Process for the preparation of polymers of dimeric cyclic esters

摘要

The present invention provides a process for the direct synthesis of high melting polymers made from dimeric cyclic esters. In particular, the present invention provides a process for synthesis of polylactic acid (PLA) from racemic materials such as racemic lactide and polymandelide from mandelide. The process further provides racemic metal organic ligand catalysts such as racemic salbinap that catalyzes the polymerization of racemic dimeric cyclic ester monomers to a polylactide stereocomplex. Polymandelide and mixed dimeric cyclic esters are also prepared in the presence of low amounts of water.