One-pot terpolymerization of CO2, cyclohexene oxide and maleic anhydride using a highly active heterogeneous double metal cyanide complex catalyst

• Published in: Polymer (Guilford) Vol. 51; no. 24; pp. 5719 - 5725
• Main Authors: Sun, Xue-Ke, Zhang, Xing-Hong, Chen, Shang, Du, Bin-Yang, Wang, Qi, Fan, Zhi-Qiang, Qi, Guo-Rong
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 12.11.2010; Elsevier
• Subjects: Applied sciences; Carbon dioxide; Catalysts; Copolymerization; Cyclohexene; Double metal cyanide complex; Ethers; Exact sciences and technology; Maleic anhydride; Organic polymers; Oxides; Physicochemistry of polymers; Preparation, kinetics, thermodynamics, mechanism and catalysts; Terpolymerization; Terpolymers; Zinc; Double metal cyanide complex; Terpolymerization; Carbon dioxide; Chemoselectivity; Zinc complex; Complex catalyst; Thermal stability; Heteronuclear complex; Unsaturated copolymer; Reaction mechanism; Carbonate copolymer; Maleate copolymer; Cobalt III Complexes; Solution copolymerization; Experimental study; Cyano complex; Complex catalyst copolymerization; Maleic anhydride; Heterogeneous catalysis; Ester copolymer; Pressure copolymerization; Preparation; Epoxide; Catalyst activity; Ring opening copolymerization
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2010.09.044

This paper describes a convenient one-pot terpolymerization of CO2, cyclohexene oxide (CHO) and maleic anhydride (MAH) to afford a poly (ester-carbonate) with a low content of ether units (2.9–4.3 mol%) using a highly active Zn–Co(III) double metal cyanide complex (DMCC) catalyst. Terpolymerization was carried out in tetrahydrofuran (THF) at 75–90 °C and 1.0–4.0 MPa and no cyclic carbonate was observed in NMR spectra. The number-average molecular weight (Mn) of the terpolymer was up to 14.1 kg/mol with a narrow molecular weight distribution of 1.4–1.7. The apparent efficiency of the catalyst was up to 12.7 kg polymer/g Zn, representing the highest catalytic activity for terpolymerization of CO2, epoxides and cyclic anhydrides to date. THF dramatically inhibited polyether formation in this terpolymerization owing to its nucleophilicity towards the Zn2+ center of Zn–Co (III) DMCC. This presents the first example of solvent-assisted selectivity for inhibiting ether units in CO2 polymerization catalyzed by a heterogeneous system. Kinetic analyses of MAH/CHO/CO2 terpolymerization (MAH/CHO 0.2) suggested that polyester production was slightly faster than polycarbonate production in the early stage. A mechanism for this terpolymerization catalyzed by Zn–Co (III) DMCC catalyst was proposed. Moreover, addition of small amounts of MAH (MAH/CHO molar ratio ≤0.2) during CO2/CHO copolymerization can improve the thermal properties of the resultant terpolymers. [Display omitted]