aliphatic ester of lactyllactic acid with an enzyme to produce a mixture comprising aliphatic ester of lactic acid corresponding to one lactide enantiomer and the aliphatic ester of lactyllactic acid corresponding to the other lactide enantiomer, and recovering the product. Also provided are processes for the production of S-lactic acid, S,S-lactide, poly-S-lactic acid, R-lactic acid, R,R-lactide, poly-R-lactic acid and stereocomplex polylactic acid.

主权项

1. A process for producing an aliphatic ester of lactic acid and an aliphatic ester of lactyllactic acid, one of said esters being in the R form and the other being in the S form, characterised by the steps of:
(a) contacting a mixture of R,R- and S,S-lactide with an aliphatic alcohol and/or an alkoxide to produce a mixture of R,R- and S,S-aliphatic ester of lactyllactic acid; (b) subsequently contacting the mixture of R,R- and S,S-aliphatic ester of lactyllactic acid with aliphatic alcohol and an enzyme to produce a mixture comprising aliphatic ester of lactic acid corresponding to one lactide enantiomer (R or S), and the aliphatic ester of lactyllactic acid corresponding to the other lactide enantiomer (S or R); and (c) recovering aliphatic ester of lactic acid and/or aliphatic ester of lactyllactic acid from the mixture produced in step (b).