Reactions of 2,2'-Methylenebis(4-chloro-6-isopropyl-3-methylphenol) and 2,2'-Ethylidenebis(4,6-di-tert-butylphenol) with Mg~nBu_2:Efficient Catalysts for Ring-Opening Polymerization of epsilon-Caprolactone and L-Lactide

摘要

Three novel magnesium aryloxides,[(MCIMP)_2Mg_2(THF)]_2 (1),[(EDBP)Mg(Et_2O)]_2 (2),and [(EDBP)Mg(THF)]_2 (3),have been synthesized by the reaction of 2,2'-methylenebis(4-chloro-6-isopropyl-3-methylphenol) (MCIMP-H_2) or 2,2'-ethylidenebis(4,6-di-tert-butylphenol) (EDBP-H_2) with Mg~nBu_2 in diethyl ether or tetrahydrofuran,respectively.Experimental results show that 1-3 efficiently catalyze the ring-opening polymerization of epsilon-caprolactone and L-lactide in a controlled fashion,yielding polymers with very narrow polydispersity indexes in a wide range of monomer-to-initiator ratios.Compound 1 has paved a way to synthesize as much as 500-fold polymer chains of poly(epsilon-caprolactone) with a very narrow polydispersity index.In addition,block copolymers such as poly(epsilon-caprolactone)-b-poly(L-lactide),poly-(ethylene glycol) methyl ether-b-poly(L-lactide),and polystyrene-b-poly(L-lactide) have also been prepared.