RARE EARTH METAL COORDINATION COMPOUNDS AS LACTONE POLYMERIZATION CATALYSTS

摘要

the invention relates to a process for polymerization of lactide and up to 20 mol% of a lactone. the catalysts used in the formula, m represents the mz3, scandium, yttrium, bismuth, a rare earth metal of the lanthanide series, or a mixture thereof, and z is independently of the same different ligand coordination.preferred metals m are lanthanum, cerium, neodymium, lanthanum, prasu00e9odymium and particularly preferred). the preferred ligands are bu00eatadicu00e9tones, bu00eatacu00e9toesters and bu00eatadicu00e9tones malonate anions, such as tetramethyl - 3.5 - heptanedionates 2,2,6,6-tetramethylpiperidine is particularly preferred.