Beilstein J. Org. Chem.2018,14, 2779–2788, doi:10.3762/bjoc.14.255
complex (Table 2, entry 8). Finally, we attempted the terpolymerization of PO, HO, and PA (Scheme 2). Although equimolar amounts of PO and HO were used, the obtained copolymer contained a larger amount of the PO-derived repeating unit, reflecting a higher reactivity of PO.
Conclusion
We reported the
using (R,R,R,R)-1 at 30 °C for 15 min.
Synthesis of dinuclear cobalt–salen complexes (R,R,S,S)-2 and (R,R,R,R)-2.
Terpolymerization of PO, HO, and PA with (R,R,R,R)-1.
Copolymerization of propylene oxide (PO) with phthalic anhydride (PA) using cobalt–salen complexes.a
Copolymerization of various
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Graphical Abstract
Figure 1:
Structures of cobalt–salen complexes 1–4.
Beilstein J. Org. Chem.2014,10, 1787–1795, doi:10.3762/bjoc.10.187
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
, 1.05–1.5). Because of the extremely high activity of 1, high-molecular-weight polymers were generated (Mn 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 (fPA, 0.23) showed a higher glass
-transition temperature (48 °C) than the CO2/PO alternating copolymer (40 °C).
Keywords: carbon dioxide; CO2 chemistry; cobalt complex; phthalic anhydride; propylene oxide; terpolymerization; Introduction
Carbon dioxide (CO2) can be utilized to prepare aliphatic polycarbonates through coupling reactions
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Graphical Abstract
Scheme 1:
Synthesis of poly(propylene carbonate) (PPC) using catalyst 1.