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Polylactones, 43 . Polymerization of L ‐lactide catalyzed by zinc amino acid salts
Author(s) -
Kricheldorf Hans R.,
Damrau DirkOlaf
Publication year - 1998
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/(sici)1521-3935(19980801)199:8<1747::aid-macp1747>3.0.co;2-2
Subject(s) - racemization , chemistry , catalysis , polymerization , zinc , polymer chemistry , amino acid , reactivity (psychology) , glycine , lactide , pyroglutamic acid , proline , organic chemistry , polymer , biochemistry , medicine , alternative medicine , pathology
The usefulness of the zinc salts of five different amino acids or amino acid derivatives as polymerization catalyst of L ‐lactide was studied and compared. The five amino acid (derivatives) were: N ‐acetyl‐glycine, N ‐tosylglycine, L ‐proline, L ‐pyroglutamic acid and N ‐acetyl‐4‐aminobenzoic acid. All polymerizations were conducted in bulk. Due to the low reactivity of all Zn catalysts a reaction temperature of 150°C was needed to obtain yields around 90%. While the basic Zn prolinate caused partial racemization, the neutral Zn salts yielded poly( L ‐lactides) with 97–100% optical purity. Regardless of catalyst and reaction conditions only moderate molecular weights were obtained.