期刊
BEILSTEIN JOURNAL OF ORGANIC CHEMISTRY
卷 10, 期 -, 页码 1787-1795出版社
BEILSTEIN-INSTITUT
DOI: 10.3762/bjoc.10.187
关键词
carbon dioxide; CO2 chemistry; cobalt complex; phthalic anhydride; propylene oxide; terpolymerization
资金
- Korea CCS R&D Center (KCRC) - Korea Ministry of Science, ICT and Future Planning [2012-0008935]
- Fundamental R&D Program for Integrated Technology of Industrial Materials - Korea Ministry of Knowledge Economy
The (salen)Co(III) complex 1 tethering four quaternary ammonium salts, which is a highly active catalyst in CO2/epoxide copolymerizations, shows high activity for propylene oxide/phthalic anhydride (PO/PA) copolymerizations and PO/CO2/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/CO2/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/CO2/PA terpolymerization, respectively). The terpolymers bearing a substantial number of PA units (f(PA), 0.23) showed a higher glass-transition temperature (48 degrees C) than the CO2/PO alternating copolymer (40 degrees C).
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