In:
Beilstein Journal of Organic Chemistry, Beilstein Institut, Vol. 10 ( 2014-08-05), p. 1787-1795
Abstract:
The (salen)Co(III) complex 1 tethering four quaternary ammonium salts, which is a highly active catalyst in CO 2 /epoxide copolymerizations, shows high activity for propylene oxide/phthalic anhydride (PO/PA) copolymerizations and PO/CO 2 /PA terpolymerizations. In the PO/PA copolymerizations, full conversion of PA was achieved within 5 h, and strictly alternating copolymers of poly(1,2-propylene phthalate)s were afforded without any formation of ether linkages. In the PO/CO 2 /PA terpolymerizations, full conversion of PA was also achieved within 4 h. The resulting polymers were gradient poly(1,2-propylene carbonate- co -phthalate)s because of the drift in the PA concentration during the terpolymerization. Both polymerizations showed immortal polymerization character; therefore, the molecular weights were determined by the activity (g/mol- 1 ) and the number of chain-growing sites per 1 [anions in 1 (5) + water (present as impurity) + ethanol (deliberately fed)], and the molecular weight distributions were narrow ( M w / M n , 1.05–1.5). Because of the extremely high activity of 1 , high-molecular-weight polymers were generated ( M n up to 170,000 and 350,000 for the PO/PA copolymerization and PO/CO 2 /PA terpolymerization, respectively). The terpolymers bearing a substantial number of PA units ( f PA , 0.23) showed a higher glass-transition temperature (48 °C) than the CO 2 /PO alternating copolymer (40 °C).
Type of Medium:
Online Resource
ISSN:
1860-5397
Language:
English
Publisher:
Beilstein Institut
Publication Date:
2014
detail.hit.zdb_id:
2192461-2
Permalink